life of photo flo

[LabRat]

I had tested different dilutions of PF many years ago for making fresh smaller amounts when needed... I was finding even a very small excess of PF 200 solution easily led to scum artifacts on film as well as bubbling, and too little didn't sheet/wet evenly so did tests...

Long process short, I arrived at a convenient dilution of the 200 stock by first getting a glass dripper bottle from the drugstore, then diluting the stock 1 part stock to 2 parts distilled water in the dropper bottle... For working solution, add 1 drop from dropper bottle into 1 liter of distilled water for film final dip for 30 seconds (don't leave in too long as the wetting solution starts to soaking into film and can dry blotchy)... And for prints, 1 drop per 2 liters with 30 second dip...

PF tends to leave a haze on clear film areas if too strong/long, and a haze can be seen on low key prints, but I also photo sponge roll films and prints slowly... Sheet films tend to dry evenly, but sometimes a drop starts to dry with a drying mark or a bottom edge, but a quick blot to the drop before dry does the trick in this hard water area...

Steve K

[Edward Pierce]

I mix Photo-Flo in distilled water and keep it in a glass bottle and use it multiple times. Before using I hold the bottle up to a light and swish it around. If it’s completely clear it’s ok to use again. Eventually, stringy gunk appears and it’s time to mix a new batch. And...I use half the recommended dilution.

[Drew Wiley]

It takes so darn little of it to get the job done that is see no need to pre-mix anything. A drop of two of Photoflo or equivalent per liter or half liter of distilled wter. All it really needs to do is break the surface tension of the water droplets. Water mold develops quickly in Spring or Fall weather, even in distilled water exposed to the air; there's nor reason to tempt that.