Rodinal base fog

[colin_lee3]

I know there was a recent post on a Rodinal and the appearance of a

base fog when using 400TX, but I have the same problem, and I think

I have it isolated to the Rodinal, but I still can't understand why?

 

I developed my 400TX in Rodinal 1:25 and got a base fog, but

initially assumed it wasn't adequately fixed. Re-fixing didn't

help, so I was stumped.

 

My next roll of 400TX was split onto two different reels, and

developed with two different bottles of Rodinal (my friend had a

bottle from about 10 years ago kicking around). I was shocked when

my bottle of Rodinal gave the same base fog, but the ancient bottle

yielded negatives which were perfectly fine.

 

I had purchased the Rodinal back in December. I looked back through

my negatives, and found some 400TX developed in Rodinal from 3

months prior, and they look fine.

 

Any idea what could have happened to my Rodinal in 3 months?

 

 

Colin

[silent1]

I'd guess there's been a change in the water you're using to dilute the Rodinal that, for some reason, is having less effect on your friend's well "seasoned" bottle than on your relatively fresh one. The only simple way to test would be to buy a brand new bottle and compare against what you already have and what your friend has had for the past decade.

 

Seasonal changes in water are common in many locations -- I grew up in a town where the water in summer would turn yellow, or even brown, from dissolved iron (because they had to start pumping the less desirable wells when demand rose). Developing with that tap water was Not Recommended...

 

Simple solution is to use distilled water for your dilution (and you might use it for the final wash, too, if you don't already). Its composition doesn't change over time.

[jrileystewart]

I recently compared fog on 4x5 TMY (TMAX 400) developed in 20 year-old Rodinal and new Rodinal. I didn't see any difference in fog. Both gave me .1 density units, which may seem high to you. It's pretty normal for me with TMY, regardless of my developer. The age of the Rodinal may have nothing to do with your problem.

Jim

[lex_jenkins]

Yup, I'd first look for other possible causes, such as the water. I always use distilled water now because our well water source has become unpredictable - it's in a limestone basin and all the local wells have been affected by recent oil well drilling in the area.

 

I've tried Rodinal with and without borax for stand processing to evaluate the effect on base fog. Two hours of development should reveal base fog differences but I saw none.

 

Is this all the same batch of Tri-X, either factory rolls from the same lot number or roll-yer-owns from a bulk roll? That could be a factor as well.

[james_megargee]

Your problem could also be with weak stop bath or fixer. Base fog with rodinal

is not an uncommon problem. But is usually caused by improper stop or fixer.

[colin_lee3]

I'm pretty sure the problem is the batch of Rodinal, since we shared everything else (stop bath, fixer) as well as the water from the tap. Winnipeg tap water is very good, and relatively low in minerals as we draw it up from a lake in the area. The 400TX was split from the same cassette, so that was consistent as well. I may need to add this to my list of unsolved mysteries, and just go buy another bottle. I'll keep the old bottle, and experiment in my spare time.

 

Thanks again for all the suggestions!

 

 

Colin

[patrick_gainer]

Out of curiousity, what is the B+F density you found? There is some inherent base density on TX, about 0.1 IIRC. You will see this when you use Clorox to remove the emulsion. Try that on a piece of leader to see the minimum you can shoot for. There can be extra fog due to exposure to heat, age, and other factors aside from developer. I did find somewhat less fog with Rodinal when I added a little borax to the 1+50 dilution.

[chris_waller]

As a user of Rodinal for twenty years I would suggest, as per many of the above, that you consider other sources for the problem. Rodinal is based on para-aminophenol which a particularly clean-working, low fog developing agent. And I've had half bottles of Rodinal sitting around the darkroom for years with no ill effects.

[oskar_ojala]

Generally I get very little base fog with Rodinal and haven't noticed any problems with Tri-X myself.