8x10, Photo-Flo, PMK, and Scratches

[David R Munson]

Relatively recently the topic of using photo-flo in the developer to help prevent scratches when developing 8x10 came up. I looked around for more info and wasn't able to find much, so I tried it today and found some interesting results.

First, the specifics. My standard 8x10 developing setup is 2000ml of PMK for developer, water bath presoak and wather bath in leiu of stop bath, and Formulary TF-4 fixer, all in Paterson 8x10 trays. My normal films are HP5+ and Bergger BPF developed for 13 and 11 minutes respectively for normal conditions. I normally develop 4 sheets at a time

For the sake of helping to see results, I used 8x10 Bergger BPF because while it is a lovely film, I have found it very hard to develop without scratching, as the edges seem to be especially rough and/or sharp and seems to be particularly prone to scratching. I have shot about two boxes of BPF in 8x10 and have had at least one irksome scratch on a sheet in each set of developed negs. HP5+ seems to be much less problematic in this regard.

I exposed 8 sheets in conditions of normal contrast range to be developed in two batches. As usual, I mixed up my PMK immediately before starting developing. However, I added about 6 drops of Photo-Flo to the developer while mixing it up for the first batch. I figured I'd up the development time a little to compensate for the Photo-Flo in the developer. The first batch was developed for 12 min instead of the normal 11. Into the dark, into the soup, etc.

During development everything seemed about normal, and after the fix was done I turned on the lights. The first batch looked excellent. No major scratches to be seen, good, even development, and good density (looked normal). I did the second batch with the same amount of Photo-Flo, etc and got nearly identical results. Compared to my usual results, while the amount of scratching wasn't phenomenally better with the small amount of Photo-Flo in the developer, it was definitely better than usual with BPF. My addition of one minute to the development time seemed to be just about right to compensate for the Photo-Flo; the negatives from this experiment had the same density range and contrast of negatives processed for the normal time without the Photo-Flo.

One interesting thing that happened was that the addition of Photo-Flo caused the PMK to darken much more quickly than usual. The working solution looked a little darker than usual when I mixed it up, and when I turned on the light after the first batch, the used developer appeared nearly black. This did not seem to change the effectiveness of the developer, however, in either its development of the negatives or as a bath directly before the wash to encourage image stain.

Not exactly scientific, but I think my little experiment indicates (at least to me) that this technique might hold some merit. I'm going to do some further tests, next time with a little more structure involved, and I'll post the results as I get them. I plan to vary the amount of Photo-Flo to see what amount works best, and then to experiment to see what amount of compensation in development time is needed. If anyone else has tried this or has any input they would like to share, I would like to hear it.

Regards,

[David R Munson]

Point well taken, Dan. Most of the time I use HP5+ in 8x10 and haven't scratched an HP5+ negative in quite a long while now. Bergger just seems to be problematic for me, is all, and I thought I'd see if this would make any difference. There is much to be said for practice and rhythm indeed. Sometimes things just need a little help.

[Bob Ashford]

David, I find it very strange that you feel the need to increase development time roughly 8% when you only add 6 drops to 2 liters of chemistry! Cheers

[Michael Pry]

Dave, I know what you are talking about with the scratching on the Berrger film. The edges on that stuff are wicked. Almost like sandpaper. I love the film but those edges are really bad. I e-mailed the rep John about this and never got a reply. The HP5 has never given me a problem at all. I develop emulsion side down so any scratching I get is on the base side and they really don't print through but I shudder to think if I did them emulsion side up!!!

[Michael Kadillak]

I am not a tray person (yet)- only JOBO, but I was thinking that if the edges of any film are causing a problem, have you considered that small edge rounding device that the photo album companies sell? It could easily be used in the darkroom.

Just place a film corner in the rounder and press. Don't think it would take enough away from the image corner to be a concern relative to a transverse scratch. It would take the corner sharpness away from your film and just maybe make the scratching a little less probable when you tray develop. Just a wild idea.

[David A. Goldfarb]

It sounds to me like you don't have enough room to work in those 8x10" trays, and that may be the source of some abrasions, either with the tank or between the sheets. 2 l. for 4 sheets should be plenty, but try 11x14" trays. This will also let you rotate the sheets 90-degrees periodically as you shuffle to minimize any uneven agitation problems.

[Jim Galli]

Satisfy my curiosity all! I'm also a PMK tray guy (actually ABC+) but the idea of doing "stacks" fills me with fear and trepidation because I refuse to put my skin in this stuff. Therefore I'm limited to doing 1 sheet at a time which is a huge pain in the tush. Fess-up now, do you do all this shuffling with gloves on???!! Or do you have your hands in the Pyro for 12 minutes?

[David A. Goldfarb]

I shuffle one-handed with a vinyl surgical glove. Latex may be okay too, but the box said they could deteriorate with exposure to chemicals, so I went with vinyl.

[David Grandy]

Although I can do only one 8x10 neg at a time, and I don't use PMK; I've found that using a Unicolor drum and roller makes even development a certainty and without any hint of scratches. Slopping around in total darkness with multiple sheets of film in print trays makes me wonder how anyone gets scratch free negs.

[David R Munson]

Jim, I wear latex gloves on both hands while shuffling film in the trays. Considering how they're stianed rather pyro-colored by the end, I really don't think I'd put my hands in the stuff otherwise.