Is your software applying your display profile?


When trying to debug your colour management workflow, one of the problems you may face is to discover whether or not your software is actually using the display profile that you have carefully made and then associated with your monitor screen. There are three aspects to this problem—

  1. Has the calibration information from the profile been loaded into the monitor, so that it is now “calibrated”?
  2. Is your application software paying attention to the display profile and translating the colour information in your photo into the colour space of your monitor?
  3. If you have a dual- or multi-monitor set up, is your application software using the profile for the screen it's running on, or is it always using the profile for screen 1?

This page gives you the tools to answer questions 2 and 3.

A stunt, “whacked” or weird display profile

The changes made by a display profile are often quite small, so it's hard to tell if it is in effect. To make it easy to tell, we need a display profile that really makes a big difference to the image. So I created a profile called pvf_display_weird1.icc that does make a big difference.

This profile has standard gamma 2.2 tone response curves, so it is no use for tackling question 1 above. But it has a very non-standard XYZ-to-RGB conversion matrix: this matrix swops the red and green colourants. Using this profile basically makes red things in your photos look green, and vice versa. But it does so if and only if the application you are using to display the photo is using the profile to convert from the colour space of the photo (perhaps sRGB or AdobeRGB) into the color space of the display profile.

Installing the test profile

Just install the profile in the normal way. These instructions are for Windows 7; you'll have to adapt them if you have some other version of Windows.

  1. To download the profile left click this.
  2. Find the file on your disk — it's called pvf_display_weird1.icc — right click on it, and click on “Install profile”. This will copy the profile to a Windows system folder (usually C:\Windows\System32\spool\drivers\color). It also makes it visible in Control Panel.
  3. Run Control Panel, click on Color Management.
  4. You should see a screen like—

  5. If you have several monitors, use the “Device” drop-down to select the desired one.
  6. Make sure that “Use my settings for this device” is ticked.
  7. Click on “Add...”.
  8. Find the profile named “pvf_display_weird1”, click on it, then click OK.
  9. You should now see the weird profile listed under “Profiles associated with this device:”. Click on the profile, then click “Set as Default Profile”
  10. If you have configured Windows 7 to load your profiles, that's it. If not, you now need to reboot (actually this isn't strictly necessary but it's prudent to ensure that the profile has been loaded in the usual manner).

Using the test profile

Find a photo that has some clean reds and greens in it, and make sure that it has a profile embedded in the jpg file. If you haven't got one, download this one which has sRGB embedded.

Display this photo on your screen using whatever application you want to test. For example, you could open the photo in an image editor such as Photoshop, GIMP or IrfanView. Or you could open it in a web browser such as Internet Explorer, Chrome, Firefox or Safari.

If the application does not apply display profiles properly, the photo should look normal. If it does apply display profiles properly the photo should be displayed with reds and greens interchanged.

If you have a multi-monitor set up, you can try setting the weird profile on one particular monitor and then seeing if the application notices it. You should find that Photoshop and Lightroom notice the profile and change the appearance of the displayed photo as you move their windows onto or off the relevant monitor. At present, in 2011, you should find that Firefox and Safari only notice the profile if it is set for screen 1; if screen 1 has the weird profile, then these two browsers will show photos with reds and greens interchanged whatever monitor they are running on. Internet Explorer 8 won't notice the profile at all. Internet Explorer 9 should, but I don't know what it does in a multi-monitor set up.

And finally...

I won't say “Have fun!” because colour management really isn't fun. It was not for nothing that Scott Kelby entitled his chapter on colour management Anger Management. But I hope that this technique may help to translate anger into progress.

Peter Facey, Winchester, England
20110224 originated