Kodak Glacial Acetic Acid or Stop Bath for RA-4

Snapshot · Jan 29, 2007

Hi All,

Just a quick question on using glacial acetic acid for RA-4 paper development. I am wondering if I can substitute Kodak Stop Bath Indicator for RA-4 paper development or is using glacial acetic acid the only option.

Thanks in advance for your input!

Nick Zentena · Jan 29, 2007

PE will know for sure but I think the indicator will cause problems. If you can find some stuff without it then it'll be okay. Personally I use vinegar.

PHOTOTONE · Jan 29, 2007

Indicator stop bath has additives that cause it to turn color when exhausted. Whether this will adversely affect the paper is unknown to me. My tabletop processor does not have a stop-bath trough, and I find no adverse effects from going directly from developer to blix, although my "older" EP-2 tabletop processor did have a stop bath trough, and it was important to use an acid stop to prevent staining in the blix. It would be best to use straight acetic acid, but you don't have to get glacial acetic acid, that is just the super-concentrated acid. You can make a stop bath from 28% acetic acid, or even grocery store distilled vinegar, which is actually acetic acid, just diluted even more than 28%.l Thus, with vinegar, you would use more vinegar in relation to water, than with the more concentrated acetic acids.

Mike Wilde · Jan 29, 2007

I've used it, but not as a preference

No difference noted on the few nights that I did this but there are cheaper ways to do it, as Nick has said. I was waiting on a shipment from Claire at JD on the nights that this happened. I ran out of the syrup as a bit of a surprise, and did not laeve time for canada post to do its job.

I used it one shot, and diluted as to the amount of acid required relative to the 8-10mL of glacial that I add to make one L of my normal one shot stop solution for home brewed RA-4. I tube precess, and rinse between stop and blix, since the home brew blix is quite dilute, and does not toloeate carried over acid well.

Snapshot · Jan 29, 2007

Well vinegar is cheap and available. What dilution (if any) is used?

Neal · Jan 29, 2007

Dear Snapshot,

Use the stop bath you normally use. Nothing special is required.

Neal Wydra

Photo Engineer · Jan 29, 2007

Use acetic acid at 2%.

There has been some concern that indicator stop bath would stain color prints. I was among those concerned, so I tested it and it worked just as well as plain acetic acid. I did not run it to exhaustion though (purple). So be careful.

PE

donbga · Jan 30, 2007

Photo Engineer said:
Use acetic acid at 2%.

There has been some concern that indicator stop bath would stain color prints. I was among those concerned, so I tested it and it worked just as well as plain acetic acid. I did not run it to exhaustion though (purple). So be careful.

PE

Ditto what PE wrote. I've used both.

Ed Sukach · Jan 30, 2007

Snapshot said:
Well vinegar is cheap and available. What dilution (if any) is used?

Usually, white vinegar is 5% acetic acid (should be noted on the container). I use it at 1% for RA-4 processing; dilute it one part vinegar to four parts of water.

I've found it necessary for uniform RA-4 processing.

Nick Zentena · Jan 30, 2007

I find in drums stop keeps the blix going longer.

Kodak Glacial Acetic Acid or Stop Bath for RA-4

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