film fogging

Steelbar said:

Noel- ...
I just thought of another way to look for a light leak. If I set my camera up with a wide angle lens in my darkroom and leave it exposing for a very long time I may find there is a leak. I really can't see there is a light leak with my naked eye.

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Steelbar,

Try placing a mirror in the position of your film, then search the mirror at all angles for your light leak.

As to your problem. I really think it has to be light from somewhere, not chemistry. If you want to be sure, do the same test, in the same air, but place your film under a lightproof box. I'll bet there won't be any fogging. Light leaks that the film can see but you can't are sometimes hard to trace. Keep looking, you'll find it.

Doremus

Doremus Scudder said:

Steelbar,

Try placing a mirror in the position of your film, then search the mirror at all angles for your light leak.

As to your problem. I really think it has to be light from somewhere, not chemistry. If you want to be sure, do the same test, in the same air, but place your film under a lightproof box. I'll bet there won't be any fogging. Light leaks that the film can see but you can't are sometimes hard to trace. Keep looking, you'll find it.

Doremus

Click to expand...

I like this image.

You can stand in your darkened darkroom, focusing on an upside-down, empty box, for about half an hour or so.

Call me if you need help explaining this to your family:devil:.

On a more serious note, I think you should try the same experiment with roll film, and then develop that in a tank.

If there is no fogging on the roll film, the problem might be localized to where you are tray developing your sheet film.

Doremus
I know chemical fogging does not sound reasonable but this room is now darker than any darkroom I have worked in. The last test I did was at night with almost all the lights out in the house and the door blocked with a blanket. I will try putting a box over the film next time.


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OK what chemicals have you got in the room that are not enclosed in air tight containers? If there are no open trays or open chemicals then surely most of us will suffer your fate? Certainly I cannot believe it is ordinary paper developer, stop or fix. I have a Nova Quad that contains these chemicals and essentially these are always open to an extent to the air in the darkroom. Never noticed any problem

I'd open windows and/or door for a few hours, remove or at least ensure that all chemicals are tightly stoppered and try the test again.

pentaxuser

Well I got a fog less negative by covering the door,doing it at night, moving to another counter and covering the film with a box. That would confirm that it is not chemical, now I need to figure out were the light is leaking in. Thanks for all the suggestions.



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Its insidious! Damn light seems to go around corners! I'm having the same issues here……thats it! Im digging an underground bunker! To hell with the landlord!

You guys know where I can rent a jackhammer?

Just keep in mind, for paper, fog is damning. For film, not so much.

For film, if it's not "measurable", like if I get Base+Fog under 0.08... I don't consider it worth hunting down light leaks to bring it down farther. From a negative, you always can print through fog. And you're talking about a small difference in the darkest shadow on the print.

If it's extreme, like measurably 0.04 density due to fog or more, then of course try to get it down.

But worst case, 4x5 sheet film usually only spends 15 minutes in developer tray... So if it takes that long to fog, it's going to be in the stop and fix soon enough.

I don't mean to claim fog is good. It's generally considered bad. But 0.01 or 0.02 isn't going to ruin a negative like it would ruin a print.