relating to a former question, can anybody give me some advice about tricks or c hemicals to avoid scratches when developing LF negatives in trays? doesn't it af fect the chemical reactions of developers when adding for example photoflo in pm k?
rgds
herwi prammer
Herwig, You might want to read Adams' "The Negative" which covers tray processing in great detail. Other wise the technique I follow is to: 1) handle the sheets emulsion down. 2) when putting sheets in the first tray (developer or pre-rinse) make sure the on going in hits the liquid flat, so a corner won't dig in. 3) when agitating, lift the pack up with your fingers, separate the bottom sheet and slide it out, placing it on top of the pack 4) use trays at least one size bigger than the film. I've found that the die cut operation that cuts the notches (at least for Kodak) has gottne much sloppier lately and leaves very ragged edges which can be the source of many scratches. I use no chemicals added to any solutions other than photo flow after wash. Film is slippery enough in developer.
Dave
Herwig: Most will disagree, but I can't develop a stack of negatives in a tray, interweaving them and not scratching them. So I develop two at a time, in a tray, with a plastic divider glued to the bottom of the tray. I never get scratches, but it does, of course, take longer. Make sure your nails are trimmed so it isn't you instead of a corner of a sheet of film causing scratches, and make sure there are no burrs on the bottoms of your trays. It is surprisingly hard (takes a good hit) to scratch a negative during development, I didn't realize this until I tried it with the lights on with scrap film. Also, don't mistake small pinholes or large ones for scratches or dings when they may actually be dust in the filmholder. Good luck. Can't begin to answer your question about PYRO, but somebody will jump on it.
I was just wondering why it seems so many people use tray development. I've nev er used it myself; I have always used 4x5 tank development (individual sheets on hangers ). It seems easy enough, and I can't remember ever scratching a negative. I am relati vely new to LF. It seems like so many people use tray development and I was wondering if I have missed something.
The usual advise for tray processing is to develop the films emulsion side down, at least this is what Kodak and Adams's "The Negative" recommend. When I started developing sheet film years ago, that's what I did, and I usually got scratched emulsion. Then I read an article in some photo magazaine that recommended processing with the emulsion side down and have been doing it that way ever since with no emulsion scratches. However, I have found that Ilford and Bergger films tend to scratch slightly on the base side doing it my way. I don't have this problem with Kodak films, and it's not really a problem with the others because I use a cold light head. So I agree with Mr. Walker. Try it his way.
I used to do trays but switched to tanks. If you really want to use trays, make sure to use an over sized tray, 5x7 trays for 4x5 negs. They have to have grooves in the bottoms so you can get underneath each sheet with your fingers. You also have to shuffle them fast enough to keep the developer fresh, between the sheets. The amount of space between each sheet is minimal and that developer will exhaust faster then you think. Also, the volume of chemestry has to be deep enough to keep each sheet properly suspended.
Here's an experiment. Set up a blank smooth card, like a neutral gray card or a mounting board, on the side of your house, in open shade. Set up your 4x5 camera so the card fills the frame, and is out of focus. Make 6 exposures for zones 2 through 7. Then develope them normally in trays. When I did this, the negatives were not evenly developed with the greater density at the center of each sheet. I didn't have to use a densitometer, but eyeballed it on the light box, it was so apparent.
My conclusion, use tanks.
Herwig, I've been tray processing 4x5 sheet film for more than 10 years and have scratched maybe two in that time period. My method is to always pre-wet the sheets in water first, which makes them not stick together. For the developing, I use glass Pyrex bread pans that are slightly narrower than the width of each sheet. This keeps the sheets from settling to the bottom, but the pans are deep enough to keep the sheets submerged in solution. I shuffle emulsion side down, usually no more than five sheets at a time. The narrow, glass pans keep the sheets corralled nicely, so that they don't wander around. Just make sure the sharp corners of each sheet don't dig into the sheet below it, and you'll be fine. If a life-long klutz like me can do this, you can too. P.S. Pyrex bread pans can usually be found in grocery stores or kitchen supply stores.
A presoak for exposed film, before the developer, is an excellent idea. Plain water isn't best, though. Better to use a 1% kodalk solution.The (slippery) alkalinity keeps films from sticking to each other. This idea came from Gordon Hutchings' "The Book of Pyro". It's a great idea no matter what your developer choice is.
I was at a worshop many years ago, and came across this solution for development of LF negs avoiding the possible scratches made by the tray bottom, and the problem of getting one's fingers under the films consistently. Try this: develop in large, stainless mixing bowls. Only the very corners of the film touches the bowl, there's plenty of room to get a hold on the films for agitation, and there is NO chance of bottom scratches. The downside is that it takes a lot of chemistry to do this, but it doesn't matter if you do a replenisher, like D-23,etc. Hope this can solve a problem or two.
I keep reading in this forum that the sheet films are to be developed emulsion side down, as Adams suggests.
I have always remembered reading in " The negative " book (pag 210 edition 1988 ) that the negatives are to be handled emulsion side UP. It makes more sense to me since the softened emulsion can be damaged by the "rails at the bottom of the tray., plus could promote uneven development. although unlikely...
I have used the "emulsion up method for years and with no problems , but i will use a batch with the other method to see if all we are doing is just acting out our anxiety of ruining the only existing link to our finished image....
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