# The &showfoto; Handbook

Gilles
Caulier

    caulier_dot_gilles_at_free.fr

Gerhard
Kulzer

    gerhard at kulzer.net

2004
2005
The &showfoto; developers team
&FDLNotice;
2005-11-14
0.3.0

digiKam logo

&showfoto; is a KDE stand alone Photo Editor based on digiKam Image Editor. &showfoto; is a part of digiKam project.

KDE
digikam
showfoto
Graphics

## Introduction

### Background

#### About &showfoto;

&showfoto; is a fast Image Editor with a few basic yet powerful image editing tools. You can use it to view your photographs and make corrections and alterations.

#### Reporting Bugs

Like the rest of KDE, &showfoto; is an Open Source project. This means that it relies on its users to play their part by, at least, reporting problems and suggesting possible improvements.

&showfoto; makes it as easy as possible for you to report bugs or suggest improvements. Wherever you are in the application the Help menu will include a Report Bugs option. This will display a message box with a highlighted link. Click on the link and your web browser will open the page for the reporting system. All the information required will already be filled in, just follow the instructions for completing your report.

#### Support

&showfoto; is a community supported project, which means that users and developers support one another. If you become a regular user of &showfoto; you are encouraged to join the &showfoto; Users Mailing List. You can start off by asking questions of other &showfoto; users and hopefully soon you will be answering the support questions of others.

&showfoto; Users Mailing List joining instructions.

You can also visit the digiKam Home Page. for news of new releases and other &showfoto; related information.

#### Getting Involved

There are many ways that you can get involved with the continued development of &showfoto;. You do not need to be a software developer. You can help with documentation, translation and user interface design or just contribute really good ideas to the wish-list. You can also get involved by testing early development code as it is being developed and providing feedback to the developers. Of course, if you are a software developer then you can help to make &showfoto; the best digital photograph application there is.

The best way to start getting involved with &showfoto; is to join the Developers Mailing List. &showfoto; Developer Mailing List joining instructions.

### Supported Image File Formats

#### Still Photograph Formats

##### Introduction

Almost all digital cameras store photographs in one of two formats: JPEG or TIFF. Many cameras enable you to select which of these formats to use. A full description of these formats can be found at the Wikipedia. &showfoto; supports both of these formats.

##### Still Image Compression

Image compression is the application of data compression on digital images. In effect, the objective is to reduce redundancy of the image data in order to be able to store or transmit data in an efficient form.

Image compression can be lossy or lossless. Lossless compression methods is always be preferred for high value content for archival purposes before to apply transformations like croping, resizing, color corrections, etc. This is because lossy compression methods, especially when used at low bit rates, can introduce compression artifacts. Lossy methods are especially suitable for natural images such as photos in applications where minor (sometimes imperceptible) loss of fidelity is acceptable to achieve a substantial reduction in bit rate. Lossy compression is dedicaced to publish photographs on internet.

##### JPEG

JPEG is a compressed format, that trades some of the image quality to keep file sizes small. In fact, most cameras save their images in this format unless you specify otherwise. A JPEG image is stored using lossy compression and you can vary the amount of compression. This allows you to choose between lower compression and higher image quality or greater compression and poorer quality. The only reason to choose higher compression is because it creates smaller file so you can store more images, and it's easier to send them by e-mail, or post them on the Web. Most cameras give you two or three choices equivalent to good, better, best although the names vary.

##### TIFF

TIFF has been widely accepted and widely supported as an image format. Commonly, TIFF may be stored by the camera in uncompressed form or using lossless compression algorithm (Adobe Deflate). It maintains higher image quality but at the expense of much larger file sizes. Some cameras let you save your images in this format and it is a popular format because of its lossless compression algorithm. The problem is that the format has been altered by so many people that there are now 50 or more flavors and not all are recognizable by programs.

##### PNG

PNG is an image format that was developed as a replacement for a number of older, in the 1990's widely used, image file formats. It is a lossless format like TIFF but it is much more compact and saves disk space. Although your camera is unlikely to support PNG, some people like to convert their photographs to PNG as soon as they get them on their computer. Unlike JPEG, PNG images do not loose quality every time you re-encode them after modification. &showfoto; fully supports PNG images.

PNG is an extensible file format for the lossless, portable, well-compressed storage of raster images. PNG provides a patent-free replacement for GIF and can also replace many common uses of TIFF. PNG is designed to work well in online viewing applications, such as the World Wide Web, so it is fully streamable with a progressive display option. Also, PNG can store gamma and chromaticity data for improved color matching on heterogeneous platforms. PNG supports 8 and 16 bits / colors /pixels depth. It's the perfect file format to archive your photographs. For more information about the PNG format see the PNG homepage.

##### RAW

Some, typically more expensive, cameras allow you to store images in RAW format. RAW format is not really an image standard at all. It is different for every make of camera. RAW format images contain all the data that is taken directly from the camera's image sensor before the software in the camera applies things like white balance, sharpening etc. Storing photographs in a camera's RAW format allows you to alter settings, such as white balance, after the photograph has been taken. Most professional photographers use RAW format, because it offers them maximum flexibility. The downside is that RAW image files can be very large indeed. If you want to learn more about RAW image format visit the very helpful guides The Luminous Landscape and Cambridge in Colour.

&showfoto; do not yet support to load RAW image files. You can convert RAW format images into JPEG or TIFF with digiKam using the RAW Image Converter plugin.

#### How &showfoto; Supports File Formats

&showfoto; relies on a number of libraries and support packages to load and save image formats. Which image formats are available will depend on the availability of these libraries on your system and, in some cases, on the way that those libraries have been compiled. On most distributions you will find that a wide range of image formats are viewable within &showfoto;.

This dependence on other libraries means that it is not possible to give a definitive list of all of the formats that will be available on your system. At the very least JPEG, PNG, and TIFF will be available.

