Advanced Display Profiling

If you’ve linked to this sub-article from the main Colour Management 101 post, then you’re probably looking for information on getting your display profile even more accurate.  The information in the main article will work quite well and with some profiling solutions with feature limited software, may be the only way to go.

For those who are doing more serious printing or other commercial work and who have profiling hardware with more advanced software, the following discussion may be useful.

In an ideal world, you’ll have a print booth set up in your office next to your monitor so you can set a print up and compare side by side with what’s on the display.  A print booth is a device with a highly colour corrected light source (5000K, or D50) that allows you to adjust the brightness of the light to match the brightness of your display.  I say highly colour corrected because adjustments to the brightness of the light won’t affect the colour temperature as can happen with light sources that aren’t high quality.  Now, not all of us have a print booth.  In that case, you’ll need to make some workarounds.  I don’t have a print booth.  What I do have is a 5000K fluorescent bulb that shines through a fairly thick, frosted glass shade.  This gives me a good light for viewing prints.  As good as a print booth?  No.  But the lighth source is a constant, which is important.  The light sits on a corner of my desk where I can set a print next to it for viewing and my monitor sits about a foot away from the print at such an angle that at a comfortable viewing distance, I can look from one to the other without having to turn my head much but I can’t just move my eyes.

The software for my Spyder2Pro allows me to adjust the profiling conditions of my monitor to a significant degree.  I can choose my white point, black point, colour temperature and even adjust the gamma curve.

You’ll want a good reference image to do this type of comparison and profile tweaking.  This classic reference image will work well.  I found it on Gary Ballard’s website.  There are two targets in the ZIP folders along with license agreements for using the targets.  Either target will work.

To do this more advanced display profiling, you need to print out the target properly at the image resolution of 300 ppi.  Place the target in your viewing light and make a visual comparison to the monitor based on your current profile settings for colour temperature, black point and white point.  Note any differences in terms of contrast and warm/cool tone to the display relative to the print.  In order to do a proper comparison, you need to be in soft proof mode on your display.  Why?  Because you’ve printed the target as is without making any soft-proof adjustments to compensate for the paper so you need to be viewing the image on your display as it was printed without corrections.

Once you’ve made this comparison, go back into your display calibration software and invoke the advanced settings.  If the display looks cool compared to the print, adjust the colour temperature down slightly.  If the display looks warm relative to the print, increase the colour temperature in the profiling software slightly.  Increments of 250K will be a good start.  If the print looks dark relative to the display, adjust the target white point (display luminance or brightness) down from its current setting.  Do the opposite if the display looks dark compared to the print (a less likely outcome).  With the new settings, reprofile your display, adjusting the settings to reach the new targets.  Once this is done, make another comparison to the print.  If there are still differences, work through the process again.  It may require a few iterations to get it right.

If you have a proper print booth, you can adjust the brightness of the booth to match the display.  This will help.  Then you’re concerning yourself only with the colour temperature of the display.  Adjusting the colour temperature can have a visual impact on brightness as well.

If you’re using a non-adjustable light source like me, then you need to work with both the display brightness and colour temperature.  This complicates things a little but it will work in the end.

While I started my calibration at D65 and had a black point of .7 and a white point of 115.3 (as suggested by the software) on my LCD monitor, what I ended up with after working through the process was a colour temperature for the monitor of 6250, a black point of .54 and a white point of 115.6. These aren’t significant differences but just enough to give me a better visual match between my prints and my monitor.

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