# Jpegencoder - to CMYK

**URL:** https://forum.kirupa.com/t/jpegencoder-to-cmyk/293053
**Category:** Uncategorized
**Created:** [July 22, 2009, 4:00pm UTC](https://forum.kirupa.com/t/jpegencoder-to-cmyk/293053 "2009-07-22T16:00:01Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![partimer](https://avatars.discourse-cdn.com/v4/letter/p/f1d935/32.png) [@partimer](https://forum.kirupa.com/u/partimer)
#### Post date: [July 22, 2009, 4:00pm UTC](https://forum.kirupa.com/t/jpegencoder-to-cmyk/293053/1 "2009-07-22T16:00:01Z")

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I’ve got a project where the I need to encode a jpeg in CMYK and I was wondering whether any of you you knew of any means to do this?

I’ve found a cracking script that converts individual rgb ‘points’ to CMYK values but I’m getting stuck when trying to amend the RGB2YUV function in the standard (adobe) jpegEncode – obviously this has to change to allow the four values but should I use another colour profile other than YUV?

```auto
  private function RGB2YUV(source:Object, xpos:int, ypos:int, width:int=0, height:int=0):void
    {
        var pos:int = 0;
        for (var y:int = 0; y < 8; y++)
        {
            for (var x:int = 0; x < 8; x++)
            {
                var P:uint = getPixel32(source, xpos+x, ypos+y, width, height);
                var R:Number = Number((P>>16)&0xFF);
                var G:Number = Number((P>> 8)&0xFF);
                var B:Number = Number((P )&0xFF);
                YDU[pos]=((( 0.29900)*R+( 0.58700)*G+( 0.11400)*B))-128;
                UDU[pos]=(((-0.16874)*R+(-0.33126)*G+( 0.50000)*B));
                VDU[pos]=((( 0.50000)*R+(-0.41869)*G+(-0.08131)*B));
                pos++;
            }
        }
    }

```

I’ve amended the ‘paramers’ of the jpeg creation so that 8 bits/4 components are specified but have hit a brick wall…

Any help would be fantastic.

Many thanks in advance,

Partimer