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Why is the difference between RGB->CMYK values so large?
Posted: 19 Feb 2005, 15:14
First off i found your software very interesting since im the one responsible for making decicsion for buying new printers. But what im trying to figure out is why are the conversion from RGB->CMYK so very different from Adobe Photoshops algo. ? Thanks for any response you can give me.
Se this example: R:180, G:187, B:194
APFILL: C:8%, M:5%, Y:2%, K:21%
PHOTOSHOP: C:30%, M:21%, Y:18%, K:0%
Posted: 19 Feb 2005, 18:49
You can read about APFill CMYK here
Q: Why results in CMYK in Photoshop and results in APFill differnt although in RGB they are the same?
A: Photoshop convert RGB to CMYK with self development algorithm. So algorithms in Photoshop and for example in Corel Draw are different. APFill uses formal convertion algorithm. If you want get average CMYK like in your editor, you can take average RGB color in APFill and convert it to CMYK in your graphic editor.
Q: I set RGB color in Photoshop and fill area with it, then I measure color density with APfill. But average RGB in APFill results and RGB color in Photoshop are diffrernt.
A: The fact is that Photoshop and Corel Draw convert colors according to Monitor Color Profile. If you remove Monitor Color profile then results in Photoshop and in APFill will the same.
Posted: 19 Feb 2005, 19:46
Thanks for the fast answer! I must admit i didnt read the faq, wich i usually do before asking questions. Guess i forgot it this time..
But thanks for your help!
Posted: 19 Feb 2005, 19:49
I forgot to ask you something.. Why is there a question mark (?) in the CMYK tab? shouldnt it just say C for Cyan?
Posted: 20 Feb 2005, 08:33
nibly wrote:I forgot to ask you something.. Why is there a question mark (?) in the CMYK tab? shouldnt it just say C for Cyan?
Yes, we will fix this bug, thanks.