Iron Blue Toner (photographers formulary) shelf life, capacity ?

Hello, was wondering if anyone knew how long Iron Blue Toner will be usable after it is mixed. ~How many prints can I tone?

Using Fiber based paper.

Thanks in advance!

William VB said:

after it is mixed

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Generally 30 minutes or so. It starts to deteriorate pretty much instantly, especially while you're doing the actual toning. As it deteriorates, it throws down a precipitate particularly on the back of the print; initially it's still faint and washes off easily, but quite quickly it becomes a persistent stain that you need to bleach back, but this will also affect the toned image.

So I'd recommend mixing only what you need for a single print and use one shot. A flat bottomed tray just slightly larger than your print doesn't use much chemistry.