### Supported Plugins

One of the nicest things about &showfoto; is how easily its functionality can be extended, by using digiKam Image Editor Plugins: these plugins add new image manipulation options. &showfoto; support the image plugin core included in digiKam (if installed) to perform basic image manipulations like Red Eyes Correction, Aspect ration crop, etc. Others plugins from DigikamImagePlugins project are also supported. This one is dedicated to providing a collection of advanced image editor tools. Image Editor Plugins setup is described in this section.

Plugins supported by &showfoto;

Plugins can manipulate images in almost any way that users can. Their advantage is, that it is much easier to add a capability to &showfoto; by writing a small plugin than by modifying the &showfoto; core.

## Using &showfoto;

### &showfoto; Image Editor

#### Introduction to Image Editor

&showfoto; provides a number of tools that enable you to adjust a photograph. Some of these tools are provided by plugins to &showfoto;. So they may not be available by default on your distribution. See the Setup Plugins Section for more details about &showfoto; plugins.

##### The Main Window

&showfoto; has just one main window with:

- A status at the bottom which shows the filename, the current file number, the current zoom level, and the current image size.

- A Menu Bar across the top and below that a Tool Bar that provides quick access to some commonly used functions.

- A thumbs bar on the right shows the preview of currents image files loaded. Just right click with mouse to change the current image in editor.

The Main Toolbar

- (1) : First Image in current list.

- (2) : Previous Image.

- (3) : Next Image.

- (4) : Last Image in current list.

- (5) : Save the modified image.

- (6) : Undoing last action.

- (7) : Redoing previous action.

- (8) : Restore the Current Image From Disk.

- (9) : Zoom Into the Image.

- (10) : Zoom Out of the Image.

- (11) : Toggle Auto Zooming (if selected image will fit in the window).

- (12) : Rotate the Current Image.

- (13) : Crop Image to the Selected Region.

- (14) : Toogle to full screen.

- (15) : Run slide show tool.

#### Restoring Your Original Photograph

The editing functions of the Image Editor will make changes to your photograph. None of the editing functions will change the original photograph unless you select File Save or click the Save button in the Tool Bar. Note that once you have saved the changed version you will not be able to recover the original photograph.

You might prefer to take a copy of your photograph before you make any changes. You can use File Save As to save a working copy.

At any time before you save your photograph you can restore the view to the original image by selecting File Revert or clicking the The Image Editor Revert Button Revert button on the Tool Bar. You will loose any changes that you have made to the photograph since it was last saved.

#### Undoing/Redoing Actions

Almost anything you do to an image in Image Editor can be undone/redone. You can undo the most recent action by choosing Edit Undo, and redo by Edit Redo

If these are done so frequently that you really should memorize the keyboard shortcuts, Ctrl-Z to undoing action, and Ctrl-Shift-Z to redoing action.

To get a popup menu with the available undo/redo actions, you have to press the left mouse button at the undo or redo icon in the toolbar and hold it down for a moment. If you choose one of the menu items, all undo/redo actions until the choosen one are done.

#### Moving Between Photographs

Once you have started the Image Editor with several images at once you can move between photographs by using the navigator buttons on the Tool Bar or the entries in the File menu. If you show the thumbnail bar you can also navigate by clicking the thumbnails. When you have made any changes to the current photograph you will be asked if you want to save them.

#### Changing the View

You can zoom in and out of a photograph using the The Image Editor Zoom Buttons buttons on the Tool Bar or the entries in the View menu. To make a photograph fit into the window use the Zoom Autofit The Image Editor AutoFit Button button on the Tool Bar.

View Toggle Full Screen will display the photograph using the full screen mode. You can move back to the normal view by pressing the Esc key. By default the Tool Bar is still displayed even in Full Screen Mode. If you would prefer that the Tool Bar is not displayed you can turn it off in the Configure &showfoto; dialog accessed from the main &showfoto; window, see the Setup General Section.

#### Image Properties

##### EXIF Viewer Tool

###### What is EXIF?

EXIF stands for EXtended Interchange Format. It was designed specifically for digital cameras. It allows a large amount of information about the photograph to be stored. Those informations are describing the camera which took the image along with the settings (including date and time) in use when the picture was taken. Also it allows an inline thumbnail to be included.

EXIF format contains different marker sections named Image File Directories (IFD). The sections likely to be found in a normal EXIF file are as follows:

- 0: contains general information about the photograph.

- 1: contains information about the embedded thumbnail image.

- EXIF: contains extended information about the photograph.

- GPS: contains Global Positioning System information provides by the camera during the capture.

- Interoperability: contains information to support interoperability between different EXIF implementations.

- Thumbnail: displays the embedded thumbnail image.

###### How to Use EXIF Viewer?

You can review embedded EXIF information for the image using Image Properties and EXIF page. The EXIF Viewer is purely informational: nothing you do with it will cause any change to the EXIF sections.

###### The EXIF Viewer in Action

You can use two different levels to display EXIF marker sections:

- Simple: display only EXIF marker.

- Full: display all markers excepted thumbnails.

Some vendors add additional EXIF sections, such as Canon, Fujifilm, Nikon, and Sigma. These sections contain vendor and model specific notes. These will be displayed with Full level.

For the EXIF data displayed, EXIF Viewer provides a contextual help. Select an item on the top and the corresponding help can be displayed with the "What's This?" option of the dialog.

##### File Properties Tool

You can view the file properties using Image Properties and General page. This page allow you to see a large image thumbnail, general image and file system informations.

##### Histogram Viewer

If you are interested in the detailed histogram of your photograph you can view it using Image Properties and Histogram page. The histogram for a image shows the amount of each colour that is present and their different amplitudes within the image. If your photograph has a colour cast you might be able to see what is wrong by looking at the histogram.

The Histogram Viewer shows you informations about the statistical distribution of color values in the current image. It is purely informational: nothing you do with it will cause any change to the image. If you want to perform a histogram-based color correction, use the Adjust Levels image plugin. This plugin is part of the DigikamImagePlugins project. For more information about using Plugins in &showfoto; see the Configuration section.

