8x10, Photo-Flo, PMK, and Scratches

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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.


-- David Munson (apollo@luxfragilis.com), May 27, 2002


If scratches are a problem take a good look at your technique rather than adding photo flo. Practice in the light with a few sheets of film, lifting and placing the film flat on the chemistry & tapping under with a finger to keep scratching to a minimum. Processed 30 8x10's in batches of 6 each over the past two days & not a scratch anywhere. I find when I get in a hurry I find a scratch or two so relaxing in the darkroom & working smoothly is the way that works for me. I will put off developing if I am pushed for time or something else seems to be occupying my mind at the time. Giving full concentration while developing, working smoothly & getting into a 'flow' as I interleave the negatives makes a world of difference. I keep them corraled with one hand so they don't drift all over the tray, making sure I use a tray larger than the size film I am processing, and lift the sheets evenly and make sure I put them back into the chemistry flat... no sharp edges first even if I have to hold an edge to make sure it doesn't go into the chemistry first. It takes a bit of practice just as does fine dancing but when you get into a rhythm both work much more smoothly.

-- Dan Smith (shooter@brigham.net), May 27, 2002.

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.

-- David Munson (apollo@luxfragilis.com), May 27, 2002.

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

-- Bob Ashford (ashford@kfshrc.edu.sa), May 28, 2002.

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 Pry (vila@busynet.net), May 28, 2002.

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.

-- Michael Kadillak (m.kadillak@attbi.com), May 28, 2002.

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.

-- David Goldfarb (dgoldfarb@barnard.edu), May 28, 2002.

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?

-- Jim Galli (jimgalli@lnett.com), May 28, 2002.

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 Goldfarb (dgoldfarb@barnard.edu), May 28, 2002.

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 Grandy (dgrandy@grandyphoto.com), May 28, 2002.

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.

-- David Munson (apollo@luxfragilis.com), May 28, 2002.

Interesting discussion, which I would like to add a few comments and questions to. First, in defense of David's technique, I have also found that BPF scratches more easily than most other films during shuffling in the trays. Not only are the edges of the film rougher, but it seems to me that the emulsion is a bit softer as well when compared to T-Max, Tri-X or the Ilford films. Even the most skilled workers occasionally scratch a neg, and anything that will reduce that incidence would be helpful.

Also, I tray develop with PMK wearing vinyl gloves on both hands as mentioned above. Although a bit more fiddley than bare hands, it is remarkable how much sensation is retained and how easy it is to feel what you are doing. When developing large amounts of film, I simply leave the gloves on for the whole session, washing them like I would my hands and unloading the filmholders with them on as well.

Now on to my questions: I am curious as to the need for increasing development time when adding Photo-Flo to the developer. I would think that the surfactant would make it easier for the developer to break through the tension barrier and, therefore, increase it's activity somewhat. This would result in a shorter development time to reach the same density. Could someone clear this up for me if I am mistaken.

I am also curious as to why the Photo-Flo would cause the PMK to oxidize more rapidly than usual and turn so dark so quickly. Perhaps one of the photo chemists in the group could enlighten us. Possibly another type of surfactant would not have this effect.

Last, and most significantly, why would a surfactant, which breaks down the surface tension of liquids at a molecular level help to prevent scratches when developing. I would think that it would remove even the small cushioning and lubricating effect of the surface tension and make scratching negs easier. Could you explain your thinking on this to me? It seems I am missing something.

Thanks, ;^D)

-- Doremus Scudder (ScudderLandreth@compuserve.com), May 28, 2002.

I don't know much about the chemistry of it all, so I can't explain why it causes the PMK to oxidise more quickly, etc. I originally came across the idea 3+ weeks ago in a thread regarding how Jock Sturges develops so much film at a time. Somebody said he used Photo-Flo in the developer to help prevent scratches, which is where I got the idea. How/why it does (or doesn't, for that matter) make a difference I do not know, but plan to test some more to find out.

-- David Munson (apollo@luxfragilis.com), May 28, 2002.

Jock Sturges does use Photo-Flo in the developer to help prevent scratches, and he uses a lot more then 6 drops.... He also works with 18 sheets at a time.

-- Jay Lynch (jay_lynch@yahoo.com), May 29, 2002.

OK - I have to ask... (sorry I've been thinking) when everyone is talking "scratches" are you talking "damaged emulsion" to the point of being a problem when printing? Or are these things you see and worry about but really have no effect on the final product. I have had a few(out of thousands) where I damaged the emulsion and I KNOW WHY in all cases. But if you are talking about the "VISABLE" burnish marks on the Base side, is this really an issue? As has been pionted out, the grease works great. But in thinking about this issue I just opened up a box of unused (Expired and not stored proper) 4x5 color that I have had laying around. Allmost every third sheet has some "VISABLE" marks on the base side from just the manufacturing and packaging or a least that's what I'm guessing..... Any thoughts?

-- R.L. (Mac) McDonald (rmacsteam@aol.com), May 30, 2002.

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