RGB to CMYK Problem

Hi Doug ,

I can explain it like this: I use this method in Excel when converting RGB values to CMYK  codes.

The RGB color model works with values ranging from 0 to 255.
To convert RGB to CMYK, I first normalize the RGB values to a scale of 0 to 1:

R' = R / 255 G' = G / 255 B' = B / 255

Then, I calculate the K value (black component) using the following formula max value:

K = 1 - max(R', G', B')

After that, I calculate the C, M, and Y values with these formulas (as long as K ≠ 1)

C = (1 - R' - K) / (1 - K) M = (1 - G' - K) / (1 - K) Y = (1 - B' - K) / (1 - K)

This is how the formulas are structured in Python, and I created mine based on these standard formulas. However, I'm currently facing an issue: the CMYK values generated by Excel and those shown in Adobe applications are different.

Now I'm unsure which one is more accurate.
If I need to work according to Adobe's system, then I should find or develop a new formula for Excel that matches Adobe's output.
On the other hand, if the values I get in Excel are correct, then I need to align Adobe applications accordingly.