Scanning thin negatives and Vuescan

  • Thread starter Thread starter Roger Halstead
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Roger Halstead

I have a fair number of available light shots that are... well...dark.
When I scan them they come out very coarse and grainy. It looks as if
VueScan tries to set the exposure according to the dark areas and
bring out the detail. I've tried locking the exposure, but that
doesn't seem to help on these negative strips.

The same thing happens with shots of distant aircraft. The colors are
wrong until the aircraft becomes a significant part of the image. (or
there are enough clouds).

Any thoughts?

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
 
I have a fair number of available light shots that are... well...dark.
When I scan them they come out very coarse and grainy. It looks as if
VueScan tries to set the exposure according to the dark areas and
bring out the detail.
Click to expand...

VueScan's default philosophy seems to be to pull as much information from
the film as it can, and let you decide what to do with it. It can't
easily tell the difference between grain and actual low-level detail,
after all.

You can probably reduce the effect of the grain either by raising the
VueScan's black point somewhat (so as to submerge the grain in the
blackness), or by postprocessing in Photoshop or whatever. In Photoshop,
you can use either the Levels tool (to raise the black point as in
VueScan) or with the Curves tool (to make the grain darker and less
contrasty).
 
Delete- said:
I have a fair number of available light shots that are... well...dark.
When I scan them they come out very coarse and grainy. It looks as if
VueScan tries to set the exposure according to the dark areas and
bring out the detail. I've tried locking the exposure, but that
doesn't seem to help on these negative strips.

The same thing happens with shots of distant aircraft. The colors are
wrong until the aircraft becomes a significant part of the image. (or
there are enough clouds).

Any thoughts?

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
Click to expand...
Take a look at the histograms on these shots, especially the shots of the
distant aircraft. I think you will find that the scanner histogram (top
histo) will look like a spike corresponding to the fairly narrow range of
brightness in the sky, yet the output histogram (bottom) will be
stretched (too much) to fit the available dynamic range. manually grab
the black and white points on the top hist and expand them until you get
approximately the picture you want. (hint if you use "lock image colour"
you will see individual rgb white and black points to adjust).

Bruce Graham
 
Roger Halstead said:
I have a fair number of available light shots that are... well...dark.
When I scan them they come out very coarse and grainy.
Click to expand...

They probably are grainy, because only relatively few grains (the
"larger" ones) received enough exposure to become processable into dye
clouds :-(
Also the random statistical properties of Photons become easier to
see.
It looks as if VueScan tries to set the exposure according to the
dark areas and bring out the detail.
Click to expand...

Let VueScan determine the maximum allowable exposure without clipping,
it'll reduce noise. Autoexposure will work fine on underexposed
negatives. Depending on your scanner, multi-scanning may help a bit.
I've tried locking the exposure, but that doesn't seem to help on
Click to expand...
these negative strips.

That's consistent with the exposure determination, it is probably
already close to optimal. All you can do on under/low exposure
negatives is scan with diffuse light, if the scanner allows to control
that, and use a program like Neat Image to reduce the graininess
(don't overdo it, deliberately leave "some" graininess in the image).
The same thing happens with shots of distant aircraft. The colors are
wrong until the aircraft becomes a significant part of the image. (or
there are enough clouds).
Click to expand...

That's to be expected if the average image tones have a bias towards a
dominant color (blue). What works best in such shots is to first crop
the subject very tight (especially if there is some white in the crop
area you can also right-mouse-button click on neutral tones), set
brightness and such, then lock the image color. Now re-crop to the
final dimensions and scan.
It will all work better if you follow the Advanced Workflow
suggestions for locking the exposure and filmbase color first, because
in a tight aircraft crop it will be hard to automatically determine
those parameters.

Bart
 
I think the distant aircraft shots are suffering from a different
problem than the dark shots. With respect to the aircraft shots,
check your Filter tab and make sure that "Restore Fading" is
unchecked. I had had a HUGE problem with images where blue sky
dominates (e.g., hot air balloon races) until I discovered the effect
of "Restore Fading" and use of "Lock Image Color". Bart's suggestion
of zooming in to do the color balance, lock image color, recrop and
scan is a good one! I hadn't thought of that, so I learned something
new today. (Thanks, Bart.)

Bill
 
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