How to get good scans of dark slides?

I have a large collection of old slides from the 60s and 70s. I bought
an HP Scanjet 4890 scanner and have been scanning them into digital
form, TIFFs. A few are dark, underexposed. When you preview these
slides with the HP scan utility preview function, ones that are dark
will not be "boxed", and so will not be scanned. I have found that I
can manually "Box" them in with the mouse, defining the area of the
slide. This will make the software scan it....but I gather if it
doesn't "box-in" a slide, it is telling you it is too dark for a good
scan. And sure enough, the ones I had to manually scan are terrible.
However, I can view them decently on my old carousel projector. I
suspect that this is because the projector bulb is a whole lot
brighter than the light source in the lid of the scanner. I suppose
there is nothing I can do to get a better scan, since I can't crank up
the brightness of the scanner light source. Also, there does not
appear to be a way to increase the sensitivity of the sensor CCD. So I
suppose that these will have to be professionally scanned by a
service. But can any pro scanning service handle underexposed slides,
and at least to some extent compensate for underexposure so that they
are brightened up? recommendation where to send them?

Sounds like a job for a slide converter and a very
strong back-light.

Chris

Dedicated film scanners do not have this problem, but be aware that such
scans usually require some post - processing. It might be cheaper to
purchase a used or economic model slide and film scanner than have a
professional service do it for you. Example for a workable dedicated scanner
(better than your flatbed but not approaching more professional models like
Nikon) in performance would be the Plustek 7200. It will not deliver the
promised resolution, but for the kind of slides you have 3600 dpi is already
overkill.


"geronimo" schrieb im Newsbeitrag
...
I have a large collection of old slides from the 60s and 70s. I bought
an HP Scanjet 4890 scanner and have been scanning them into digital
form, TIFFs. A few are dark, underexposed. When you preview these
slides with the HP scan utility preview function, ones that are dark
will not be "boxed", and so will not be scanned. I have found that I
can manually "Box" them in with the mouse, defining the area of the
slide. This will make the software scan it....but I gather if it
doesn't "box-in" a slide, it is telling you it is too dark for a good
scan. And sure enough, the ones I had to manually scan are terrible.
However, I can view them decently on my old carousel projector. I
suspect that this is because the projector bulb is a whole lot
brighter than the light source in the lid of the scanner. I suppose
there is nothing I can do to get a better scan, since I can't crank up
the brightness of the scanner light source. Also, there does not
appear to be a way to increase the sensitivity of the sensor CCD. So I
suppose that these will have to be professionally scanned by a
service. But can any pro scanning service handle underexposed slides,
and at least to some extent compensate for underexposure so that they
are brightened up? recommendation where to send them?

"geronimo" schrieb im Newsbeitrag
...
I have a large collection of old slides from the 60s and 70s. I bought
an HP Scanjet 4890 scanner and have been scanning them into digital
form, TIFFs. A few are dark, underexposed. When you preview these
slides with the HP scan utility preview function, ones that are dark
will not be "boxed", and so will not be scanned. I have found that I
can manually "Box" them in with the mouse, defining the area of the
slide. This will make the software scan it....but I gather if it
doesn't "box-in" a slide, it is telling you it is too dark for a good
scan. And sure enough, the ones I had to manually scan are terrible.
However, I can view them decently on my old carousel projector. I
suspect that this is because the projector bulb is a whole lot
brighter than the light source in the lid of the scanner. I suppose
there is nothing I can do to get a better scan, since I can't crank up
the brightness of the scanner light source. Also, there does not
appear to be a way to increase the sensitivity of the sensor CCD. So I
suppose that these will have to be professionally scanned by a
service. But can any pro scanning service handle underexposed slides,
and at least to some extent compensate for underexposure so that they
are brightened up? recommendation where to send them?



Have you used the manual controls to adjust the gamma, etc. or are you
relying on auto?