GreTag MacBeth Color Checker - additional uses?

[jerryreed]

I am a giclée maker, and my primary responsibility to the artist is to match the color of a known art piece. To make my business profitable, it is helpful to move as quickly to an exact color match as possible. In pursuit of this end, I have been investigating the utility of a tool that I current utilize, but imagine could be used still further with the effect of speeding up my workflow.

The GreTag MacBeth Color Checker, publishes for each of the squares that make up the GT CC luminance and color value stated in the LAB Mode.

Since it is part of my practice to utilize the CC to set the exposure and to neutralize the possibility of color casts, utilizing the GT CC, the card is included in every job as a reference.

I am looking to learn if anyone has worked out a way to use COLOR BALANCE or CURVES adjustment layers to match the Lab values to those found in a photo of the GT CC. If I were able to develop a workflow that would consistently provide very close matching, it seems that would speed up my workflow.

If anyone wishes to offer color matching suggestions that are not directly in response to the question that I have posed please feel free to jump in.

Thanks in advance,

Jerry Reed

 

[Ben Rubinstein]

I've just started using the gretag chart with the new DNG Profile Builder to make colour accurate profiles for use with ACR/LR. What I've found is that it also manipulates the black/white point relative to the lighting in the profile so that not only the colour but also the brightness/black point/saturation are also perfect. Wasn't expecting that actually. Hey, it's free software, why not give it a try?

 

[Bob]

I have found that matching exactly all colorchecker values is difficult, partially since the rgb values published are relative to D65 illumination. I have found that Adobe dng calibrator and white balance settings get me close but not really exactly on target with the illuminants I have available to me.
When exposed with flash, which is what I have, the results are pretty close but most sensors I have tried tend to produce colors with more saturation than the target, even after calibrating. I think that some additional saturation tweaking is required and perhaps the use of a bandpass filter to remove UV and IR.
Good luck, and please report back what you find.
-bob

 

[jerryreed]

Gentlemen,

Thank you for your suggestions and expressions of continuing interest in this subject. As I uncover additional, please know that I will share it here.

Jerry

 

[Lars]

Jerry, I hope that you are aware of that any recipes you cook up using Photoshop for color adjustments are only valid for one specific working color space. Tools in Photoshop like curves are generally not color-aware, it's just math with pixel values.

This goes for published RGB values of the CC as well - without a color space as reference (and illumination reference, as Bob mentioned) the numbers are just numbers.