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Paul and Friends The blue CCD channel is generally the weakest of the three color channels for the sensor. On especially negative film the blue channel is the densest or darkest channel. Thus there is a conflict between the least sensitive channel needing to scan the most difficult darkest film densities on negative films. This both why a yellow posterization cast exists on a lot of CCD scanning of negatives and why the scanner engineers like to turn up the blue channel gain, integration time and sensitivity in blue. Yet if they turn up the sensitivity it also pushes the CCD into a noise condition of over modulation and yes banding in the blue channel distinguishable from the others. This whole process is a catch 22 which is very frustrating to CCD scanner designers, engineers and software developers. We need better CCDs or PMT (photo multiplier) / drum scanners to avoid these issues. Phil Lippincott www.aztek.com "Paul D. DeRocco" wrote: > I don't think it could be, because then it wouldn't be able to do superfine > mode with a single line. It sounds like it's three lines, each of which has > RGB sensors, whose only purpose is to be able to capture three scan lines at > a time. I don't think the fact that there are three lines has anything to do > with the fact that there are three primary colors--they could have used a > four-line CCD and made it four times as fast as superfine mode. > > Or maybe I'm missing something. > > -- > > Ciao, Paul D. DeRocco > Paul mailto:pderocco@ix.netcom.com > > > From: orafe.bustin@verizon.net > > > > On 9 Apr 2002 at 21:37, gary wrote: > > > > > So it is tri-line but monochrome (i.e. no color mask), right? > > > > yup, you got it. > > - > Turn off HTML mail features. Keep quoted material short. Use accurate > subject lines. http://www.leben.com/lists for list instructions. - Turn off HTML mail features. Keep quoted material short. Use accurate subject lines. http://www.leben.com/lists for list instructions.
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