###### The Histogram Viewer in Action

An image can be decomposed into Red, Green, Blue, Alpha color channels. Alpha channel is a Layer in the image that supports transparency (like PNG or GIF images). Each channel supports a range of intensity levels from 0 to 255 (integer valued). Thus, a black pixel is encoded by 0 on all color channels; a white pixel by 255 on all color channels. A transparent pixel is encoded by 0 on the alpha channel; an opaque pixel by 255.

The Histogram Viewer allows you to view each channel separately:

- Intensity: shows the distribution of brightness values.

- Red, Green, Blue: show the distribution of intensity levels for the Red, Green, or Blue channels respectively.

- Alpha: shows the distribution of opacity levels. If the layer is completely opaque or completely transparent, the histogram will consist of a single bar on the left or right edge.

- Colors: shows the Red, Green, and Blue histograms superimposed, so that you can see all of the color distribution information in a single view. In this mode, the histogram foreground color can be choose with Color option.

With the Rendering option, you can determine whether the histogram will be displayed using the Full Image data or only with the current Image Selection. This option can only be enabled, if you have previously selected an image region with editor.

With Scale option, you can change whether the histogram will be displayed using a linear or logarithmic Y axis. For images taken with a digital camera, the Linear mode is usually the most useful. However, for images that contain substantial areas of constant color a Linear histogram will often be dominated by a single bar. In this case a Logarithmic histogram will be more useful.

You can restrict the analysis, for the Statistics shown at the bottom of the dialog, to a limited range of values if you wish. You can set the range in one of two ways:

- Click and drag the pointer across the histogram display area, from the lowest level to the highest level of the range you want.

- Use the spin button entries below the histogram area. Left entry is bottom of range and right entry is top of range.

At the bottom of the Histogram Viewer are shown statistics describing the distribution of channel values, restricted to the selected range. These are:

- The mean.

- The standard deviation.

- The median of the selected histogram portion.

- The number of pixels in the image.

- The number whose values fall within the selected range.

- The percentage whose values fall within the selected range.

With Colors channel mode, this informations are updated with the foreground color selected with Color option.

##### How To Use an Histogram

Histograms are a graphical means to assess the accuracy of an image shown on the screen. The graph represents the 3 regions of the photograph brightness:

- (1) : the shadows-tone on the left.

- (2) : the middle-tone on the middle.

- (3) : the highlights-tone on the right.

###### An Image Histogram in All Colors Mode

The distribution of the graph, where the spikes and bulges are clustered, indicates whether the image is too dark, too bright, or well-balanced.

With an under exposed photograph, the histogram will have a distribution of brightness that tends to be mostly on the left of the graph.

###### An Over Exposed Photograph

With a correctly exposed photograph, the histogram will have a distribution of brightness that will be most prominent near the centre part of the graph.

###### A Correctly Exposed Photograph

With an over exposed photograph, the histogram will have the bulge showing the brightness distributed mostly towards the right of the graph.

###### An Under Exposed Photograph

Important: not all photographs have to exhibit this bulge in the centre part of their histogram. Much depends on the subject of the photograph. In some cases, it might be appropriate for the histogram to show a peak at one end or the other, or both.

The histogram is a reliable way of deciding whether or not a photograph is correctly exposed. Should the histogram show an over or under exposure, an Exposure Correction Tool should be used to fix the photograph.

#### Adjusting a Photograph

##### Cropping a Photograph

###### Manual Crop

Cropping a photograph is a common operation and the &showfoto; makes it very easy. To crop a photograph simple drag a rectangle over the image by holding down the left mouse button and moving the mouse. You will see a wire frame rectangle appear as you move the mouse.

###### The Current Image Selection in Image Editor

When you release the button the area of the photograph that will be removed by a crop operation is darkened. This allows you to get a good view of how your photograph will look once you have cropped it. You can change the size if the cropped area by dragging the corners of the rectangle and you can create a new crop area simply by dragging out another rectangle.

Once you are happy with the crop, click on the The Image Editor Crop Button button on the Tool Bar and the photograph will be cropped. Use the File Save or File Save As entries in the File menu to safe the newly cropped photograph.

###### Proportional Crop

The Aspect Ratio Crop tool goes further. While you are editing digital images, it is often necessary to create a compatible format with, for example, your photo-album or paper formats. If you print an image from your digital camera and then try to put it in your photo album, you may notice that the camera has a different width or height ratio than a normal photographic film format so you need to crop your digital images in a predefined ratio (for example 5:7 or 2:3 which is a standard photo ratio).

###### The Aspect Ratio Crop Tool Image Selection Tab

In the preview area you can size the cropping rectangle by moving the corners with the mouse. It will keep the ratio value set in the bottom of dialog.

In the Aspect Ratio Crop tool settings, you specify the Orientation as Portrait or Landscape. Portrait will always have the larger size assigned to the Height and Landscape to the Width.

Aspect Ratio Crop tool uses a relative ratio. That means it is the same if you use centimeters or inches and it doesn't specify the physical size. For example, you can see below a correspondance list of traditional photographic paper sizes and aspect ratio crop.

Standard Photograph Paper Size | Aspect Ratio Crop
--- | ---
10x15cms 20x30cms 30x45cms 3.5x5" 4x6" 8x12" 12x18" 16x24" 20x30" | 2:3
6x8cms 15x20cms 18x24cms 30x40cms 3.75x5" 4.5x6" 6x8" 7.5x10" 9x12" | 3:4
20x25cms 40x50cms 8x10" 16x20" | 4:5
15x21cms 30x42cms 5x7" | 5:7
21x30cms 42x60cms | 7:10

At the far right of the dialog two buttons are available to move the crop selection automatically to the horizontal or vertical center of the image.

