what waS your last photography related purchase?

[What About Bob]

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.

 

[chuckroast]

Thanks Chuck. Heinz distilled white vinegar? Amazon has Glacial acetic acid, 99.9%. They also have the indicator dye as well, Bromcresol purple.

Yup to both Heintz and Glacial.

I have never used indicator. Stop bath made this way is so cheap, I use it for only one printing session and never use it for film.

 

[MattKing]

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.

 

[eli griggs]

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.

 

[chuckroast]

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.

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.

I agree that using acetic acid should only be attempted if one is comfortable handling acids and has the required ventilation and personal protective equipment.

 

[chuckroast]

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.

Depends on volume in the tray and how careful you are to minimize developer carryover.

I use 64oz stop per session for up to 11x14 prints and up to 6 hours. I am making mine from acetic acid but the working capacity should be the same for properly mixed vinegar - 1ish % acetic acid either way.

 

[Don_ih]

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.

Even cheaper if you use some non-name store brand vinegar. I routinely find 4 litres of vinegar for a couple of dollars.

 

[Andrew O'Neill]

That's pretty much what I do for stop bath...no-name vinegar.

 

[chuckroast]

That's pretty much what I do for stop bath...no-name vinegar.

I would have expected maple syrup

 

[Andrew O'Neill]

I would have expected maple syrup

Nope!! 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!

 

[MurrayMinchin]

Nope!! 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!

Try adding creamed corn

 

[tokam]

Definitely yummo to the bacon, pancakes and maple syrup!!

Back on topic, John Finch of Pictorial Planet released a video on making an indicator stop bath using vinegar and bromcresol green dye.

 

[koraks]

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

 

[Ian Grant]

I bought the Exa 500 on the right for £1, it came with the 2x converter (middle) attached, which is in excellent condition. I removed and swapped the rewind lever as the lever on the IA (on the left) was missing.

I am trying to downsize and sell, but it helps if nothing is missing and everything works well

Ian

 

[eli griggs]

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

Good tip.

 

[mshchem]

After yesterday's darkroom session I should be buying tranquilizers! I'm hoping I receive a series VIII filter adapter in tomorrow's mail. No purchases for me. Maybe a cheeseburger.

 

[eli griggs]

Potassium hydrochloride for Rodinal/parrodinal, Pyrogallow(?), Glycin, for Ansco 130.

 

[Pioneer]

Another 100 foot roll of Arista EDU Ultra 400. Love the grain in PaRodinal. I could shoot this film exclusively for the rest of my life and be happy.

 

[koraks]

Potassium hydrochloride

I assume you mean potassium hydroxide? This can indeed be used for making parodinal.

Pyrogallow

Pyrogallol.

 

[Don_ih]

Pyrogallow(?), Glycin, for Ansco 130.

There's no pyrogallol in Ansco 130, though.

 

[eli griggs]

There's no pyrogallol in Ansco 130, though.

Yes, the pyrogallow is for another developer and supplies cabinet.

I assume you mean potassium hydroxide? This can indeed be used for making parodinal.

Pyrogallol.

I mean potassium lye(?) which others suggest gives cleaner, longer lasting parrodinal/Rodinal mixes.

You'll have to bear with me and my spelling, I get a lot of it wrong, but, you guys/gals keep me on track when I don't have the formula spelled right.

I forgot fixers when I placed my order last night, so that's next.

 

[koraks]

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.

 

[chuckroast]

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 may be because the Potassium Hydroxide and Sodium Hydroxide have different molar weights that have to be considered when mixing your brew.

 

[koraks]

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.

 

[chuckroast]

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.

I did the math just to satisfy my curiosity...

Parodinal calls for 20g of sodium hyroxide which has a molar weight of 40g/mol

So that works out to be 0.5mol of NaOH.

Potassium hydroxide as a molar weight of 56.1g/mol.

0.5mol of KOH is thus 28.05g.

This assumes they work identically in the developer and all you have to do is achieve an equivalent reactive amount.

I have now exhausted my 50+ year old chemistry knowledge and am more than open to being refuted or corrected