Yellow fixer causing issues in roller transport machine?

[Tom Kershaw]

For over a week or so I've been running a Thermaphot ACP 505 most days using ILFORD 2000RT paper developer and Champion Amfix diluted 1+4, replenishing the machine manually with 2000ml volumes a couple of times, including today. Returning to print today after last use on Wednesday evening, I found brown roller type stains on the 5 or 6 8x10" prints put through before I decided to investigate. Upon draining the solutions to clean the machine with warm water, I noticed the fixer exhibited a moderate yellow colour which I suspect is problematic. Reviewing the Amfix instructional label, a 1+2 dilution is suggested for roller transport paper applications; possibly the fixer @ 1+4 dilution isn't sufficiently buffered against the developer as there is no stop bath?

In a possibly connected factor, the last of the 3 roller racks of the wash section exhibits a black deposit across the whole length on two rollers; possibly mold?

Tom

 

[Mike Wilde]

I fly a fuijimoto cp31 and I always drain it and wipe down the rollers with a moist j cloth after running the whole machine on a water rinse. It is possible to review pH and adjust it for nay carry over affect, as you indictate. I hate to say it but black stuff on rollers is usually rubber starting to break down, and the fix is never chaep when it comes to rollers. I love my CP-31, but have kept tubes to go back to for the day when it dies a death I cannot salvage it from.

 

[Tom Kershaw]

Mike,

See:

Tom

 

[Photo Engineer]

Tom;

Check the black deposit to see if it dissolves in Blix or Dichromate - Sulfuric acid tray cleaner. If it does, it is silver! If it does, your fix is not working right. Of course, it could also be a very heavy deposit of carryover developer due to the lack of stop. This is especially possible if you have run much FB paper, but you are apparently not doing this.

PE

 

[Tom Kershaw]

PE,

I've not put any fibre base paper through the machine, but based on your comment, could it be the fixer went bad, (hence yellow colour) due to lack of a stop bath step, resulting in silver deposits? In the ACP 505 there are five tanks: -> dev, fix, wash 1, wash 2, wash 3 (location of deposits on roller). There are no similar marks or deposits on other visible rollers.

Perhaps I should only use a fixer sold for machine processing specifically, e.g. the ILFORD 2000RT fixer.

Tom

 

[Photo Engineer]

Tom;

Fixer pH rises due to carryover of developer. Developing agent oxidizes in the fixer and reacts with sulfite to form sulfonates. Some of these things even form polymers, and all of them gradually yellow. Sulfides form and silver can precipitate out as black gunk. I could give you dozens of possible things. You have used a weak fix to start with, and no stop. This is the worst possible position and the presence of the black gunk is not helping things.

It is hard to diagnose from here, because of all of the possible things. All I can do is point out several possible paths things might have taken. I've just given the most likely. I'll mention another just for kicks. Matte paper uses either starch or poly methacrylate beads in the surface layer and this can sometimes leave a deposit on rollers which can blacken or discolor as they absorb chemistry.

PE

 

[Tom Kershaw]

PE,

Thanks very much. I've only put through a very few sheets of matte paper but hundreds sheets of glossy black & white RC and Kodak F-surface RA-4 paper. I'll investigate the black deposits and next time I run a batch of prints though, I'll either use the Champion Amfix @ 1+2 dilution or get in stock a supply of 'machine' fixer.

Tom

 

[Tom Kershaw]

An update:

Although I've not run a batch of prints through the machine since my last post on this read, I have tried cleaning and soaking the roller(s) in Kodak RA blix with positive results, i.e. the "gunk" is dissolved; however some residual staining does still appear to be present. A remaining question is why the thick deposits (which oddly appeared to increase before blix soaking) appeared on that particular roller...

Tom

 

[RobertV]

Perhaps I should only use a fixer sold for machine processing specifically, e.g. the ILFORD 2000RT fixer.

For the Thermaphot 2 bath machines I always used a regular acid fix 1+4 on 30 C.
The grey rollers should be completely clean.
When the rollers are not good anymore you can have dichroitic fog with these machines. Yellow stains on the paper.
Also most regular paper developers can be used on 30 C. The time for developer and fix is then 2x30S.
But again the rollers should be clean. After using the machine you have to rinse all rollers with water.
When not using for a few days you can chance the chemicals for water and rinse.

Robert