Negative headache

[marcel_perez_calisto]

Hello:

I am experincing a very unusual (?) problem in my 4x5 negatives: the

out of focus sections have irregular areas (small) of lighter density

(almost clear). It looks like dust or lint during loading, but I am

99% sure it is not that. For one, this areas are not clearly defined

or sharp as with dust/lint etc., and also they are exclusive to out

out focus areas and vary in density. Here is my system: vaccum film

holders and load film in bathroom after running hot water for a

while. Develop in pyro PMK using Jobo drum and motorized base (fix

and wash normal). I use delta 100 at asa 50 or fp4 at 64 with

reversed rodenstock apo 50mm enlarger lens with 400 to 700mm bellows

extension. Could this be lens related? I read the portion of the book

of pyro that deals with problems in the negative but could not find

an answer.

Thank's in advace for the valuable feedback!

 

marcel

[michael_kadillak6]

Is the clear area defined on your negatives in any way a circular event? If so, you are running into a lens coverage area in that you are beyond your lens ability to produce a visual image on the negative. That is where I would put my money.

 

I am not familiar with a reversed enlarger lens as you mentioned, but look carefully at the edges of your ground glass and would suggest using a point light source to fully evaluate this event. I like the small Mag Light with the end unscrewed and placed carefully in the scene. In addition to a quality focus (diffused light that becomes sharp at critical focus) it also can be used to evaluate coverage.

 

Good Luck

[marcel_perez_calisto]

Michael:

Thank you for your feedback. I forgot to mention that this problem occurs in various areas of the negative, not the edges. I am sure that I have enough coverage, at least visually through the cut corners of the ground glass, also there is no obvious sign of vignetting. Is that the kind of coverage you were refering to (size of image circle) or something to do with aberrations at the edge of the coverage?

Thanks again...

[brian_ellis3]

You're using a 2 inch reversed enlarger lens (i.e. a very short process lens) for a purpose for which it isn't designed, and using it with 16 to 28 inches of bellows extension (i.e. the approximate eqivalent of using a 150 mm "normal" lens with 1240 mm to 2100 mm of bellows extension, which is considerably more bellows extension than any 4x5 camera actually has). I have no idea of the scientific explanation but I'd be willing to bet that your problem is related somehow to the use of that lens in that manner. Is this the first time you've used the lens? If not, is this the first time you've had this problem? Do you have a "normal" lens you could try to see if the same thing happens with it?

[gary_meader]

Marcel

This may be a simpleton's answer, but the phenomenon you

describe sounds like simple air bells. Your processing sounds

OK, but that's my guess.

Gary

[james___]

Water droplets forming on the film when loaded.

[brian_ellis3]

He says the areas aren't clearly defined or sharp and are limited to the out of focus areas in the negative. This doesn't sound like air bells to me. Air bells are sharp around the edges and appear randomly throughout the negative, not just in the out of focus areas.

[marcel_perez_calisto]

Thanks everyone for the feedback. After going over every step and assuming it is not a lens defect (I have heard of many people doing exactly the same thing without problems, and the focused part of the image is GORGEOUS!) I came up with a theory. Could it be developer splashing the film as I pour the pyro in the tank? I use a Jobo 2551and 1500cc's of chemistry so it takes a while to pour (I pre-soak the film for 1 min.). I also thought about sudsing and maybe using Edwal LFN. Any thoughts? Again, thanks in advance.

 

P.S. I forgot to mention that I got the same faults using a macro digitar 80. So is it just a problem of coverage or am I missing something about lens design and engeneering? In other words, if I get enough coverage, shouldn't the whole image fall within certain parameters?... (I understand about loss of definition at the edges)

[steve_feldman2]

M.

 

I'm with the guys that are saying it's air bells. I used to have a BIG problem with those nasting little bells - but no more. Here's my remedy: Pre-soak with one drop of photo-flow (or eq.) in the water. Add one drop to the developer also. Bingo! No more air bells.

 

Give it a try. Let us all know if it works for you.

[brian_ellis3]

If the developer always splashes only on the out of focus areas, or if the air bells form only on the out of focus areas, then it could be either. In my experience air bells form, and water splashes, randomly. They don't possess the knowledge to form only on the out of focus areas.

 

OTOH, strange things happen in photography. Only your best photographs are ever ruined by scratches. Dust spots appear only in large areas of uniform density such as the sky. And of course the photographs you miss as the light changes would always have been the best photographs you ever made. So who knows, maybe your air bells and developer are so highly educated that they limit themselves to the out of focus areas for some perverse reason that only they know, but that would be odd to say the least.