At the very bottom line of the dialog, the Max. Ratio button lets you set the crop area size to the maximum size according with the current aspect ratio settings and orientation.

Aspect Ratio Crop tool remember settings depending of image orientation (Horizontal or Vertical). For each tool session, the current image orientation is used to restore the better settings adapted to the image.

###### Composition Guide

When first looking at an image, the eye of the viewer rarely settles at the centre of the image, but moves instead from the top left to the right, and then from the lower left to the right again. This pattern is most unconscious but has been well-documented. It is probably associated with the western reading pattern. From the photographer's point of view, the goal then becomes to guide the gaze of the viewer to the subject, being aware of the way many people perceive an image.

The Composition Guide settings provides guiding elements to better compose your images. These guides are:

- Rule of Thirds: a grid that divides the picture into thirds in every direction (that makes for 9 parts). These proportions are close to the golden rule and are derived from the field of view of the human eye. They are often used with slight variations throughout a large number of commonly used objects. Within that frame there are precise areas where the important parts of the image should be placed. The same principle is used to determine the position of the horizon and the proportion of ground to sky.

  Many photographers and artists are aware of the Rule of Thirds, where a picture is divided into three sections vertically and horizontally and the points of intersection represent places to position important visual elements. Moving a horizon in a landscape to the position of one third is often more effective than placing it in the middle, but it could also be placed near the bottom one quarter or sixth. There is nothing obligatory about applying the Rule of Thirds. In placing visual elements for effective composition, one must assess many factors including color, dominance, size and balance together with proportion. Often a certain amount of image balance or tension can make a composition more effective.

  ###### Photograph Composition Example Using Rules of Third

- Harmonious Triangles: Harmonious divisions rely on the principle of similarity. Like the Rule of Thirds guide, Harmonious Triangles are another division of the image using a rectangle into equiangular harmonious triangles aligned with the diagonal.

  ###### Photograph Composition Example Using Harmonious Triangles

- Golden Mean: The Golden Mean is a ratio underlying numerous growth patterns throughout nature (from the spiral of a Nautilus shell to the petals of a sunflower), it has an uncanny way of showing up in all kinds of things we deem beautiful.

  The Golden Ratio is the irrational number 1.618033988..., and it's usage dates back to the ancient Egyptians and Greeks who used it in the construction of their temples and pyramids. Artists and architects throughout time have used the Golden Ratio when composing their paintings, buildings, and even photographs, in order to give their creations a sense of natural order and beauty.

  The ratio is inherent in the Fibonacci series: 1, 1, 2, 3, 5, 8, 13, 21, 34 etc., where each succeeding number after 1 is equal to the sum of the two preceding numbers. The ratio formed 1:1.618 is the Golden Mean. A composition following this rule is considered visually harmonious.

  The Golden Mean provide more fluid guidelines when used to compose an image. These guides are listed below:

  - The Golden Spiral guide will increase your odds of getting captivating results in your photographs. As opposed to Rule of Thirds, the Golden Spiral forms a fluid line for the eye to trace through the picture. This style of composition will invite the viewer's gaze into the picture along the line of the spiral, creating a more symmetrical visual flow, and an overall compelling viewing experience.

    ###### Photograph Composition Example Using Golden Spiral

  - One more rule is a Golden Spiral Sections (or Golden Rectangles). These rectangles are used to build the Golden Spiral. There should be something leading the eye to the center of the composition. It could be a line or several subjects. This "something" could just be there without leading the eyes, but it would make its job.

    ###### Photograph Composition Example Using Golden Spiral Sections

  - The Golden Triangles is a derivative of the Golden Spiral discussed above. Its vertices are the midpoints of the sides of the Golden Rectangle. Note that unlike Harmonious Triangles, Golden Triangles aren't equiangular triangle. Placing diagonals along these lines can make an otherwise static subject appear more dynamic.

    When you use Golden Triangles to break up your frame, you're creating an effect dubbed by professional photographic experts named Dynamic Symmetry. Try to keep your focal subject on one of the intersecting points, and place other visual information into the triangles you've already divided out. The result will be a very attractive composition you may not have otherwise attained.

    ###### Photograph Composition Example Using Golden Triangle

  - Like the Rule of Thirds the Golden Sections affects the ratio of a picture size as well as the placement of the main subjects on the photo. This ratio is close to the 35mm ratio, so you don't need to change the size of the photo in most cases. But you need to consider the composition: the main subject should lie on one of the four lines or four intersections (subject's eye for example). Truthfully speaking, these rules are not the same. Rule of Thirds is a simplified version of the Golden Mean.

    ###### Photograph Composition Example Using Golden Sections

The Flip Horizontal and Flip Vertical options can be used to apply flip transformation to the harmonious divisions.

The Color button lets you set the guidelines color. If you have an high color contrast image, the guidelines may become invisible. By this way, you can adapt the color guide to the current image.

##### Resizing a Photograph

If the photograph has the wrong size you can scale it to the size you would like by using Transform Resize tool. Select Transform Resize and adjust the target values. The Resize tool dialog is available below.

###### The Resize Tool Dialog

This image resizing tool use a standard linear interpolation method to approximate pixels. If you want to resizing up a small image with a better quality, try Blowup tool. It is a plug-in available from DigikamImagePlugins project, and you can access it by the Transform Blowup menu entry. See the dedicated Blowup manual for more information.

##### Rotating or Flipping a Photograph

If the photograph is the wrong orientate you can Flip or Rotate it to the correct orientation you would like by using Transform Flip/Rotate tools available in Transform Rotate and Transform Flip menus.

With flipping options, you can flip, turn over, the image horizontally or vertically like a card. With rotating options, you can rotate the image 90 degrees clockwise or counter-clockwise or by 180 degrees. Can be used to change mode to Portrait or Landscape. You can rotate more progressively by using the Free Rotation tool. It is a plug-in available from DigikamImagePlugins project, and you can access it by the Transform Free Rotation menu entry. See the dedicated Free Rotation manual for more information.

