Xref: utzoo comp.graphics:18874 rec.photo:22941 Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!wang!wdr From: wdr@wang.com (William Ricker) Newsgroups: comp.graphics,rec.photo Subject: Scanning negatives (Re: Can handheld scanners scan BACKLIT images?) Message-ID: Date: 27 Jun 91 14:53:22 GMT References: <2835@umriscc.isc.umr.edu> <4993@gmdzi.gmd.de> Organization: Wang Labs, Lowell MA, USA Lines: 40 >wdr@wang.com (William Ricker) [that's me] writes: >>1. Some scanners have an adjustable contrast knob (eg Logitech ScanMan 256). >> twisting this may force it to ignore one source or the other. Try it. ... >> for twisting the contrast knob, as double filtering in grey areas will >> seriously shift the contrast curve (as I found out photocopying B&W >> tone transparencies). strobl@gmdzi.gmd.de (Wolfgang Strobl) writes: >While putting the negative strip on a white paper and scanning it with >contrast set to dark and dpi to 400 works quite well for normal and >light negatives, it doesn't work at all for pictures where the interesting >details are in the darker parts of the negative. The light passing through the darker areas (hilights of original) are being filtered twice by the silver halides (or dyes) in the negative, so this is expected. A later responce suggested using incandescant, maybe DC, lighting on a light box (flourescents flicker noticibly to the scanner). I don't know if there is any easy way to disable the inboard lamp(s) without voiding warranty. Did you try full range of contrast settings of the scanman? I assume you used the Ansel software that comes with the scanner to do negative reversal for previewing. Did you try adjusting the contrast while viewing? Alt-View, Show B/C gives you a pair of sliders to control brightness and contrast. This will let you explore the image's highlights and dark recesses separately. You can also selectively lighten and darken regions, if you want to emulate burning in and holding back digitally. >Scanning color negatives didn't work at all. I wouldn't expect it to; the built in light source is monochrome. This is an additional area where a scanner lobotomy to work with transmitted light would be a win; although I don't know what the spectral sensitivity of the sensors is -- they might be tuned to the inboard lamps, they might not be. -- /s/ Bill Ricker wdr@wang.wang.com "The Freedom of the Press belongs to those who own one." *** Warning: This account is not authorized to express opinions. ***