On Thursday 26 January 2006 12:07 pm, Cory Papenfuss wrote: snip > Ooops. I guess I wasn't clear. The matrix I was referring to is > the LUT in the profile, not the "use color matrix" checkbox from within > UFRAW. I think I finally (and recently) figured out what that's supposed > to do. It enables the RGB->RGB transform matrix from dcraw (who got it > from Adobe) *before* it does any of the color management stuff. In other > words, it's only really useful if you're going to do a default sRGB > non-color-managed conversion. For any real profiles (like the ones I've > been playing with generated by LPROF), the checkbox should be off.
Thanks for clearing this up. > > > I should add that profiles generated by LPROF (without local convergence) > > and ProfilePrism give results that are only very slightly different. > > Subjectively the PP profiles are very slightly more saturated and that is > > only difference that I can detect. Overall tonality, white balance, > > shadow detail, highlight detail ... are almost identical. Of course it > > would be a simple matter for a UFRAW user to make adjustments in how much > > saturation (or contrast, shadow detail, brightness) the profile will add > > to the final result when profiling with LPROF by adjusting the saturation > > level in UFRAW in the opposite direction when converting the IT8 target. > > So with a slight adjustment I could make the LPROF and PP profiles give > > subjectively identical results. > > I don't trust myself to do much subjective adjustments. :) The > profile I got with LPROF without local convergence yields a very similar > result to that which I ripped out of a BibblePro install. That's what > I'd been using so far. One of the features of ProfilePrism is that it allows you to tweak your profiles to change contrast, saturation, gamma (labled brightness in PP) and color balance. This is useful in PP for doing printer profiles since it uses a scanner as it's "measurement tool" and needs this to compensate for the scanner. These same settings can also be used when profiling a camera or scanner. But when I use PP I set these to not make any changes (default settings). I was mainly pointing out that the differences between the results from LPROF and PP (with default settings) are very small and that LPROF/UFRAW users can influence the profile much like a PP user can but that this is done in a slightly different way. I think that the results I am getting without doing this are actually sightly better than PP as I think the default setting in PP give a very slightly over saturated result. snip > > The matrix view (NOT gamut view) is the most telling. Pretty > funky on the broken profiles, but very smooth on the non-local convergence > ones. Exactly, this will be very helpful when working on fixing this as I will be able to tell if a code change has made this worse or better or not changed anything. > > -Cory ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=103432&bid=230486&dat=121642 _______________________________________________ Lcms-user mailing list Lcms-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/lcms-user
