Home | Monitor Tab | Preferences Tab | Profile Checker | Profile Identification | Camera/Scanner Profile Parameters | Display Profile Parameters | Monitor Values Dialog | Set Gamma Dialog | Install Reference File Dialog | UFRAW Tutorial |

# Monitor Tab Help Window

LProf is an open source application that creates ICC profile for cameras, scanners and monitors/displays.

### Create a Monitor Profile

LProf can work in two different modes to generate a monitor profile. The "advanced" mode, that gives accurate profiles by using hardware devices like X-Rite DP92 or GretagMacbeth EyeOne, and the "simple" mode, that allow to you build reasonably accurate profiles without any additional hardware.

### Building a monitor profile: a coarse approximation

Let's build our first monitor profile to check how all this stuff works. We don't need great accuracy at this point. We want to create an approximation, just to visually check if all is going OK. First start LProf. Since we need only a coarse profile on the "Monitor Profiler" tab select the radio button labeled: "Build a coarse profile, giving approximate values". This is selected by default. We do not need any hardware measurements at this point only a few visual adjustments. Press the button labeled: "Enter monitor values". You will see the monitor values dialog.

#### Step 1: Set contrast

In order to obtain maximum performance, we need to adjust the physical monitor controls. Set contrast to near maximum, (yes, near maximum. This is the gain of the monitor and we need as much gain as the monitor can deliver).

#### Step 2: Set Gamma and Black Point

Now select the "Set Gamma and Black Point" button. This dialog will help you to set both the gamma and black point for your monitor.

#### Step 4: Set White Point

For information on setting monitor White Point see Rough Monitor Values.

#### Step 5: Set Primaries

Next adjustment is setting the primaries. For information on setting Monitor Primaries values see Rough Monitor Values.

#### Step 6: Make Final Settings and Create Profile

Now you can use the "Profile Identification" dialog to fill in the info about your monitor. Although this is not strictly required, it could prevent a lot of confusion when you have more than a couple of profiles. It is important to include unique information in the "Description" field of this dialog since this information is used by many applications, including LProf, to list profiles for users. Now we are ready to generate our profile. We must specify the output filename just like you did when creating a camera/scanner profile. For the name, we could use something like "CoarseMonitor.icm". Type in the name and then proceed to generate the profile by pressing the "Create Profile" button. If all is OK, the status console will show "Profile DONE!". Let's now check how well the profile is working by eye. Do this is basically the same way you proofed your scanner profile.

###

### Building a Monitor Profile: Using a Hardware Measurement Device.

Starting with LProf version 1.11.5 display calibration and profiling hardware measurement devices are now supported. LProf supports the following hardware devices for calibrating and profiling displays:

- GretagMacbeth EyeOne Display
- GretagMacbeth EyeOne Display LT
- GretagMacbeth EyeOne Display 2
- GretagMacbeth EyeOne Pro
- GretagMacbeth Spectrolino
- X-Rite DTP-92
- X-Rite DTP-94

Supported USB devices are automatically detected and will be listed in the Select Instrument: combo on the Display Calibration and Measurement dialog. Devices that use a serial port need to be configured in the Serial Measurement Device Setup area on the Preferences tab. Most of the supported devices are USB devices.

The first step to create an accurate profile is the calibrate and measure the monitor. This is done either by using one of the measurement devices supported by LProf or by using an external program with some other device to calibrate and measure the display. This document will describe both ways of doing this but will put more emphases on using a supported measurement device because this will allow you to achive a better display calibration.

#### Calibrate and Measure Using a Supported Measurement Device

This is handled by the Display Calibration and Measurement dialog so please refer to the documnetation that covers it for more detail. That dialog will allow you to do a number of important operations that will result in your display being properly adjusted (calibrated) and measured so that a profile can be created.
When you have completed running the Display Calibration and Measurement dialog two measurement files will have been created. These will contain the video card gamma table data, called a Calibration Sheet, and the profiling measurement data, called a Measurement Sheet. The Calibration Sheet data will be used to create a VCGT tag in the profile which will be used to load the video card gamma tables to get the correct gamma and also to get the right color balance for the whole tonal range of the display. The Measurement Sheet data will be used to create the color look up tables in the profile. Unlike most commerical profiling software LProf does not come with it's own gamma loader but X11 users can use xcalib, Windows users can use either xcalib or the Windows Color Control Panel Applet and Mac users can use ColorSync.
These files will appear in the Measurement Sheet and Calibration Sheet entry boxes that appear below the "Use externally generated files" radio button. When using an LProf supported measurement device these are grayed out and can not be changed by a user.

#### Create the Profile

First in the "Output profile file", select a new file name for your profile. Please use a name that ends in .icm or .icc since these are the standard file extenstions that all software expects for profiles. Next use the "Edit Profile Identification" button and fill the info fields if you want (again, this is recommended). It is important to include unique information in the "Description" field of this dialog since this information is used by many applications, including LProf, to list profiles for users. I will use this sample to present another utility, the profile checker. Since the profile checker can understand advanced tags, we want to include all information in the profile, so select the "Edit Profile Parameters" button, and make sure to select "Verbose, store anything" in the "Profile verbosity" group. Next press then press the "Create Profile" button. A new profile will be created. We will check now how accurate this profile is. Start the profile checker dialog selecting the "Profile Checker" button. The profile checker is a tool for inspecting some of profiles internal data. In our case, we want to check the accuracy.

#### Create a Measurent File Outside of LProf

To do this you need to create a IT8/CGATS measurement sheet file containing XYZ measurements for several RGB combinations for your monitor. A sample file of this kind can be found in <prefix>"/share/lprof/data/pics" directory. Where <prefix> is the installation location of LProf. If you are running LProf from the build directory these files will be located in the data/pics directory of the source code tree. The file is called "sRGB.IT8" and it contains measurements for an ideal sRGB monitor. Use this file as a template for creating your own monitor measurement sheet file. You need to change the XYZ values to those read by your measurement device. Don't put any Lab values, just RGB and XYZ values. Please keep the RGB values the sRGB.IT8 has. Optionally, you can use more patches to assure consistent color reproduction, but make sure to include at least the ones in sRGB.IT8. In the <prefix>"/share/lprof/data/pics" directory you will also find "display patches.tiff". This file contains color patches that correspond to the values used in sRGB.IT8 and it can be used to measure the these RGB values from your display. Note that a large number of gray patches are needed. You can also add as many as you wish, with more gray patches, you will get better linearization control curves. You must specify at least 16 gray patches.
To create a profile select the "Use externally generated files" radio button. This will allow you to select or enter file names for both the Measurement Sheet and the Calibration Sheet. Creating a Calibration Sheet by hand is well beyond the scope of this documentation and requires some fairly complex computation that will make this an impossible task for most users without the use of specialized software such as LProf. Therefore please leave the Calibration Sheet entry empty unless you can somehow create a Calibration Sheet file. But the resulting profile will not contain any calibration data in the form of a VCGT. A measurement file created using the process in the last paragraph can be used to create a profile by selecting it as your Measurement Sheet and following the steps in "Create the Profile" (above).

Copyright © 1998-2007 LProf. All Rights Reserved.

Copyright © 2007 LProf | Trademarks | LProf 1.11.5