Thumb prints

[Guy Boily]

First for me. I have been shooting large format (4X5) for about 12 years. When Kodak discontinued their infrared sheet film I transferred over to Maco 820c. So far so good. My last batch has been driving me crazy. When I say driving, I mean driving. I have visited a site 80 miles from my home twice. The 1st time I had thumb prints on the negatives on the notch side. So I went back today and shot two more sheets. I am always carefull when loading or unloading film. This time I used gloves just in case. I just developed them and guess what, thumb prints. Some of them seem to have been left from a humid thumb. Never had this problem before. I would have to compare my thumb print to positively rule this out though. Has anyone experienced a similar situation? Maybe CSI Miami can help. www.guyboily.com

[Ralph Barker]

No, can't say that I have, Guy. Your problem with enlisting the help of CSI Miami, though, is the blonde handles mostly ballistics. ;-)

Could the thumbprints be introduced during processing? Or, do you wear gloves (or use a tank) then, too?

[Philippe Gauthier]

Ralph: Thumbs prints introduced during the processing? I've always been taught that thumb prints during film loading didn't matter much because they always dissolve during theprocessing stage - and my experience reflects this.

Guy: I have no clue. It looks more like factory damage or something... Is all ypur Maco IR film from the same box or the same batch?

[Guy Boily]

All the film is from a new box and they all have thumb prints so far. The 1st 6 sheets have finger prints. I checked and the date (2004-5) & emulsion # 110574 are identical. All the sheets are handled by the edges and all are developped in Kodak tanks. Guy

[Jorge Gasteazoro]

Guy, let me put it this way, it is impossible to load a 12x20 holder, or unload it for that matter, without putting a thumbprint somewhere. Yet, after development I have not seen a thumbprint at all in any of my negatives. It must be a production flaw.

BTW, I would not go with the blond at Miami CSI, just hearing that voice would drive me to confess to any crime just to shut her up...:-)

[wfwhitaker]

Hate to ask the obvious, but are they your fingerprints? That would at least suggest your level of complicity.

[domenico Foschi]

Couldn't you wash them, instead of driving 80 miles and shoot the same scene?

[Roger Scott]

I just checked the last couple of sheets of Maco 820c I processed and they're fine (different batch to you). I usually end up putting my finger and thumb on the edge of the sheet to get it out of the holder so if there was going to be a print from me it would have shown up. I doubt the print is from you unless you dipped your hand in fixer before loading or something :-) - more likely a factory problem. Unfortunately the last roll of Maco 820c 120 I processed had the emulsion come off in spots - almost like a rasp had been dabbed on it so I'm leaning towards suspecting some sort of manufacturing problem with that as well.

[John D Gerndt]

If I may ride on this thread: I know I put a thumbprint on a sheet of J&C 200 but what mystifies me is the effect! It caused a white flare (like my thumb was on fire) across the negative and that sheet, processed along with several others in (Pyrocat HD, BTZS tubes) had a higher CI and a different (straighter) density curve. Does anyone know what happened?

[Tim Curry]

I managed to get a print on one sheet of film, a very nice image. I had opened the fixer jug just before handling the film, and must have had some residue from fixer on my finger when I unloaded film the film holder. That's the only thing I can see which would have affected the film as it did in this case.

[Guy Boily]

Thank you all for your priceless feedback. I contacted the dealer in Montreal, L.L.Lozeau, and they suggested that I run a test. I took the 1st, center and the last undeveloped sheet. Next I took the center of each sheet with my thumb and index finger, pressed hard and loaded my holders. I then exposed each sheet as usual with an IR filter plus a white opaque plexiglass to get an even Zone V. All were developed as usual. When dried I inspected them with my loupe. My prints in the center do not show at all but there are other prints on the edges and sometimes in other areas. So the case is closed, or almost, I am innocent. I rest my case. The person who loaded the box probably had wet hands, it was very hot or had chemicals on his or her hands. If you ever have this problem, as rare as it may be, you will know what to do. Thanks again. www.guyboily.com