##### Fix Red Eye in a Photograph

Red Eye is caused when flash photography is used to take photographs of people. The red is the reflection from the back the eye which can be seen because the pupil can not react quickly enough to the flash. You can correct some of the worst effect of Red Eye by selecting the area of the eye on the photograph, in the same way as described for cropping above. Then select Fix Red Eye Reduction.

###### The Red Eyes Correction Tool in Action

#### Adjusting Sharpness

##### Introduction to Common Tool Dialogs

All Image Editor tools like Sharpen, Blur, Noise Reduction, Refocus, Unsharpen Mask, etc. use a common dialog style that previews the effect before applying the filter to the current image. Below you see the "Apply Texture" tool in action using this common dialog layout:

###### The Apply Texture Tool in Action

- (1): This progress bar indicates the status of filter application on the current image. To the left of it, five buttons allow to select the comparative mode style of the preview area. The modes are:

  - Separate horizontally with duplication. The top area shows the original and the lower one the filter effect for comparison.

  - Separate vertically with duplication. The left area shows the original and the right one the filter effect for comparison.

  - Separate horizontally without duplication. The top area shows the original whereas the lower area shows the filter applied to the continuation of the selected zoom.

  - Separate vertically without duplication. The left area shows the original whereas the right side shows the filter applied to the continuation of the selected zoom.

  - Direct effect preview. The effect preview is applied to all of the selected zoom area.

- (2): The preview selector frame. Click and drag with the mouse on the floating frame to move it on the image. The preview area on the left of dialog is updated accordingly.

- (3): The filter settings area.

- (4): The original area for the zoomed image region. This area is unchanged by the filter. Click and drag with the mouse in this area to move it on the image.

- (5): The target area for the zoomed image region. This area is changed by the filter and presents the actual preview. Click and drag with the mouse in this area to move it on the image.

##### Unblurring a Photograph

If the camera focus is not set perfectly or if the camera is moving when the picture is taken the result is a blurred photograph. If there is a lot of blurring, you probably won't be able to do much about it with any technique. If there is only a moderate amount, you should be able to improve the picture.

In some situations, you may be able to get useful results by sharpening an photograph using the Sharpen tool by the Fix Sharpen menu entry.

###### The Sharpen Tool in Action

You should be careful with this though, or the results will not look very natural: sharpening increases the apparent sharpness of edges in the photograph, but also amplifies noise. The generally most useful technique for sharpening a fuzzy photograph is called the Unsharp Mask. It is a plug-in available from DigikamImagePlugins project, and you can access it by the Fix Unsharp Mask menu entry. See the dedicated Unsharp Mask manual for more information.

###### The Unsharp Mask Image Editor Plugin in Action

##### Reducing Graininess In a Photograph

When you take a photograph in low-light conditions or with a very fast exposure time, the camera does not get enough data to make good estimates of the true color at each pixel, and consequently the resulting photograph looks grainy. You can "smooth out" the graininess by blurring the image, but then you will also lose sharpness. Probably the best approaches, if the graininess is not too bad, is to use the Noise Reduction filter. It is a plug-in available from DigikamImagePlugins project, and you can access it by the Fix Noise Reduction menu entry. See the dedicated Noise Reduction manual for more information.

###### The Noise Reduction Image Editor Plugin in Action

##### Softening a Photograph

Sometimes you have the opposite problem: an image is too crisp. The solution is to blur it a bit: fortunately blurring an image is much easier than sharpening it. Select the Blur Tool, by the Fix Blur menu entry and experiment with the level. The preview windows on the right of the dialogs show the effect of the operation of your photograph.

###### The Blur Tool in Action

#### Correcting Colour

Digital cameras often have problems with lighting conditions and it is not unusual to want to correct the colour, contrast and brightness of a photograph. You can experiment with altering the levels of different aspects of your photographs using the tools under the Fix Colors menu. You can see any adjustments you make reflected in the preview. When you are happy with the results, press Ok and they will take effect.

##### The Color Balance Tool in Action

If your image is washed out (which can easily happen when you take pictures in bright light) try the Hue/Saturation/Lightness tool, which gives you three sliders to manipulate, for Hue, Saturation, and Lightness. Raising the saturation will probably make the image look better. In some cases, it is useful to adjust the lightness at the same time. ("Lightness" here is similar to "Brightness" in the Brightness/Contrast/Gamma tool, except that they are formed from different combinations of the red, green, and blue channels).

When you take pictures in low light conditions, you could get the opposite problem: too much saturation. In this case the Hue/Saturation tool is again a good one to use, only by reducing the saturation instead of increasing it. You can see any adjustments you make reflected in the preview image. When you are happy with the results, press Ok and they will take effect.

##### The Hue Saturation Lightness Tool in Action

The Normalize, Equalize, Auto Levels, and Stretch Contrast available from Fix Auto-Correction menu entry menu will attempt to work out the best color levels automatically. You will need to experiment with the effects of these functions to see what works best with your photograph.

- Normalize: this method scales brightness values across the selected image so that the darkest point becomes black, and the brightest point becomes as bright as possible without altering its hue. This is often a "magic fix" for images that are dim or washed out.

- Equalize: this method adjusts the brightness of colors across the selected image so that the histogram for the Value channel is as flat as possible, that is, so that each possible brightness value appears at about the same number of pixels as each other value. Sometimes Equalize works wonderfully at enhancing the contrasts of an image. Other times it gives garbage. It is a very powerful operation, which can either work miracles on a picture or destroy it.

- Auto-levels: this method maximizes the tonal range in the Red, Green, and Blue channels. It determines the image shadow and highlight limit values and adjust the Red, Green, and Blue channels to a full histogram range.

- Stretch Contrast: this method enhances the contrast and brightness of the RGB values of an image by stretching the lowest and highest values to their fullest range, adjusting everything in between. This is noticeable only with washed-out images and can be a good fix-it tool for bad photographs.

