Reversal processing, user's tips

To all interested:
Here are a few tips from my practice of enlarging negatives by reversal
method ( I use APH or APHS film from Freestyle):
1. Exposure. I use a light meter to set the enlarger. I set the aperture
of the enlarger lens without film to EV reading of 2.3. This way I am
consistent with exposure for different film/ negative sizes. This is also
important for my flash exposure. 10-40 seconds is a good guess for initial
exposure.
2. Flash exposure (with no negative). I already have a light set in step
1. I slip an 8xND filer in front of the lens and expose for 10 to 15
seconds. I would use 10 to 12 seconds for a palladium printing and closer
to 15 seconds for a gum over palladium as I like to have somewhat less
dense shadows.
 You could step down the lens to have the same effect, but I have found
that this is most of the time not possible.
3. Developer: Dektol 1:2 for 4 minutes
4. Chromate bleach. My experience is that the sulfuric acid depletes in
the batch before the dichromate, so I add 50% more sulfuric acid. No big
deal, but I can get more mileage from it.
5. Wash after the chromate batch. I use two trays of distilled water. I
let it soak in the first tray for 5 minutes and then second tray for 5
minutes. I would change the water maybe every 5-10 negatives.
6. Wipe the negative clean. This is very important in my practice.
Chromate bleach leaves a residue of silver sulfate on the surface of the
film. If not completely removed it will result in an incresed density and
spots from handling. Easiest way to remove it is to place the film on a
rigid surface (glass) under running water and wipe the surface clean. I
use my hand. The film is hardened at this point and does not scratch
easily. I either wash it or use sulfite bath at this point.
The rest of the processing is as described in the literature.
Happy printing.

Marek, Houston
Received on Fri Mar 12 12:32:53 2004