Weird residue on film _HELP!

[orlovphoto]

I see this every once in a blue moon and today was pretty bad so I decided to ask and see what you folks might think. I develop on average 20 rolls of film a week and maybe once in a few months I'll have what looks like fine brown residue on the emulsion side of the film. It comes off (very reluctantly) after some rubbing with Kimwipes while the film is still wet, but why the heck is it there??? I developed about 20 4x5 sheets today and all of them have it - then I used THE SAME exact chemistry (I mean SAME not fresh even) and the 6 rolls of 120 are perfectly clean and clear... Mind you I had the brown stuff show up on two different types of film... Any real help would be great...

 

[Helen B]

Is there any possibility that you have occasional minor problems with rust/ochre in the wash water? Do you run the wash water through a filter?

Otherwise could you tell us more about your chemistry and type of tank etc.

Good luck,
Helen

 

[orlovphoto]

Hi Helen,

I'll rule out water, since I've been developing at this place for a few month and did probably over a hundred rolls by now, but rust is exactly what it does look like. BTW I tried cleaning it off after re-soaking a negative and no luck, that stuff is cooked on there now... it came off relatively easy when it was still wet yesterday.

Yesterday the 4x5s were Tmax 100 and Ektapan and 120s were Delta 100, all in T-max developer. It's probably the tank though since I re-used that chemistry on two 120 rolls and they were perfect - it's an old Nikor adjustable sheet film tank that takes up to 12 sheets of whatever you got up to 4x5. It is rather old indeed and probably has a nice layer of rust hiding inside that super-complicated lid... I always use steel tanks, but have plastic lids on all the other ones except this one since they let chemistry in and out way faster and you don't have to fight to get the darn thing off when you need to and it's wet and slippery.
In short - what could I possibly soak that lid in that would take off the rust?

And would you ever attribute a problem like this to something other than rust or water (such as the age of film or chemistry)? Because very very seldom I see slight 'dirt' on my Kimwipes when I wipe the roll after hanging it... Happens very rarely and to a much lesser degree than this time, that's why I ask if there could have been anything else... all my other tanks are definitely rust-free.

Thanks a lot.

 

[orlovphoto]

and yes.... a filter would be a good idea when I get a little more revenue from this place...

 

[Images]

If the problem were rust from the tank the film was developed in I would think the chemistry would be so contaminated that it would be useless, at least it would transfer to all the film that was developed in those chemicals.
How are you washing the stained film, is the wash different for the roll film.
Some developers can get rather skanky as they oxidize but I have never seen them produce a residue that couldn't be washed off, plus it would be on all film.

 

[orlovphoto]

same washing procedure - in a Gravity Works tank.... I know, this is a total mystery for me right now... Oh well, I might soak the tank in some de-corrosive and see what happens there...