Black marks on RA-4 Prints

yelmarb · May 15, 2022

I've recently purchased a Fujimoto CP-31 processor and after spending a full day cleaning it (Tetenal Tar Remover, brushing, and about 20 rinse cylces) I'm getting what seem to be silver deposits on the prints. They're happening in the blix and it seems to be crystals of silver forming and then attaching to the print - that's my guess, completely open to suggestions.

Has anyone had this issue?

pentaxuser · May 15, 2022

Someone will ask these questions so I might as well be the first. Are these black spots on every print including the first and are they in different places on each print?

Have you tried processing a print by another means such as tray developing to check if there is still contamination in the processor? Does the inside of the processor look to be completely free of any old deposits of chemicals?

Are these black spots embedded in the prints and cannot be wiped or washed off.

Was the developer and blix freshly made just before being poured into the processor? How old is the blix?

Tiresome as it may be I'd certainly try printing without the processor to see if this eliminates the spots If it doesn't then this suggests that there are deposits in the blix which are being poured into the processor

pentaxuser

mshchem · May 15, 2022

Yeah, everything that pentaxuser has mentioned. I would try running a completely fixed, washed and dried blank sheet of paper through. Try to figure out if the print is picking up tar, or some other contamination.

I have a little baby Durst RCP, max width is 8 inch, I don't even let it sit overnight with chemistry.

yelmarb · May 15, 2022

Thanks for the replies, I have used new blix made up from brand new chemistry. Before adding the chemistry, the machine was spotless.

The dark spots come from the rollers and will stick to the prints regardless of whether they’ve been processed previously or not (I’ve tried and blank sheet of paper). They’re not always in the same place as one print picks them up and the next print they’ll be in a different place.

The spots can sort of been smudged off the print with water but I can’t remove the stain completely.

I do have an RCP20 processor which I’ve used the same chemistry in and not had this problem. However I was using a stop bath. For the Fujimoto CP31, I’ve gone without the stop bath and just dev, blix, wash.

My theories so far is that the machine’s plumbing still has old silver residue that’s now being stirred up by being used (despite having a full degrease and 20 rinse cycles). Or that there’s some reaction happening from the dev and then going straight into the blix.

AgX · May 15, 2022

What about the deposits being of roller material?

MattKing · May 16, 2022

AgX said:
What about the deposits being of roller material?

+1

yelmarb · May 16, 2022

Thanks for the reply @AgXI’ve put about 40-50 prints through it and the marks are still coming up in random places on the prints. If it was the roller material then I would expect the marks to be in the same place on each print.

Has anyone had the same sort of marks on their prints?

AgX · May 16, 2022

yelmarb said:
Thanks for the reply @AgXI’ve put about 40-50 prints through it and the marks are still coming up in random places on the prints. If it was the roller material then I would expect the marks to be in the same place on each print.

Not if the rollers are in a deteriorating state with constantly giving off solid ot smeary (tar) particles. I am ignorant on the Fujimoto rollers, but I have seen one photo showing at least one black roller.

foc · May 16, 2022

The easiest way to check for roller deterioration is to run your finger tip along the roller. If you have any particles/spots on your finger then that would appear to be the problem.
If so then a new set of rollers is required.

yelmarb · May 16, 2022

foc said:
The easiest way to check for roller deterioration is to run your finger tip along the roller. If you have any particles/spots on your finger then that would appear to be the problem.
If so then a new set of rollers is required.

When I run my finger tip hard across the rollers I do get some dark staining on my finger from the rubber dev roller. Tried to wash the roller out but the tar is embedded in it.

The blix roller, which is where I've seen what looks like silver deposits at the bottom of the tank after a print session, has cleaner rollers.

Wouldn't a deteriorating roller create a wider pattern of tar staining on the print rather than irregular spots?

AgX · May 16, 2022

When acquiring a roller processing device from the heydays one should calculate roller refurbishing into it.

pentaxuser · May 16, 2022

yelmarb said:
When I run my finger tip hard across the rollers I do get some dark staining on my finger from the rubber dev roller. Tried to wash the roller out but the tar is embedded in it.

The blix roller, which is where I've seen what looks like silver deposits at the bottom of the tank after a print session, has cleaner rollers.

Wouldn't a deteriorating roller create a wider pattern of tar staining on the print rather than irregular spots?

If it is the roller then provided it is not actually crumbling, it might be worth removing it and immersing it completely in fairly strong bleach. In my experience bleach will remove almost anything given several days.

I don't think there is anything in bleach that is liable to damage a roller. If that doesn't work then you might want to consider stuff called Tar Buster sold by the Imaging Warehouse. It is incredibly strong and needs to be applied wearing a mask and gloves

It might be worth a call to the company to ask whether it has a deleterious effect on rollers. Here's the link

Nova Tarbuster Darkroom Cleaner Stain Remover - The Imaging Warehouse | Nova Darkroom & Digital Inkjet Supplies

So it sounds fine as it specifically states it is for roller transport racks. At £12, not as cheap as bleach but it should do for a few cleans

pentaxuser

foc · May 16, 2022

yelmarb said:
When I run my finger tip hard across the rollers I do get some dark staining on my finger from the rubber dev roller. Tried to wash the roller out but the tar is embedded in it.

The blix roller, which is where I've seen what looks like silver deposits at the bottom of the tank after a print session, has cleaner rollers.

Wouldn't a deteriorating roller create a wider pattern of tar staining on the print rather than irregular spots?

RA4 developer shouldn't throw up much tar. If there are tar deposits on the roller then remove then and clean them with methylated spirits. Ideally let the rollers sit in a bath of the methylated spirits for an hour or so then wipe with a cloth.
If the rollers surface is breaking down then the only solution is replacement.
BTW, do you filter and reuse your chemicals?

AgX · May 16, 2022

pentaxuser said:
So it sounds fine as it specifically states it is for roller transport racks. At £12, not as cheap as bleach but it should do for a few cleans

Buying the refill instead should yield some saving, though that dealer veils volumes...

Black marks on RA-4 Prints

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