i've found a way to get gray values from rgb:
gray = (red*77 + green*151 + blue*28) shr 8

what are the respective values for converting an rgb to sepia? (acdsee does it as an effect)
Posted on 2004-01-24 19:10:32 by ploptor
Hi :)
Actually you can't get sepia from that formula, since it assigns the same value to the three RGB components -that always gives some shade of gray.
This is not exactly what you want, but it might help anyway:

Posted on 2004-01-25 15:37:58 by QvasiModo