From: pandeng@telepath.com (Steve Schafer (TeamB))
Subject: Re: RGB to CMYK and viceversa
Date: 18 Mar 1999 00:00:00 GMT
Message-ID: <3716384c.153502595@90.0.0.40>
Content-Transfer-Encoding: 7bit
References: <7cqg2l$8lq11@forums.borland.com>
Content-Type: text/plain; charset=us-ascii
Organization: TeamB
Mime-Version: 1.0
Reply-To: pandeng@telepath.com
Newsgroups: borland.public.delphi.graphics

On Thu, 18 Mar 1999 10:22:42 +0100, "Marco De Toni"
<mdt@dedalomedia.it> wrote:

>Does anybody tell me a more accurated way  to convert CMYK to RGB and
>viceversa (es. like Adobe Photoshop)

I'm going to assume that your RGB values range from 0 to 255, and your
CMYK values range from 0 to 100.

RGB -> CMYK

 C := 100 - Round(100 * R / 255);
 M := 100 - Round(100 * G / 255);
 Y := 100 - Round(100 * B / 255);
 K := C;
 if M < K
   then K := M;
 if Y < K
   then K := Y;
 C := C - K;
 M := M - K;
 Y := Y - K;

CMYK -> RGB

 R := 255 - Round(2.55 * (C + K));
 if R < 0 then
   R := 0;
 G := 255 - Round(2.55 * (M + K));
 if G < 0 then
   G := 0;
 B := 255 - Round(2.55 * (Y + K));
 if B < 0 then
   B := 0;

-Steve