5x4 processing marks. Wetting agent?

[Paul Greeves]

Hi,

I have an issue with processing marks on my Ilford FP4 5x4 sheet film. I appears to be like a greasy deposit on the emulsion side of the film. It does clean off, once the negative has dried, leaving marks to the emulsion. I suspect it has something to do with the wetting agent. I am using Kodak Photo Flo - just a few drops in a litre of water. Am I using too much or too little, or is something else happing to my film? Your expert knowledge would be greatly appreciated. I don't want to waste anymore time/film.

Thanks

Paul

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[otto.f]

Is it just one sheet or more and if so, is it on the same place every sheet?

[Paul Greeves]

It has happened on several sheets and always in the same place. I appears on the upper most corner when drying.

[Tin Can]

are you certain your fingers are NOT a culprit

I wash my hands with Dawn and thoroughly dry them with fresh cotton towel just before touching any film

[John Layton]

You'd mentioned that these artifacts occur in the "upper-most corner" - which implies the same corner from which they are hung to dry. This makes me want to ask what you are using for hanging clips? Wood clothes pins? Metal or plastic clips? Are they clean, dry, and free of residual wetting agent (or any other residues for that matter) prior to each use?

[Paul Greeves]

Thanks John. I use Paterson film clips. There is only the point of the pin touching the film.

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[Ken Lee]

Tray development ? Tank development ?

You might find it helpful to clean your hands and fingers with Isopropyl Alcohol whenever handling your sheet film. That means before taking it out of the box, before loading the film holders, before removing it from the film holders, before development, etc. Be sure to clean your trays or tank with a solvent to remove any grease as well.

When unloading sheets before development, do you place them in a box or set them somewhere briefly, or do you place them right into the first tray - like a water bath ? If you set them down somewhere temporarily, be sure to determine if that place is free of a grease spot too.

Have you inspected an unexposed and undeveloped sheet, right out of the box ? This will remove almost all the variables. If every sheet is contaminated this way, you may have a "defective" box of film. Perhaps the person who initially packed it, forgot to wear gloves or clean their hands properly.

Have you tried developing an unexposed sheet ? Without Photo-Flo ? This will remove several other variables, including any grease or dirt inside the film holders and additional handling. If it's easier to see the greasy deposit on a more densely exposed area, then leave the lights on while you process the film. You'll find out how often you touch the corners.

[Paul Greeves]

Thanks Ken. I use a Combi Plan tank. I loaded the sheets from a combination of sheets stored in an old film box and from the dark slides. There were marks on both. I think there were more marks on film that had a few drops less wetting agents. I will take your advise and degrease my hands before touching the film. I use other formats like roll film and 35mm, where I haven't had the same issues. I might try heating the drying area before hanging up the film to speed up the drying. Also, I could try to remove most of the water before hanging up the film.

[Tobias Key]

Thanks Ken. I use a Combi Plan tank. I loaded the sheets from a combination of sheets stored in an old film box and from the dark slides. There were marks on both. I think there were more marks on film that had a few drops less wetting agents. I will take your advise and degrease my hands before touching the film. I use other formats like roll film and 35mm, where I haven't had the same issues. I might try heating the drying area before hanging up the film to speed up the drying. Also, I could try to remove most of the water before hanging up the film.

I use a combi plan tank and have found I get the occasional mark on the film if I don't make sure the emulsion side of the film is facing away from the middle of the tank. Also make sure you thoroughly clean the tank after use by unscrewing the valves and rinsing them out, they can hold wetting agent from the previous dev session which can land on your film before development starts leaving a patch or mark. Other thing to check for is that possibly two sheets touched during development. I always give the sheets a little pull with my finger tip to check they are secure.

[Doremus Scudder]

... Also, I could try to remove most of the water before hanging up the film.

There's your problem. And I concur with your diagnosis in the first post: wetting agent residue.

I know a lot of people say to not touch the film after the final bath in wetting agent, but (and especially, if you're not mixing your Photo Flo carefully, which you aren't) leaving lots of water on the film to just run off and dry leaves lots of residual wetting agent on the film after the water has evaporated if it hasn't dripped off like it is supposed to. So...

1. Mix your Photo Flo as per Kodak's directions (1:200) or weaker. You can use a weaker than recommended solution if, and only if, the surface tension of the water is definitely broken, i.e., the water sheets up on the surface of the film leaving no drops or discrete puddles.

2. Make sure your final bath of wetting agent is freshly mixed (Photo Flo working solution does not keep well) and mixed in distilled water (this latter especially if you have less-than-perfect tap water). I keep a jug or two of distilled water around just for this purpose.

3. Soak your film, with gentle agitation, in the wetting agent solution for at least 30 seconds. Longer won't hurt and is recommended if you have lots of dissolved minerals in your tap water. I do, and soak for three minutes or more.

4. Lift a sheet from the wetting agent and squeegee it gently between index and middle finger vertically along one side. Flip the sheet along the vertical axis and repeat for the other side. Make sure your fingers are clean, smooth and have been dipped in the wetting agent first. This removes most of the standing water on the film. The rest should be fine as long as you...

5. Hang the film to dry by a corner, so that there is a bottom corner functioning as a collecting point for the remaining water to drip from. After a few minutes, remove the collected water that is no longer actively dripping from the bottom corner of the film by touching the tip with a finger or a paper towel. You don't want to wipe, just coax the water to run off to your finger or into the paper towel.

6. Leave everything alone till the film is completely dry.

Hope this helps.

Doremus

[Paul Greeves]

Thanks. They were in different holders.

[Paul Greeves]

Thanks Doremus.

I think you may have spotted the problem/mistake, on my part.

After the final wash, I was just adding a couple of drops of Photo Flo to the water in the Combi Plan tank, lifting the film carriage a couple of times to agitate, then hanging up without squeegeeing off the excess water.

As you correctly point out, this wasn't mixing the Photo Flo properly in the final wash. I will follow all your guidance above and we shouldn't have any more issues, finger crossed!

Cheers

Paul

[Willie]

After a bit of time using your fingers to squeegee the water off you will be asking us "what makes these streaks and marks on my film"?

If you have mixed the distilled water & photo flo right the water will drain off without your having to risk damage due to pressure from wiping it.

[David Schaller]

I would also suggest doing the photoflo step in a separate tray, rather than in the tank. I do that, one sheet at a time, while the other sheets remain in the tank in the wash water.

[Paul Greeves]

Thanks David. That sounds like a good idea. That should allow the wetting agent to reach the film evenly.

[Doremus Scudder]

After a bit of time using your fingers to squeegee the water off you will be asking us "what makes these streaks and marks on my film"?

If you have mixed the distilled water & photo flo right the water will drain off without your having to risk damage due to pressure from wiping it.

I've been squeegeeing my sheet film using my index and middle finger for 30+ years and have never had streaks and marks. Being gentle is the key, along with mixing the wetting agent correctly. Of course, it won't work with rough, calloused fingers; that could scratch the emulsion.

However, just skimming the film gently with very little pressure to remove excess water won't leave a streak unless your wetting agent is not diluted enough.

But, I don't want to start a "to squeegee, or not to squeegee" discussion here; the object is to help the OP.

Certainly, if conditions are optimal, squeegeeing is not needed; the water will just sheet right off the film. So, let's recommend to the OP that if squeegeeing leaves streaks and marks on his film, he should definitely try without squeegeeing, but adjust the wetting agent dilution till it leaves no residue.

Best,

Doremus

[David Schaller]

Thanks David. That sounds like a good idea. That should allow the wetting agent to reach the film evenly.
It also keeps the photoflo out of your tank!