Scanning underexposed negs

[Martin Francis]

I have a set of 6x6cm negs that need scanning. They are all underexposed
(actually I believe underdeveloped) quite significantly. My Canon D2400UF
scans them well enough for sharpness, and can pull plenty of detail from the
highlights, but the shadows become blocky when I try to lighten them.

Will a dedicated film scanner (LS9000, Scan Multi Pro) provide better shadow
detail than a flatbed? How about a Flextight scan, and if so which would be
better? While i'd be willing to buy or hire a film scanner, I know of a
place which scans using a Flextight... but at a rate that is 1/8 of the
price of a film scanner for one 12-shot roll.

While i'm here, are there any opinions on the Epson F3200 film scanner, as
compared to the more expensive models?

Martin

 

[birdman]

A better flat bed with a greater density range should be sufficient.
Also there are ways to combine scans done to optimize different parts of the
negative using layers in a program like Photoshop.

 

[gazza95]

Hi Martin

You may find that there are actually 2 issues when trying to get
reasonable results from underexposed negative film. Firstly I think you
will find that underexposed negative film has a much coarser grain
structure than when correctly exposed. If I remember correctly the
larger grains respond better at low exposures. This you should see in
any print that was made from the negative at similar enlargements. What
size do you want to print? When I have a "bad" negative I accept that I
will not be able to print at 300 dpi from the maximum scanner
resolution so scan at the maximum, use a filter like median to remove
most of the noise/grain , apply unsharp mask to clean the edges, and
then print at a smaller size.

Secondly as Erik said you need to ensure that you use the correct
scanning exposure. You do need to get the maximum exposure without any
clipping of any colour channels. This I do by scanning a piece of truly
unexposed film e.g. between frames and checking a histogram showing all
three channels seperately. Then use this fixed exposure for the film.
On your final scan you should see no clipping at either end of the
scale.


hope this helps a little
gary