4X5 TMax 400/TMax RC & Brown Stains

[rcjtapio]

Hello all....

I would be interested in communicating with anybody using the combination of the new & improved 4X5 TMax 400 & TMax RC developer. I process my film in a Jobo tank & have noticed a light brown stain in the clear part of the film after development. It is on the emulsion side of the sheet & can be scratched off with my fingernail when dry. I have no idea where the stain is coming from & would like to tap into the collective genius of this group.

I called Kodak & talked with the B&W rep there & they have had no other reports of this happening. I have been processing film for over 30 years & have never seen this. Also, this has only happened since I switched to the new & improved TMax 400. (It is not the same problem where a mageta color shows up from insuffient fixing. I still get the light brown stain using fresh Rapid Fix.)

I use a acetic acid stop with the indicator. Could that be a problem?

Has anybody else experienced anything similiar using this combination? Any ideas might be helpful. Thank you in advance.

Rick Tapio

[Louie Powell]

I would suspect one of two things -

Incomplete fixing can result in brown stains. Normally, those stains won't scratch off without damaging the emulsion.

A more likely possibility is a problem with washing. Are you using a PhotoFlo final rinse? And if so, are you mixing it at the recommended strength? And in what kind of water? Have you had your water tested to determine its natural iron content?

PhotoFlo can leave a residue on film, especially when used at the recommended dilution. It's a good idea to always dilute it more than the manufacturer recommends - perhaps by as much as twice the recommended dilution. Keep in mind that the purpose of PhotoFlo is to relax the surface tension of the water so that it will dry without leaving spots, so diluting it more doesn't really hurt.

Second, if you use ordinary tap water to dilute PhotoFlo, and if your water has a high mineral content, you can still leave a mineral scum on the film. I've always used either distilled water (actually, water that I captured in a dehumidifier and then filtered) or water that had been processed through a reverse-osmosis filter to make the final rinse.

[rcjtapio]

Thanks for your comments, Louie. I suspect the stain is happening during the developing process because I see the stain before the photoflo step. (I use the photoflo in a tray after the wash as I believe photoflo is not good for Jobo tanks)

I mix the developer right out of the bottle. I do not make up a working solution. Could it be that the developer is going bad in the bottle? Also, I do a 5 minute pre-wash in plain water before the developer. I have no idea what is in my water. Maybe using some distilled water in one of the next batches would be in order.

I think the next batch I develop I will go back to plain water as the stopbath. Maybe the indicator in the acetic acid is staining something?

I did try refixing a negative & the stain did not clear....si I am thinking it is not a fixer problem, but something before that step in the processing.

Again, thank you for responding.

Rick Tapio

[nolindan]

4X5 TMax 400 & TMax RC developer. I process my film in a Jobo tank & have noticed a light brown stain in the clear part of the film after development. It is on the emulsion side of the sheet & can be scratched off with my fingernail when dry.

I have had this happen - dichroic fog. By reflected light it should have a slightly greenish sheen on the emulsion side.

Some developer and film combinations are prone to it. T-Max developer will cause it with TMax sheet film - both per Kodak's warning and personal experience. TMax RS is supposed to be OK with this regard. Microdol (hombrewed without the 'X') will cause it on Ilford non-delta films.

The problem is also caused and exacerbated by not using an acid stop bath and/or using developer at close to capacity.

[nolindan]

I use a acetic acid stop with the indicator. Could that be a problem?

I have had paper get an orange tint to it from Kodak Indicator stop bath, mixed per instructions. I now make up stop bath from 28% AA (made from glacial AA), and add a drop of indicator stop just for a light yellow tinge of indicator.

I would try D-76 as a developer next time and see if the problem goes away.

I have used TMax RS in a Jobo, diluted down from the bottle of stock just before use as you do, with the old TMY 4x5 with no fog.

[rcjtapio]

Hi Nicholas....

Thanks for responding. If it is dichoic fog, is that something that will scratch off of a dry negative? I know when I presoak the film in water, after 5 minutes it turns the water purple which is is dichoic layer washing away.

I have had no problems like this with the old TMax or TriX & HC110. I have only seen the stain after using the NEW & IMPROVED TMAX. I am suspecting the yellow stop bath. I think the next batch I will stop with just plain water & see what happens.

BTW...did you get any good images from Spring Mill State Park? That was a fun weekend & I enjoyed camping under the stars. Hope to see you on another asylum outing. Maybe we should plan on an outing near Cleveland.

Rick Tapio

[Jim Edmond]

John Sexton mentioned something similar in this article:

http://www.largeformatphotography.in...xton-tmax.html

[nolindan]

... I am suspecting the yellow stop bath. I think the next batch I will stop with just plain water & see what happens.

If it is dichroic fog it won't wash off with water. Any color in the wash water is probably some remnant of good-ole-tmax-purple.

Dichroic fog is silver that has been redeposited on the surface of the emulsion as a thin layer of metal. Like a dichroic filter it takes on a colored appearance dependent on the thickness of the metal layer. It should reflect a complimentary color. Many dichroic filters for photography are combination of a gelatin filter and a metal dichroic filter and don't exhibit this behavior.

Eliminating the stop bath will (or should) make the problem _worse_.

It can happen if developer laden film is placed in used fixer - the developer in the gelatin will develop the silver in the fixer, where it sticks to the surface of the gelatine. Stop bath deactivates the developer so this won't happen - it is important to let the film sit in the stop for the full minute or so.

It has also been noted with some high-sulfite developers that have a large amount of dissolved silver in the developer. The here-to-dissolved silver in the developer is deposited as developed metallic silver on the surface of the film.

As the Sexton article referenced above suggests: try a few seconds (30 may be too much) in Farmer's reducer. If you have a 'throw-away' negative then immerse half the negative in the reducer for 15 seconds, rinse and compare to see if this makes the fog go away.

Richard Knoppow on usenet's rec.photo.darkroom has more information on dichroic fog.

an outing near Cleveland.

There is a Cleveland area APUG outing on the weekend of the 20th. The same time that the Midwest Asylum is planning the Upper Peninsula trip.