From: ehill@world.std.com (ed) Subject: Re: TECH: Color Correction of Real Images Date: Mon, 18 Mar 1996 20:37:51 GMT Organization: ed's 3d stuff Hendrik-Jan van Veen wrote: hello folks looks like a great project. i envy you. don't envy whoever scans and organizes all of those photo's though. apologies in advance if you know this stuff already but some parts may be helpful... <...stuff deleted...> >Questions: >: Is there any way in which we could use the color histogram of each >picture and the grand average histogram to equalize the colors over all >pictures? Similarly for contrast and luminance? >: Can anyone think of a different approach? you may be working harder than you have to. indoor and outdoor films in their place, should simulate our cognitive adjustment to different color temperature in the lighting. i strongly suggest that you shoot on overcast days. not as dramatic but the detail preserved is far greater. more like the eye sees as it adjusts while going from light to shadow. when you shoot each scene, the film will only record within a certain luminosity. if those working your cameras are carefull, most of your contrast management will be a function of properly exposing and processing your film. you may wish to shoot grey cards on the first few frames in each roll and have "snip tests" done when the photographer is unsure of the outcome. if using chromes i'd overexpose and underdevelop a half to a full stop to hold more detail at both ends of the films curve. test and talk with the lab. since our eyes adjust to changes in lighting, the similarity in luminosity from one place to another shouldn't be perceived as an artifact. >: Is there anyone around who has experience with similar problems? me >: Are there any publications on this topic? not to my knowledge. although there are some good books on sensitometry. that and the handbook of reprographics might help. >We have high-performance Silicon Graphics machines, PowerMacs and if >necessary we could buy WindowsPc's as well. >Any input is highly appreciated. >Please send your comments to my personal email address as well. i wish you best of luck on the project. regards ed