I have a calibrated monitor. To verify the calibration I compared picture of a color checker vs. my color checker passport. They look very similar. The first problem is that the same picture looks a little different in Light Room vs. other viewers for example DPP or Micrsoft Viewer. The picture of color checker is more close to the reality in the Light Room than DPP.
That's normal. Lightroom is a color managed application, it actually uses the monitor profile you created to compute the proper colors to display. DPP and Microsoft viewer are not color managed, they don't actually use the profile, so their colors are off. The only benefit programs like that get from calibration is the "white point" setting.
A calibration program and calibrating device (EyeOne Display, Spyder, etc) do two things:
- calibration, which consists of getting the monitor to a "useful" state where it's "white point" matches a desired viewing situation. What that means is that the color of "white" that the monitor produces is equal to a specific color.
The monitor is "emissive", it's a "light maker". The only thing that affects the monitor is its own settings. If the computer tells the monitor to display a particular color, that's what it does. If you turn off the room lights, that color is still on the monitor.
Your passport is "reflective". It's not on the monitor. Its color is affected by the color of the room lights. Make the room lights warmer (more orange) and the passport looks warmer. Turn off the room lights, and the passport goes away.
So, if you told the calibrating program a color that doesn't match the room lights, the passport doesn't match the image seen on the screen.
There's another problem. There are multiple pictures of the Checker floating around the internet (as BAK mentioned). The only one that actually works for what you're trying to do is one that's computer generated (instead of photographed) in the L*A*B color space. Any ColorChecker picture in sRGB, Adobe RGB, or any picture that's a real "picture" (shot with a camera or scanned on a scanner) of the ColorChecker will be wrong. Plain and simple.
The second problem is that when I compare picture of the color checker taken with my 50D, the color are very lighter. I’m using a Sekonic L358 and also check the white patch to make sure the exposure is correct. I also corrected the white balance by clicking on a gray patch. If the exposure is reduced by about 1 stop the colors are close to real but with correct exposure they are lighter. I have tried different camera profiles and found that Adobe Standard gives the best result surely after one stop underexpose.
Of course. Part of that is probably simply the ColorChecker image you're using. If it's not LAB, the brightness
will be wrong , guaranteed. 100%.
Even if it is LAB, if your calibration process didn't include adjusting the monitor brightness to exactly match the room lighting, the checker on the screen won't match the passport. If your lighting is dimmer than what you calibrated the monitor to, the image on the screen is too bright. An "extreme" example: turn off the room lights. The passport is now in the dark, and the image on the screen is many stops brigher than the passport.
Calibration really takes more than will fit in one little post, but I've given you a start.
wizfaq
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Rahon Klavanian 1912-2008.
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