Cleaning RA4 Tar deposits

BMbikerider · Aug 4, 2016

Those who use RA4 for colour prints will find after a while contamination with tar from the developer. I have just found today that the highly concentrated stop bath sold under the Kodak name with the catalogue number of 516 0346 is just the thing to get rid of it. Basically it is Acetic Acid but not in the highly concentrated form

You will have to wear surgical gloves and do it in the open air because of the fumes, but a small amount poured onto a cleaning cloth and wiped over the surface which is contaminated, will remove almost all but the very old stains. It takes no vigorous rubbing to shift the tar, just a gentle wipe over and rinse it off.

Brilliant stuff and inexpensive too.

EdSawyer · Aug 4, 2016

So, Kodak indicator stop bath? Toilet bowl cleaner is supposed to work pretty well too.

BainDarret · Aug 4, 2016

I seem to remember using Isopropyl Alcohol to clean up RA4 tar when I had a Durst Printo.

Mick Fagan · Aug 4, 2016

BMbikerider said:
Those who use RA4 for colour prints will find after a while contamination with tar from the developer. I have just found today that the highly concentrated stop bath sold under the Kodak name with the catalogue number of 516 0346 is just the thing to get rid of it. Basically it is Acetic Acid but not in the highly concentrated form

Very pleased to hear, but is the Acetic Acid highly concentrated or not?

Your writing does seem to contradict itself.

Mick.

MattKing · Aug 4, 2016

If I understand correctly ...

Kodak Indicator Stop Bath (516 0346) includes a mixture which includes a fairly high concentration of Acetic Acid, but not as concentrated as Glacial Acetic Acid.

If you spill the concentrated Kodak Indicator Stop Bath on something like a laminate counter, it can damage the counter.

Photo Engineer · Aug 4, 2016

Any moderately strong acid will do!

PE

BMbikerider · Aug 5, 2016

1. I use toilet bowl cleaner to do just that, nowt to do with photography. So Not applicable.

2. Isopropyl alcohol is only obtainable from wholesalers now and in fairly large quantities. So Not applicable.

3. The acetic acid in the stop bath is not in the Glacial form but still fairly concentrated and has a pungent odour. Kodak recommend a 1-63 dilution for photographic purposes. For cleaning I use it neat!

4. I have no intention of spilling it on any laminate surface, the cleaning is done outside. So not applicable
(although it did remove rust stains from my bath when I tried it, and certainly didn't stain the surface!)

5. I do not have access to Sulphuric, Hydrochloric, Phosphoric acid, or indeed any other acid apart from citric which I consume with an orange or two. This form of acetic acid is effective, plus it is far easier to obtain and use. Added to which, it washes off easily and doesn't contaminate the processor afterwards.

AgX · Aug 5, 2016

Photo Engineer said:
Any moderately strong acid will do!

PE

Likely 25% acetic acid available here at supermarkets.

pentaxuser · Aug 5, 2016

I have never seen 25% acetic acid for sale here in the U.K. supermarkets. As I recall it the price of Kodak stop was quire reasonable here in the U.K. and it sounds as if not a lot of it is needed at full strength to do the job BMbikerider describes.

So a bit of good advice for U.K. users who can buy the Kodak stop for its main use as well and quite cheaply.

pentaxuser

BMbikerider · Aug 5, 2016

Perhaps you haven't seen it because AgX lives in Germany. We possibly have more stringent controls in UK over what is a really nasty substance, even at 25% solution! (Known as C.O.S.H. Regulations or Control of
Substances Hazardous to Health) It may not be generally available to the public at high concentrations.

darkroommike · Aug 5, 2016

In the USA...Kodak Indicator Stop Bath is 28% Acetic acid with indicator, you could also use 28% Acetic acid without indicator which I used to make from Glacial Acetic acid by dilution. 90% and 70% Isopropyl alcohol are sold in drug stores in the USA, ISO Heet (trademark) is even stronger Isopropyl and sold in automotive supply stores for "drying" the water out of gasoline.

But when cleaning roller transport machine racks in our Hope C41 and RA4 machines we used Lysol Toilet Bowl Cleaner (factory recommended). MSDS has it with hydrogen chloride, Alcohols (C12-16, ethoxylated), and Ethoxylated aliphatic amines. HCl in solution is hydrochloric acid which is what clears the calcium build up in the toilet bowl and I suspect is the primary tar dissolver, the other ingredients are fecal sanitizers.

Photo Engineer · Aug 5, 2016

White vinegar + time will work as well in most cases!

PE

darkroommike · Aug 5, 2016

Yup and that's what I would use now, I no longer have to scrub down 26 roller transport racks once or twice a week. I don't mind the smell of acetic acid, but some folks find it an irritant. (Just take it outside for better ventilation.) USA white vinegar is a 5% solution of acetic acid (made by distillation). In some other countries it's stronger.

stefan4u · Aug 14, 2016

Do you have access to citric acid? In Germany you can buy it in every drugstore, approx. 400 grams. Solve it to a liter of water, add a liter of spiritus (denaturized alcohol) and than add half a liter of a cheap bathroom/tilt cleaner (NO Clorox!!, just tensides/surfactants). In total 2 1/2 Liter.

That gives a wonderful RA4 Machine cleaner, smells bad because of the denaturized alcohol, may be flammable (38-40% Alc / per liter), but used with precaution this is a cheap and reliable cleaner against RA4 tar buildup in developing machines. It will be perfect for “hand use” too...

Wear gloves and goggles, ventilate your space well and rinse good after use.

All the best, stefan

Cleaning RA4 Tar deposits

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