Convert a list of RGB values to CMYK

[jdonnelly]

I have a list of RGB values that I would like to convert to CMYK values. I've located some help that will requires the values be entered manually. I would like to read the list and convert.

Thanks!

 

[Rick Rothstein]

Can you tell us where your RGB values are located and tell us where you want the CYMK values to be placed and whether you want a formula solution or VBA solution?

 

[Rick Rothstein]

Where did you go? You were online when I asked my question. Okay, I'll assume your RGB values are in separate columns (Columns A, B, C for R, G, B respectively) and that your output is to go in Columns D, E, F, G (for C, M, Y, K respectively). Also, I am assuming Row 1 is used for headers. With that said, put these formulas in the indicated cells and copy them down...

D2: =(1-$G2-A2/255)/(1-$G2)

E2: =(1-$G2-B2/255)/(1-$G2)

F2: =(1-$G2-C2/255)/(1-$G2)

G2: =1-MAX(A2/255,B2/255,C2/255)

Make sure to format the cells in Columns D, E, F, G as Percentage with zero decimal points.

 

[Jon Peltier]

Rick, we need to prevent to prevent #DIV/0 errors for black, that is, RGB(0, 0, 0). It might be as simple as

D2: =(1-$G2-A2/255)/(1-IF($G2=1,0,$G2))
E2: =(1-$G2-B2/255)/(1-IF($G2=1,0,$G2))
F2: =(1-$G2-C2/255)/(1-IF($G2=1,0,$G2))

 

[Rick Rothstein]

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Good catch Jon. If I had noticed that problem, I probably would have opted to use IFERROR...

D2: =IFERROR((1-$G2-A2/255)/(1-$G2),)
E2: =IFERROR((1-$G2-B2/255)/(1-$G2),)
F2: =IFERROR((1-$G2-C2/255)/(1-$G2),)

 

[Jon Peltier]

Yep, that works, too.

 

[jdonnelly]

Rick and Jon, Thank you both for your assistance with this issue. Rick, you assumptions regarding how the columns are setup are correct. We now have a solution in place for this challenge.

Thanks!