Hi Graeme Thanks for giving this your attention - much appreciated. On the profiles I have had a chance to run so far the hook issue is gone. I'll run some more profiles shortly but it looks like problem solved. Thanks again Phil phil tanner wrote: > I think I may have found a bug in ArgyllCMS 1.5.1. > The profiles created with Argyll all have a nasty hook in the absolute > colorimetric rendering as tone tends towards black. OK, this turns out to be a side effect of me adding some smoothing to the out of gamut clipping values. Simplest fix is for me to turn the filtering off, since it didn't seem to provide much benefit that I could see. Fix will be in V1.6.0, and I've uploaded an MSWin 32 bin executable of the beta here: <http://www.argyllcms.com/colprof_win32_exe.zip> Graeme Gill.