n cook wrote:
Other than cleaning mirrors & lenses anyone any ideas on how to bring the
exposure level up to get black on light grey rather than black on almost
equally dark black background.
Anyone tried translucent thin but very white plastic sheet of some sort
overlaying the original. ?
Reducing the exposure masking increases the exposure but whites out the fine
details.
The paper has gone very brown from air bourne SO2/SO3 , neutralising the
paper with alkali improves things but tends to lighten the black image so no
further forward as far as contrast.

Hi...

Please do yourself a favour and don't even think about cleaning
mirrors and lenses...

You haven't mentioned the scanner maker or model, but I suspect
what you're looking to do is scan them in either your choice of
either black and white or grayscale. Suspicion is that you'll
find grayscale more to your liking, but experiment yourself to
decide.

You mention wanting to bring the exposure level up; not exactly sure
what it is you mean, but what you really want to "play around with"
is the gamma.

Here's how I'd do it: Find the whitest white (note that white *doesn't*
mean white, but rather an absense of colour. Set that to 100%
Next find the blackest black (again, not black but dark with an
absense of colour). Set that to 0%. Next move the gamma to
your eyes pleasure, making the mid-tone grays look good.

Take care.

Ken