>>I did find one adjustment so far. The last line should be:
>>
>>

>>	pair2Y = rgb(pair2Yred, pair2Ygreen , pair2Yblue )
>>

>>
>>This fixes that line but still results in another color than the one expected.
>
>While reading this thread I was about to propose something similar, but not using the difference (specially that your pair2 plus the difference may go over 255). I'd go with
>
>newR2=newR1*(oldR2/oldR1)
>
>and same for G and B.
>
>You could maybe achieve a similar result by taking the average of the quotients for each R, G and B.


Ok, but newR2 may go over 255 as well