Help Scanning Photos on Glass

I have 2 "photographs" on glass and if you view them from the face side
they are positive photos (about 50 yrs old) that are *printed* on the
back of the glass and then *painted* over black. they are scratched and
in a poor state and i have been asked to do someting with them.
My scanner is a Canoscan N124ou and the inside of the lid is a white
colour so when i scan i just see an area of black.

pmj...

I *think* (though I may well be wrong) [*1] that the Canon N1240u
Scanner uses LEDs, rather than a "Cold Cathode" as it's light source?
The LiDE Series uses LEDs, rather than Cold Cathode tubes.

[*1] In fact I'm almost certain that it *does* use LEDs as the Light
Source.

The upshot of that is that the Light that the LEDs is nowhere near
as bright as that from a Cold Cathode Tube (which is a bit like
a Fluorescent tube), so it's not likely to be very good for Scanning
the sort of things you are doing.

Try a Scanner that uses a Cold Cathode Tube.
Also, when you do the Scan, use the Scanner's Twain Interface,
to Adjust the "levels", *before* Scanning, so as to get as much
Detail as possible in the Dark areas.

The Canon Twain Interface has some quite good Adjustments available.

& then in a Graphics Editing Package ,you may be able to Adjust
the Levels even more.

The Colors will never be as good as the original though, simply cos
there's not enough Light.

Have a look at this Site, which has loads of Helpful Info about how
to get the best from a Scanner...

TIA

BoyPete...

Perhaps the light is being refracted through the thickness of the glass? Can
you photograph them instead?

Old Grizzly...

If i backlight them i have thought of that Pete, but its a much more
lengthy process.

Old Grizzly...

What i just posted was a load of *****cks! there are no transparent bits
coz its just like a photo mounted behind glass. Huh :-) so the light
would have nothing to shine thro LOL

BoyPete...

I guess reflection might still be a problem. Sounds like a 'specialists'
job. Would be a shame not to do something to preserve the images though.

Wrinklie One =?iso-8859-1?Q?=A9?=...

Did you have them right way up (or down) in the scanner??? It should be
just the same as scanning a photograph, illuminated from underneath ???