Hello Thomas http://www.imapro.com/scanners.htm#QCS-3200%20Flatbed%20Scanner� is the A3 Flatbed scanner I own, Ive got 3 actually,I bought 2 used ones as spares when the importers, Imapro UK, closed their doors for business some years ago. It does indeed use 3 fluorescent tubes is not entry level and cost �15,500 in 96 and connects through a GBIP interface. D max is not in today's ball park though the scans are just as usable now as they were when I bought it !
Your point re the CCD deficiencies is noted Regards Michael Wilkinson. 106 Holyhead Rd, Ketley, Telford, Shropshire. England .TF1 5DJ 44 (0) 1952 618986. www.infocus-photography.co.uk For Negatives & transparencies from digital files ________________________________________________ ----- Original Message ----- From: "Thomas Holm / Pixl" > Michael Wilkinson wrote: > > > Thomas , > > Surly a scanner with separate RGB light sources will perform correctly > > Short answer Nope. > > Long answer: > > Separate RGB light sources? > Mind explaining that? > > If I understand you right you mean three light sources filtered to emit > energy in specific spectra which, when combined, will be similar to the spd > curve of D50 light? > First, to the best of my knowledge there is no such thing on the market at > all. The "usual suspects" for making D50 light is filtered tungsten, or > pulsed Xenon. Certain light box manufacturers produce tubes that will yield > 5000K, but not D50 spectra - most are not even close and therefore prone to > metamerism. If you plot the spd curves of any fluorescent tube or a monitor > you'll see peaks and valleys, which doesn't mean as much when viewing > things, but mean the world when measuring. > > Also I doubt you'd find three light sources in an entry level product. The > only products I know using this technology are Printers that expose paper > with Lasers (Lambda and the likes), and even those have severe problems > reproducing certain colours. FYI a Lambda laser is $5-7000. > > A scanner (non PMT) GENERALLY function by having a sensor which is 3 pixels > wide which are filtered with red green and blue one pixel wide. > A fluorescent light tube is lilluminating the area the scanner is passing > over. > > The reason for using fluorescent light is one of cost and convenience: > 1) It's important to have an even light across the entire surface (those of > you shooting reprographic work know that setting up 3 light sources in a > confided space won't easily give you even light over a surface). > 2) LCD sensors are extremely sensitive to temperature fluctuations - > particularly increases in temperature, which are inherent with most > continuous type light sources. > > But even if you could produce three light sources that gave you D50, you'd > still have the deficiencies from a CCD sensor, and the Observer metamerism > inherent in those. > > > Best Regards, > Thomas Holm / Pixl Aps > > - Photographer, Educator, Colour Management Consultant & Seminar speaker > - Remote Profiling Service (Output ICC profiles) > - www.pixl.dk � Email: th[AT]pixl.dk > -- > > > > =============================================================== > GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE > --- > > =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
