Author Topic: Pantone color discrepancy  (Read 2656 times)

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Offline Eric Summers

Pantone color discrepancy
« on: May 19, 2021, 09:27:33 am »
I can't get specific, but I have come across several Pantone colors that are not the same when compared to Illustrator. And it isn't lighting environment related, I'm talking about the RGB values.
I drag a particular Pantone+ Solid Coated v4 color swatch onto my material, click on the material color and look at the RGB values. Then, in Illustrator, I open the Pantone+ Solid Coated swatch library and drag the same Pantone onto a rectangle as the fill. Then I switch the color mode to RGB and compare the values.
Can someone explain this discrepancy? I would think Pantone colors should be the same across any program. I suppose I could pull a random Pantone number to show the difference if needed.

Offline DMerz III

Re: Pantone color discrepancy
« Reply #1 on: May 19, 2021, 05:35:59 pm »
Not 100% sure - but wondering if the gamma corrected checkbox in the color palette settings would make a difference here.

e; Not the answer you want to hear I am sure, but for me, when I need to match a pantone color, I always tell myself I will have to handle it in post. Again, not ideal, and you bring up a valid point for sure - it should be consistent program to program.

Offline Eric Summers

Re: Pantone color discrepancy
« Reply #2 on: May 20, 2021, 05:30:48 am »
Not 100% sure - but wondering if the gamma corrected checkbox in the color palette settings would make a difference here.

e; Not the answer you want to hear I am sure, but for me, when I need to match a pantone color, I always tell myself I will have to handle it in post. Again, not ideal, and you bring up a valid point for sure - it should be consistent program to program.

Hmm, I might have to see if the gamma corrected checkbox does anything. Thanks for the lead David!

And yes, definitely not what I want to hear - my post skills aren't the best.  :D

Offline Fred B

Re: Pantone color discrepancy
« Reply #3 on: May 26, 2021, 09:26:47 am »
I'm pretty sure this is due to a potential color space difference. Illustrator (I believe) uses Adobe RGB and Keyshot uses sRGB.

All color starts with XYZ tristimulus values and is calculated out from there. XYZ's go to Linear RGB, then to non-linear RGB, and finally Red Green Blue (The 0-255 values). In the conversion to RL GL BL (linear RGB) values it uses a 3x3 matrix that is dependent on the Color Space and reference white. Even though they have the same reference white the matrix values are different.

A good resource for the math behind this is
http://www.brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html 

Offline andy.engelkemier

Re: Pantone color discrepancy
« Reply #4 on: August 31, 2021, 06:52:04 am »
Isn't it more complicated than that?
First, the discrepancy is going to be there because illustrator does the conversion at M2 colors because Adobe assumes if you're using pantone, it's for print. M1 colors are D50 illuminant, where M2 are UV excluded.
If you go to pantone's site, you can get the RGB conversions of any of the colors as sRGB.

Also, is the XYZ chart correct? sRGB doesn't use a normal gamma. It's a gamma of 1.0 near black, then peaks the rest of the curve around 2.4, so I'm not sure how you could use a standard transform matrix to change values without taking the complex curve into consideration.

Online Synje Andersen

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Re: Pantone color discrepancy
« Reply #5 on: September 01, 2021, 12:06:46 am »
Hi

Andy is right to a point.

While this could be gamma related, the reason is probably a lot simpler (gamma would not just influence the Pantone colors but other colors as well).

Adobe programs do use the D50 White Point as far as we know, since they are considered print focused applications.

KeyShot is not print focused and as such does not use the D50 but the D65 White Point, which corresponds to a color temperature of approximately 6500° K, the average daylight in Western/Northern Europe at midday.

We recently added the same information to the manual.
https://manual.keyshot.com/manual/materials/color-library/

Best Regards
Synje

Offline DMerz III

Re: Pantone color discrepancy
« Reply #6 on: September 10, 2021, 08:39:36 am »
So Synje - are you suggesting the solution here for those of us who need to match colors in Illustrator is to use the colors as sRGB from Pantone's website?

I'm still a bit confused on the proper workflow. For example;

Let's say, I get an artwork file from the client - they've got an expectation of what the label should look like based on what they see in Illustrator. My render should match those colors as close as possible with as little manually adjustments as possible. What would you suggest is my workflow?