The results of any adjustments you make will not be remembered until you save your photograph.

#### Correcting Exposure

The simplest tool to use is the Brightness/Contrast/Gamma tool. It is also the least powerful, but in many cases it does everything you need. This tool is often useful for images that are overexposed or underexposed; it is not useful for correcting color casts. The tool gives you three sliders to adjust, for "Brightness", "Contrast" and "Gamma". You can see any adjustments you make reflected in the preview image. When you are happy with the results, press Ok and they will take effect.

##### The Brightness Contrast Gamma Tool in Action

If you have the Adjust Levels plugin installed (see the Setup Plugins Section) you will have additional entry in the Fix menu called Fix Colors Levels Adjust. This tool provides an integrated way of seeing the results of adjusting multiple levels and also enables you to save level settings for application to multiple photographs. This can be useful if your camera or scanner often makes the same mistakes and you want to apply the same corrections. See the dedicated Adjust Levels manual for more information.

##### The Adjust Levels Image Editor Plugin in Action

A very powerful way of correcting exposure problems is to use the Adjust Curves plugin available by Fix Colors Curves Adjust menu entry. This tool allows you to click and drag control points on a curve to create a free function mapping input brightness levels to output brightness levels. The Curves tool can replicate any effect you can achieve with Brightness/Contrast/Gamma or the Adjust Levels plugin, though it is more powerful than either one of them. Once again, we refer you to the Adjust Curves manual for more detailed instructions, but the easiest way to learn how to use it is by experimenting.

But this plugin can do more for you, it helps you to improve the tonal quality of your photographs to very finely stepped gray scales. And don't forget that the better the photographs are (good exposure, lossless format, 24 or 32 bit deep) the more you can improve them. Navigate to the "Achieving ultimate tonal quality" section of this instructive page: Tonal quality and dynamic range in digital cameras by Norman Koren. Use Adjust Curves tool to do just the same!

##### The Adjust Curves Image Editor Plugin in Action

#### Special Effects and Filters

By default &showfoto; provides a couple of simple toning filters that you can use on your photographs. Under the Filters menu you will find classic Black and White chemical toning used in analog photography. Color toning changes the monochromatic tint of a basically black and white photograph. When applied it gives the picture a warm, antique feeling. Some examples of colors toning types available in &showfoto; are listed below:

Preview | Type
--- | ---
| Original color image taken in New Zealand landscapes.
| Neutral Black and White: simulate black and white neutral film exposure.
| Black and White with Green Filter: simulate black and white film exposure using green filter. This provide an universal asset for all scenics, especially suited for portraits photographed against sky. Similar to 004 Cokin(tm) Green filter.
| Black and White with Orange Filter: simulate black and white film exposure using orange filter. This will enhances landscapes, marine scenes and aerial photography. Similar to 002 Cokin(tm) Orange filter.
| Black and White with Red Filter: simulate black and white film exposure using red filter. Using this one for creates dramatic sky effects and simulates moonlight scenes in daytime. Similar to 003 Cokin(tm) Red filter.
| Black and White with Yellow Filter: simulate black and white film exposure using yellow filter. Most natural tonal correction and improves contrast. Ideal for landscapes. Similar to 001 Cokin(tm) Yellow filter.
| Sepia Tone: gives a warm highlight and mid-tone while adding a bit of coolness to the shadows-very similar to the process of bleaching a print and re-developing in a sepia toner (typical for your grandmothers photographs). Similar to 005 Cokin(tm) Sepia filter.
| Brown Tone: more neutral than Sepia Tone filter.
| Cold Tone: start subtle and replicate printing on a cold tone black and white paper such as a bromide enlarging paper.
| Platinum Tone: effect that replicate traditional platinum chemical toning done in the darkroom.
| Selenium Tone: effect that replicate traditional selenium chemical toning done in the darkroom.

Many other filters and special effects are available if you have the additional Image Editor Plugins installed (see the Setup Plugins Section), like Film Grain, Rain Drops, Solarize, Charcoal Drawing, etc.

##### The Rain Drops Image Editor Plugin in Action

#### Printing Image

When you want to print the current image, select File Print and you get the standard KDE Print dialog, where you can adjust the settings before printing your photograph.

For more informations about advanced printing settings, please consult KDEPrint manual.

### &showfoto; Configuration

&showfoto; tries to give you as much control on how it works as possible. There are many options that change the behaviour of &showfoto;. To access these settings select Setting Configure &showfoto; from the Menu Bar. The configuration dialog is separated into eight pages. You can change between these pages by clicking on the icons on the left-hand side of the dialog.

#### General Settings

When changes are made to JPEG files and they are saved back to the hard disk the JPEG file must be re-encoded. Each time a JPEG file is encoded a decision must be made on the level of quality that is to be applied. Unfortunately the level of quality applied is not recorded in the image file. This means that &showfoto; cannot use the same quality ratio when saving an altered image as was used for the original image. You can change the default level of quality that &showfoto; will apply when it saves altered images by moving the JPEG quality slider (1: low quality / 100: high quality and no compression).

With PNG compression option, you can reduce PNG image files size. This operation doesn't reduce image quality because PNG usees a lossless algorithm. The only effect is that image data needs more time to compress/decompress. If you have a fast computer you can change this value for to use a high compression factor (1: low compression / 9: high compression).

With Using TIFF compression option, you can toogle to use Adobe Deflate compression algorithm with TIFF image files. This will reduce the TIFF image files size. This has no image quality effect because Adobe Deflate is a lossless algorithm.

By default the editor will use a black background behind photographs when they are displayed. If you prefer a different background colour you can select one here.

Other options manage user interface rules. You can control how &showfoto; will behave when you delete a photograph. You can also turn off the ToolBar and Thumbar when &showfoto; is in full screen mode. Too, you can switch off the display of the splash screen when &showfoto; loads. This may speed up the start time very slightly.

