On 5/1/2014 4:56 PM, Darrin Cardani wrote: It’s converting them between color spaces. I believe that the values you send to -addColorParameter: are in sRGB because that’s the color space that the user interface operates in. But your filter will process them in either linear or gamma-corrected RGB (depending on your -properties) with Rec. 709 primaries rather than sRGB primaries. _______________________________________________ Do not post admin requests to the list. They will be ignored. Pro-apps-dev mailing list (Pro-apps-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/pro-apps-dev/site_archiver%40lists.a... This email sent to site_archiver@lists.apple.com But if I say I work in rec709 shouldn't it assume my default colors are also in rec709 and not convert them for me? It seems wrong to munge my default colors and give me different ones. Can you give me an implementation of the reverse of your function so I can pre-reverse-munge my defaults (when I define the parameter) so I get back what I gave you initially?