white vinegar as stop bath

RalphLambrecht said:

2% IS OK BUT i prefer citric acid these days.

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But not with color I hope!

oldtimermetoo said:

PE, somewhere deep in my memory, I read or someone told me that industrial white vinegar could be made as a by-product of the petroleum refining industry and they somehow by-passed the fermentation step in making it. Have you ever heard of this?.......Regards?

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Hah! Almost any organic chemical can be made from petroleum by changing conditions. Pretty messy and expensive I would imagine. Fermentation is easier and cheaper.

Some fermentations do give methanol and then formic acid. Don't use these types if you are a do it yourself type. Just buy the vinegar.

PE

Vinegar is quick and easy to pick up at the market.

It could be cheaper or more expensive than the manufacturer's own brand of stop but my market doesn't have any other brand of film stop on the shelf.

Vinegar works great and harms no one. It is one less thing I have to worry about buying on line and when disposing.

Glacial Acetic Acid may be useful as well but vinegar fumes do not catch fire and flashback, burn my respiratory tract or burn other parts of my body if spilled.

Finally, it is very useful in the kitchen as well.

Anon Ymous said:

PE has said that citric acid based stop baths shouldn't be used in a C41 process, only acetic ones.

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go with that;he knows what he's doing!

White vinegar is a distillate of grain alcohol fermented by acetic acid bacteria. In the US it is usually 5% but can be stronger in other countries (read the label). It is the only vinegar that should be used for a stop bath except in an extreme emergency. Also useful for general cleaning so I always have some around. I dilute it to 1-1.5 per cent for tray use with paper, I use a water rinse for film. Per tray of working solution it's not much (if any!) cheaper than 28% but I can get it locally and not have it shipped.