##### The General Settings

#### Plugins Settings

In the early versions of &showfoto; the editor was just a viewer for photographs, but it is rapidly developing into a very useful photo manipulation tool. This dialog allows you to control how &showfoto; will behave.

##### The Plugins Settings

&showfoto; only implements some very simple photo manipulation tools in the core application. For an easy development of more manipulation tools the editor supports a plugin interface. If your distribution has installed the additional &showfoto; plugins they will be listed in the Image Plugins list. You can enable or disable these plugins that you see here.

For more informations about advanced &showfoto; plugins, you can consult the 'DigikamImagePlugins' project at http://extragear.kde.org/apps/digikamimageplugins.

#### Slide Show Settings

Showfoto can slides you photograph to do a nice presentation to your friends. Use this tab to set it properly:

##### The Slide Show Settings

- Delay between images: The length of time between image changes during the slideshow. You can use the slider, type a new value into the field, or use the small arrows to increase or decrease the value. The default is 3 seconds.

- Start with current image: Indicates if the slideshow should start with the first image in the thumbbar or with the image which is currently selected.

- Display in Loop: If you enable this option, slideshow will loop untill you abort it.

- Fullscreen mode: Indicates if Showfoto should switch to full-screen mode when starting the slideshow.

## Menu Descriptions

### The Main Window

#### The File Menu

PgUp File Previous

  Display the previous image of the current list.

PgDown File Next

  Display the next image of the current list.

Ctrl Home File First

  Display the first image of current list.

Ctrl End File Last

  Display the last image of current list.

Ctrl S File Save

  Save the current image if it has been modified.

File Save As

  Save the current image in a new file.

File Revert

  Restore the current image from the original file if it has been modified.

Shift Del File Delete File/Move to trash

  Delete/Move to trash the current image from the current list.

Ctrl P File Print Image

  Print the current image.

Ctrl Q File Quit

  Quit &showfoto; Image Editor.

#### The Edit Menu

Ctrl C Edit Copy

  Copy the current image selection in the clipboard.

Ctrl Z Edit Undo

  Undo the last action applied to the current image using history.

Ctrl Shift Z Edit Redo

  Redo the last action applied to the current image using history.

#### The Image Menu

F3 Image Edit Comments and Tags

  Edit the comments and tags of the currently selected image.

Alt Return Image Properties

  View General Properties, Permissions, embedded Meta-Data, EXIF information, and Histogram of the currently selected image.

Image Apply Texture

  digiKam image plugin to apply decorative texture to the current image.

  See the dedicated Apply Texture manual for more information.

Image Add Border

  digiKam image plugin to add a decorative border around the current image.

  See the dedicated Add Border manual for more information.

Image Insert Text

  digiKam image plugin to insert text in the current image.

  See the dedicated Insert Text manual for more information.

Image Template Superimpose

  digiKam image plugin for apply a template to the current image.

  See the dedicated Template Superimpose manual for more information.

#### The Fix Menu

Fix Colors Brightness/Contrast/Gamma

  Exposure correction of the current image by Brightness, Contrast, or Gamma adjustments.

Fix Colors Hue/Saturation/Lightness

  Color correction of the current image by Hue, Saturation, or Lightness adjustments.

Fix Colors Color Balance

  Color correction of the current image by Red, Green, or Blue adjustments.

Fix Colors Auto-Correction

  Automatic color correction of the current image by an histogram manipulation.

Fix Colors Invert

  Invert image colors.

Fix Colors Levels Adjust

  digiKam image plugin to adjust levels manually on the current image.

  See the dedicated Adjust Levels manual for more information.

Fix Colors Curves Adjust

  digiKam image plugin to adjust curves manually on the current image.

  See the dedicated Adjust Curves manual for more information.

Fix Colors Channel Mixer

  digiKam image plugin to mix color channels on the current image.

  See the dedicated Channel Mixer manual for more information.

Fix Colors White Balance

  digiKam image plugin to adjust white color balance on the current image.

  See the dedicated White Balance manual for more information.

Fix Blur

  Focus error correction of the current image by a blurring operation.

Fix Sharpen

  Focus error correction of the current image by a sharping operation.

Fix Red Eye Reduction

  Red Eye correction using the current selection of the current image.

Fix Unsharp Mask

  digiKam image plugin to operate an Unsharp mask on the current image.

  See the dedicated Unsharp Mask manual for more information.

Fix Lens Distortion Correction

  digiKam image plugin to correct lens distortion of the current image.

  See the dedicated Lens Distortion Correction manual for more information.

Fix Restoration

  digiKam image plugin to reduce artefacts on the current image.

  See the dedicated Photograph Restoration manual for more information.

Fix Inpainting

  digiKam image plugin to remove unwanted area on the current image.

  See the dedicated Photograph Inpainting manual for more information.

Fix Noise Reduction

  digiKam image plugin to reduce the noise on the current image with using a Despeckle filter.

  See the dedicated Noise Reduction manual for more information.

Fix Anti Vignetting

  digiKam image plugin to correct vignetting of the current image.

  See the dedicated Anti Vignetting manual for more information.

Fix Refocus

  Image Editor plugin to refocus the current image.

  See the dedicated Refocus Photograph manual for more information.

Fix Hot Pixels Correction

  Image Editor plugin to remove hot pixels on the current image.

  See the dedicated Hot Pixels Photograph manual for more information.

#### The Transform Menu

Shift 1 Transform Rotate 90 degrees

  90 degrees rotation of the current image.

Shift 2 Transform Rotate 180 degrees

  180 degrees rotation of the current image.

Shift 3 Transform Rotate 270 degrees

  270 degrees rotation of the current image.

Transform Flip Horizontally

  Horizontal flip of the current image.

Transform Flip Vertically

  Vertical flip of the current image.

Transform Crop

  Crop the current image to the current selection.

Transform Resize

  Resize the current image to the appropriate factor or dimensions.

