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Sheet film strange uneven density

Jordan.K

Member
Allowing Ads
Joined
Oct 16, 2006
Messages
261
Format
4x5 Format
My film is drying in a way that leaves almost a border in an "L" shape along one long and one short side. It is an "L" shaped area of less density on the negative that only shows up on occasion. It is located always on the notch code edge and side closest to the notch code. I hang my film from the notch code corner. I use a jobo 3010 expert drum to process my film with the notch code oriented at the upper left. HC110, 8 minutes, speed setting is 4. I put my film in the holder with the notch code in the lower left, thus rise and bellows sag are ruled out I feel. Could film drying unevenly leave an area I have described? Thank you all in advance for any answers.
 
It would be nice to have an image scan to check, picture worth a thousand words?
 
Is pattern consistent or varies? Different films and holders? Since you do some architectural photography, any extreme tilt, shift, swing, rise?
Btw, nice work on your site.
 
I've seen that on very old film occasionally. Seems to be from humidity seeping in and desensitising the emulsion.
Otherwise I'd say it's a development effect of some kind.
 
I bet for chemical degradation of the film. Developing effects tend to increase the negative density near the edges, because we have in this region better transport condition for fresh developer and for removing bromide as well. This would lead to lighter areas in the positive at the edges. But we see the opposite.
For a fast try I recommend to take an image using photopaper, wich should be fresh, or you take the inner part of a large sheet at leasts. If you don't have the effect on the paper the old film is the reason.
 
I had this happen once from partial drying, re-wetting, then re-drying. The film was hanging up from the wash, I noticed some dust while the film was partly dried. I took it down, re-wet and removed the dust, then PhotoFlo again, and re-hung the sheet (4x5). It left the same effect. I know you didn't do this, but there may be a clue here relating to uneven drying.
 
Well, it doesn't make sense, I agree, but the area of different density (even the quality of the transition) matches the look of the neg when I took it down to rewash.
Maybe Photo-engineer can comment?
 
Looks like the most dangerous evil to film users

Insufficient agitation in the first 15 seconds , creating uneven development.
 
If it is somewhat regularly happening, then I suggest you try turning your film 180 degrees for a few sessions. See if it is positionally related to the way you agitate/load/who-knows-what. If it follows the film substrate, suspect some kind of damage to the film. If it stays in the same position relative to the tank, look there.

If it happens irregularly, you may have a tough time investigating.
 
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