Just found out that I am still subscribed to this ML but I simply do not receive anything (incl. my email password reminder). I don't have the slightest idea why... Anyway, to answer Jan-Peter:
> Wolf, if some people would be interested on such thinks, would you like > to distribute also such charts additional to your photographic produced > charts ? Why not. I simply do not see how this can be done cost effective as you would need to produce very small amounts of targets on a very large number of different setups. After all we need a cost effective solution for these customers (otherwise we better buy a spectrometer). But there are a number of things we should not forget: there are many cases where costs or technical reasons do not allow producing scanner targets using the wanted materials. And even simple cases like yours can turn out tricky: you are talking of a 4-7 ink colors printer that produces shades by halftoning. So in reality, you still only have 4-7 inks and the scanner does simply see every dot with all it's problems. So halftoning might matter not only on the print, but also on the scan. Another problem is, as Graeme noted, that we are talking about converting >3 dimensional output space back into a three dimensional Lab value. As a result, the separation original used for printing does matter as the scanner for instance can't easily tell a true black ink from a mixed one. So I see a number of advantages in building a database and trying to add the spectral data of scanner, ink and everything else that is easy to get/use. It's not perfect but should get us very close. Graeme: I agree, spectral characterization of a scanner most likely needs more than three dyes. I was surprised about the IEC 61966-8 standard for spectral characterization of scanners. This standard uses only a target simlar to the IT 8.7 target (same layout... just more highly saturated colors in order to help the calculation). There is even free source and binary code available from http://www.ite.rwth- aachen.de/Inhalt/Forschung/AixSpecScan/scan_cal.html implementing the standard. So, there is a standard and tools to get experience. I bought the standard some time ago and even added spectral data for my targets in hope some applications turns up using the standard so I could produce them. But so far, I haven't even found some info on the practical experience of using the standard nor had I time to do my own tests. As you know, there are actualy a number of articles available from SPIE and others handling spectral characterization of scanners. Anybody out there with experience about spectral characterization of scanners and the accuracy achived willing to share his info? Otherwise I am sure to find some time to at least provide the necessary targets and data for tests. With kind regards Wolf Faust -- Wolf Faust Tel: +49-69-5486556 mailto:[EMAIL PROTECTED] Fax: +49-69-95409598 http://www.coloraid.de Mobile: +49-179-6924769 ------------------------------------------------------- SF.Net email is sponsored by: Discover Easy Linux Migration Strategies from IBM. Find simple to follow Roadmaps, straightforward articles, informative Webcasts and more! Get everything you need to get up to speed, fast. http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click _______________________________________________ Lcms-user mailing list Lcms-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/lcms-user