Transform Aspect Ratio Crop

  Crop the current image using an constrained aspect ratio.

Transform Blowup

  digiKam image plugin to blow up a photograph without less image quality.

  See the dedicated Blowup manual for more information.

Transform Shear

  digiKam image plugin to shear the current image.horizontally or vertically.

  See the dedicated Shear Tool manual for more information.

Transform Free Rotation

  digiKam image plugin to rotate the current image by any angle in degrees.

  See the dedicated Free Rotation manual for more information.

Transform Perspective Adjustment

  digiKam image plugin to adjust perspective of the current image.

  See the dedicated Perspective Adjustment manual for more information.

#### The View Menu

Ctrl+ View Zoom In

  Increase the zoom factor on the current image.

Ctrl- View Zoom Out

  Decrease the zoom factor on the current image.

A View Zoom AutoFit

  Set the zoom factor for adapting the current image size to the Image Editors window size.

View Histogram

  Display superimposed histogram under current image.

#### The Filters Menu

Filters Black and White

  Apply Black and White filter to the current image.

Filters Raindrops

  digiKam image plugin to add Rain Drops on the current image.

  See the dedicated Rain Drops manual for more information.

Filters Infrared Film

  digiKam image plugin to simulate infrared film on the current image.

  See the dedicated Infrared Film manual for more information.

Filters Oil paint

  digiKam image plugin to simulate Oil Painting on the current image.

  See the dedicated Oil Paint manual for more information.

Filters Emboss

  digiKam image plugin to Emboss the current image.

  See the dedicated Emboss Image manual for more information.

Filters Solarize Image

  digiKam image plugin to Solarize the current image.

  See the dedicated Solarize Image manual for more information.

Filters Distortion Effects

  digiKam image plugin to apply distortion special effects on the current image.

  See the dedicated Distortion Effects manual for more information.

Filters Add Film Grain

  digiKam image plugin for to adding Film Grain on the current image.

  See the dedicated Film Grain manual for more information.

Filters Blur Effects

  digiKam image plugin to apply blurring special effects on the current image.

  See the dedicated Blur Effects manual for more information.

Filters Charcoal Drawing

  digiKam image plugin to simulate Charcoal Drawing on the current image.

  See the dedicated Charcoal Drawing manual for more information.

#### The Settings Menu

Ctrl Shift F Settings Full Screen Mode

  Toggles the graphic interface to full screen mode.

Settings Configure Shorcuts

  Configure the &showfoto; image editor shortcuts.

Settings Configure Toolbars

  Configure the &showfoto; image editor toolbars.

Settings Configure &showfoto;

  Lauch &showfoto; configure dialog.

#### The Help Menu

&help.menu.documentation;

Additionally &showfoto; Image Editor offers this item:

Help ImagePlugins' Handbooks

  Launch the KDE help interface with the &showfoto; Image Editor plugins handbooks.

## Credits and License

digiKam logo

Program copyright 2004-2005, &showfoto; developers team

- Renchi Raju renchi_at_pooh.tam.uiuc.edu: Coordinator, Main Developer.

- Caulier Gilles caulier_dot_gilles_at_free.fr: Co-coordinator, Developer, French Translations.

- Joern Ahrens kde_at_jokele.de: Developer.

- Tom Albers tomalbers_at_kde.nl: Developer.

Documentation copyrighted by:

- 2004-2005

  - Gilles Caulier caulier_dot_gilles_at_free.fr

  - Gerhard Kulzer gerhard at kulzer.net

All Pictures copyrighted 2004-2005 by Gilles Caulier caulier_dot_gilles_at_free.fr.

&underFDL;

&underGPL;

## Installation

### How to Obtain &showfoto;

&showfoto; is a part of digiKam project and the website is at http://www.digikam.org. Please check it regularly to get the latest news about &showfoto;. &showfoto; can be obtained in binary and source format from http://sourceforge.net/project/showfiles.php?group_id=42641.

Also you can checkout the digiKam source code modules from KDE Extragear SVN repository like this:

        % svn co -N svn://anonsvn.kde.org/home/kde/trunk/extragear/graphics
        % cd graphics
        % svn up digikam
        % svn co svn://anonsvn.kde.org/home/kde/branches/KDE/3.5/kde-common/admin

The last SVN snapshoots can be downloaded at this URL ftp://ftp.kde.org/pub/kde/unstable/snapshots/.

### Requirements

In order to successfully use &showfoto;, you need the following:

- AutoConf >= 2.5

- AutoMake >= 1.7.0

- KDE 3.x

- imlib2 >= 1.2.0

- libkexif >= 0.1

- libtiff >= 3.5.x

- DigikamImagePlugins >= 0.7.3 (optional)

KDE can be obtained from KDE Home Page.

libkexif can be obtained from http://www.digikam.org.

DigikamImagePlugins can be obtained from http://extragear.kde.org/apps/digikamimageplugins.

Most likely your distribution vendor might already have packaged and provided these packages.

### Compilation and Installation

In order to compile and install &showfoto; on your system, type the following in the basedirectorys of the libkipi and digikam module distributions:

        % export WANT_AUTOCONF_2_5=1
        % export KDEDIR=KDE_installation_dir_on_your_system
        % export
        PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/path/to/installation/lib/pkgconfig
        % make -f Makefile.cvs
        % ./configure
        % make
        % su
        % make install

#### Important Notices

Stage 3 is required if you are installing libkexif in a non-standard location, and you must let pkg-config know about their paths.

More specific compilation and installation options can be passed to the configure script. Use `./configure --help` on the command line to view these options.

Use --enable-debug=full option with configure script for to provide a full informations bug report.

Because &showfoto; depends on libkexif, you must build or install this library before you build &showfoto;.

Since &showfoto; uses autoconf and automake you should not have trouble compiling it. If you run into problems please report them to digikam-users@kde.org.

&documentation.index;