weird fogging

[chriscrawfordphoto]

I asked about this before, but I didn't have a scan of it so no one was able to help...it happened again and this time i scanned the film.

http://www.chriscrawfordphoto.com/examples/fog-neg.jpg

I keep getting this weird fogging as seen in the neg scan. It doesn't happen
all the time but when it happens it is only on the first 10-12 frames. The
first few times I saw it it happened on Tmax 3200 film and I thought I had
narrowed it down to one of my OM-4T bodies but this time it happened with
another camera. The last few times I've had it happen were on Efke 100 film.
I don't think its a camera light leak anymore because of it happening on
more than one camera. I don't think its the developing tank leaking
because it is on the frames that are in the center of the reel and I use
metal tanks with metal lids. I think if they leaked light it would affect
the frames near the outside of the reel (end of roll). Also it has happened
with more than one dev. Tank. If it was just the Efke film I might think the
film cartridges leaked light given the lower quality of the carts they
use...but this has happened with several rolls of Kodak film too. The only
other thing I can think of is the changing bag I load the reels in for
developing. I don't have a darkroom so I use the bag...but I do it in a
darkened room and if it were leaking wouldn't it affect all the frames on
the roll? Plus, I developed two rolls in the tank (a 4 reel size
tank...filled the empty places with empty reels) and the other roll was not
affected at all!

What do you guys think? Anyone seen this before? Thanks,


Chris

 

[Photo Engineer]

Chris;

I have seen this happen in either of 2 ways.

1. Bromide drag due to improper agitation in the developer or the wrong dilution of the developer for the film.

2. Pressure fog on the film due to improperly punched sprocket holes. They can be too close, too far apart or slightly off size. This sometimes results from using motion picture film in a still camera or vice versa, or it happens with cheaper off brand respooled film.

I really wouln't hazard a guess beyond this. Kodak film is rarely subject to #2 though due to the exacting cutting process, nor are Ilford or Fuji films.

PE

 

[chriscrawfordphoto]

not bromide drag

I haven't changed my developer or agitation pattern and it's only affecting the first 10-12 frames on the rolls, and often only affects one roll in a multiroll tank. Wouldn't bromide drag affect all rolls and all frames on the rolls?

 

[Photo Engineer]

Chris;

It depends on the tank, how full it is, and the developer as well as agitation. It does not look like fog to me.

I thought this over, and it seems that I saw it happen one time with a camera with dirty sprockets in which the sprockets distorted the film and caused pressure sensitization. That is one of the only other things that came to mind. The other is that old film tends to fog around the sprocket holes first. So, outdated or badly kept film will show fog more strongly in a pattern that can appear like yours.

However, please note that the fog seems to move from low at the bottom of the strip to high at the top. This bothers me. It reminds me of stand development done improperly.

PE

 

[chriscrawfordphoto]

PE,

It was a 4 reel (30oz) metal Nikor tank, all the way full, with PMK developer agitated first 30 seconds and 2 inversions every 15 seconds according to Gordon Hutchings book. I'd have thought it was a PMK problem but the first times I got this was with Tmax 3200 developed in Tmax developer using the same agitation i have used for that film for the last 15 yrs!

 

[Photo Engineer]

Hmmm, could be that the tank is too full???? With a full tank there is essentiallly zero agitation. The tank must be slightly less than full to allow the solution to really 'move'.

Sorry, but those are my thoughts and I just can't come up with more.

PE

 

[gainer]

I doubt you can get the tank absolutely full due to the shape of the lid. I agree with PE that you should not try to get it completely full if the reels are not allowed to move.
You might try loading 3 rools in the 4 reel tank, but not using the empty reel to take up space. The agitation flow pattern with 3 rools and an empty one is not very different from that with 4 full rolls. What volume of flow there is due to the nearly full tank is given a higher velocity near the sprocket holes due to the flow restriction through the holes. (I knew my class in fluid dynamics would have a use some day besides on aircraft wings.) If the reels have more freedom to move up and down during inversion, the fogging mat be so uniform as not to be a problem. This, of course, is contrary to the admonition of some to use "gentle" agitation. I don't recall that Kodak ever recommended gentle agitation.