wdr@wang.com (William Ricker) (06/27/91)
>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. ***
strobl@gmdzi.gmd.de (Wolfgang Strobl) (06/28/91)
wdr@wang.com (William Ricker) writes: [...] > I don't know if there is any easy way to disable the inboard >lamp(s) without voiding warranty. There is no switch, and the documenation doesn't describe the interface. Logitech offers some kind of programmers toolkit for the scanner, but I don't know how much it costs. Perhaps it allows switching the light independent of the scanning function. > Did you try full range of contrast settings of the scanman? Yes, but in vain. The contrast knob has a range from 1-10, but there is not much difference between 1 and 3, for most of my negatives. The picture gets lighter when scanned using position 1, but lack any details in the shadows - it simply becomes gray in gray. I get bad results with negatives where the base material which carries the the sensitive layer has a color (i.e. gray, not white) itself. > 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. Yes, this works very well - I bought the Scanman mostly because of the included Windows based Ansel software. >>Scanning color negatives didn't work at all. > I wouldn't expect it to; the built in light source is monochrome. Hm. Scanning color positives works better that I expected. The light source is pure red, so everything looks like seen through a red filter, which gives an view which is quite unnatural. But the effect on paper pictures seems to be weaker than if you do the filtering when you take the picture. My main problem when scanning color paper positives is that a picture which seems to be perfectly sharp on paper may look blurred after scanning. Wolfgang Strobl