Thanks Chuck. Heinz distilled white vinegar? Amazon has Glacial acetic acid, 99.9%. They also have the indicator dye as well, Bromcresol purple.
Here is a cheap way to make stop bath. Get regular old white vinegar - which is around 5-6% acetic acid - and mix it 1+4 with water to make a working solution. MUCH cheaper than the factory stop baths.
Cheaper still is to buy full strength (close to 100%) acetic acid.
Mix that 3+8 to make an approximately 28% stop bath stock
Mix that 28% stock 6/oz per gallon to make working stop bath
Just take care to have ventilation and eye/skin protection and avoid breathing in the acetic fumes. Always add the acid to the water, not the other way around.
I haven't bought factory stop bath in 40 years.
Thanks Chuck. Heinz distilled white vinegar? Amazon has Glacial acetic acid, 99.9%. They also have the indicator dye as well, Bromcresol purple.
Thanks Chuck. Heinz distilled white vinegar? Amazon has Glacial acetic acid, 99.9%. They also have the indicator dye as well, Bromcresol purple.
Do not source glacial acetic acid unless you have need for that highly corrosive, relatively difficult to handle stuff.
Heinz is probably more expensive then necessary.
Do any of our expert darkroom chemist have ideas as to how long cheap white vinegar can last on the sink line?
I know it’s easy to mix on demand but curiosity asks the question.
A casual analysis shows white vinegar based stop to be less than 1/3 the cost of comnercial indicator stop bath per gallon of working stength stop.
That's pretty much what I do for stop bath...no-name vinegar.
I would have expected maple syrup
Try adding creamed cornNope!! A litre of the tree juice costs $15! That's for my pancakes, Sunday morning! I should add that I mix up my pancakes from scratch. I like 'em thick, fluffy on the inside, crispy on the outside, topped off with bacon, butter, and heaps of maple syrup, washed down with freshly ground coffee!
Do any of our expert darkroom chemist have ideas as to how long cheap white vinegar can last on the sink line?
Same as regular stop bath because it's the same stuff.
As @chuckroast says, it depends mostly on how heavily it's being used.
If the emulsion side of the print doesn't start to feel 'rubbery' and resistant when you rub it after it's been in the stop bath for a few seconds, I consider it done for. A little acetic acid can be added, or a new batch can be prepared.
Personally I prefer citric acid for printing stop bath because it's odorless. Sprinkle some citric acid in a tray, add water and you're good to go. Another benefit is that citric acid is a trivalent acid; in practice this means it buffers quite strongly at pH's that are suitable for a stop bath. https://www.researchgate.net/figure...e-respective-pK-a-values-for-I_fig6_231742158
I assume you mean potassium hydroxide? This can indeed be used for making parodinal.Potassium hydrochloride
Pyrogallol.Pyrogallow
Pyrogallow(?), Glycin, for Ansco 130.
There's no pyrogallol in Ansco 130, though.
I assume you mean potassium hydroxide? This can indeed be used for making parodinal.
Pyrogallol.
I tried making parodinal with potassium hydroxide once. For some reason it didn't work; I ended up with a brew that was about 10% the activity of normal parodinal. I really don't know what went wrong to be honest. I made another batch not long after with sodium hydroxide and that worked fine. Don't ask me if it's due to the potassium hydroxide; I can't imagine how that would have been a problem, but one way or another, that batch didn't work.I mean potassium lye(?) which others suggest gives cleaner, longer lasting parrodinal/Rodinal mixes.
I tried making parodinal with potassium hydroxide once. For some reason it didn't work; I ended up with a brew that was about 10% the activity of normal parodinal. I really don't know what went wrong to be honest. I made another batch not long after with sodium hydroxide and that worked fine. Don't ask me if it's due to the potassium hydroxide; I can't imagine how that would have been a problem, but one way or another, that batch didn't work.
It's possible I somehow forgot to account for this; I really don't know. Kind of hard to imagine since it's a pretty silly thing to overlook, but we all make mistakes.It may be because the Potassium Hydroxide and Sodium Hydroxide have different molar weights that have to be considered when mixing your brew.
It's possible I somehow forgot to account for this; I really don't know. Kind of hard to imagine since it's a pretty silly thing to overlook, but we all make mistakes.
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