Acidifying paper with stop bath?

[Akki14]

Has anyone tried to acidify paper with stop bath(B&W process usual stuff) solution? I think it'd work out cheaper than me buying bottles of vinegar :confused: And I'm assuming the indicator doesn't stain the paper. I guess I could try it out and tell you all but that'd be less fun than asking

 

[pentaxuser]

Fotospeed's acetic acid stopbath at 1:29 is certainly cheaper than I can buy vinegar. A litre at about £6 makes 30 litres of stopbath. That's fractions of a penny per print and it has an indicator which is harmless to prints.

Citric acid as opposed to acetic stopbath is comparatively odourless but more expensive. You might be able to buy citric acid powder from Homebrew shops and I think Silverprint in London relatively cheaply. It doesn't have an indicator. Someone may suggest how many prints you can do per litre of working solution but generally, if in doubt throw out as it is cheapest liquid you'll use with the exception of water.

pentaxuser

 

[Akki14]

Unsurprisingly, It's Fotospeed's acetic acid stopbath I have on hand. I have some citric acid from Silverprint too but I don't go to Silverprint too often and homebrew shops aren't too nearby either. I'm just trying to unbuffer/un-acid-free the watercolour paper I have so I can coat it with cyanotype sensitiser(after drying).

We have really awful super-hard water so maybe I should pre-rinse after exposure with the stop bath too. I had been doing a mix of 50/50 water and vinegar (so it comes out to be about 2% acidity) in a tray to slosh the paper around in until the unused sensitiser comes off the paper.