Topic: How to scan color transparencies.
I bought an old Heidelberg Linoscan 1450 scanner together with VueScan and would like to scan my 4×5″ negatives/slides. There are several problems to solve:
1. The scanner has some bad pixels, so I get stripes in the scanned image (solved by downloading and installing the newest version and clicking on “calibrate”).
2. How to get rid of newton rings?
I started with a dry scan and asked myself what side should be up: The base or the emulsion?
The first thing I noted was that the film bends. According to my observation it bends the edges upwards, when the emulsion side is up. Since I don’t have a film holder, I put the emulsion side down. This enables me to fix the film with tesa film on the scanner, where the tesa touches only the base side. This apparently solved already the Newton ring problem – at least for some photos. There were still some showing up newton rings.
So I tried a wet scan: With a normal spray bottle I sprayed some water on the glass surface of the scanner and placed the slide (emulsion side up = not touching the water) on the scanner. I tried to remove all air bubbles under the film, but was quite unsuccessful as I saw on the scan. Next try will be wo put the emulsion side down and use a roller (from linol-cutting) to squeeze out the bubbles. But for that I should buy a clean one first…
My overall impression comparing the dry scan with the wet scan was, that there is only a very slight improvement of the sharpness in the wet scan. If the water is applied to the upper side (base), it had some effect on the color of the image: the scan comes out darker in comparison with the dry scan.
After washing the image, it dried normally having no visible effect on the color nor leaving some marks behind.