When does Photo-Flo go bad?

[Peter Collins]

I have 2 containers--size: 1 pint (475ml) each--of Photo-Flo 200 in plastic bottles. Both are about 3/4 full. One is from 2000, the other, 2004. At the rate I use the stuff, I have enough to last a very long time. The bottles stay in a dark closet. Should I be worried about shelf life?

[paulbarden]

I have 2 containers--size: 1 pint (475ml) each--of Photo-Flo 200 in plastic bottles. Both are about 3/4 full. One is from 2000, the other, 2004. At the rate I use the stuff, I have enough to last a very long time. The bottles stay in a dark closet. Should I be worried about shelf life?

I bought a bottle two years ago, and it has an expiration date on the label that states it expires in October of 2018. I don't know what that means in terms of its usability - what DOES happen when it reaches its expiration date?? I've no clue.

[photog_ed]

I have some photo-flo that I've been using for about 50 years, and it was old when I got it. It seems to work fine.

[Leigh]

Photo-Flo is just soap. I see no reason why it would go bad.

Most likely, the expiration date on the modern bottle is just due to some regulation that requies such info on all chemical products. I would not ascribe any validity to it.

- Leigh

[Dan O'Farrell]

Photo-Flo is just soap. I see no reason why it would go bad.

Most likely, the expiration date on the modern bottle is just due to some regulation that requies such info on all chemical products. I would not ascribe any validity to it.

- Leigh

Yes, I agree.

In similar fashion, I've often wondered about the expiry date on sour cream...
what happens to sour cream after the "best before" date?:confused:

[Bob Salomon]

Yes, I agree.

In similar fashion, I've often wondered about the expiry date on sour cream...
what happens to sour cream after the "best before" date?:confused:

Probably the same thing as out of date Twinkees, like maybe 30 years later!

[ericantonio]

In a bottle it's fine. But I had it in 10 gal tanks when I worked in a lab. Eventually some type of scum forms. We added a little isopropyl alchohol to it to keep it clean and to help with drying it seems.

[tgtaylor]

Stock PhotoFlo seems to have an indefinite shelf life but I just learned that a working solution of Tween 20 (Polysorbate 20) doesn't: Last week sludge from using a 5% solution that I originally mixed in 11/15 using distilled water appeared while coating. The stock is an opaque white and I can't see if there is any stringy sludge in it like there is in the working solution. I looked it up on the wen and the shelf life of Polysorbate 20 is one year.

Thomas

[Mark Sampson]

Algae will grow in a Photo-Flo working solution, not in the concentrate. The lab where I worked c.1978 had PF tanks for their b/w sink lines that I changed every Monday morning to avoid this problem.

[Pere Casals]

Photo-Flo is not exactly soap, the active ingredient is "p-tert-octylphenoxy polyethoxyethyl alcohol", a non ionic surfactant. (MSDS sheet)

It also contains Propylene glycol, and water.

[Greg]

Am now using a glass! bottle of Photo-Flo which I bought in 1970 or 1971. Hidden behind other bottles till I did a complete clean up of the darkroom a few years ago.

[Peter Collins]

Wow, Pere, the fact that you could write out that molecule leaves me quite impressed!

[Pere Casals]

Wow, Pere, the fact that you could write out that molecule leaves me quite impressed!

It's quite straight, just google msds with the name of any product

in the safety datasheet of the product you find the ingredients...

[Willie]

When the negative influence of darkroom workers of low character are too close for too long?

[tgtaylor]

Got to thinking this afternoon about how the algae(?) growth got into the Tween 20. Could it be that it became contaminated over time from air that entered while the bottle was open when counting out drops for the sensitizer and/or not flushing out the air in the dropper when capping? The algae or whatever settles to the bottom of the bottle so if I don't shake the bottle as I normally do I could draw from the top and avoid the gunk, But at 3 years is it still good?

Thomas

[Drew Wiley]

I dunno. Used up my first and only bottle of Photoflo about 25 yrs ago. So it lasted about twenty years after opening. Then a bought two pint containers of equivalent Ilfotol, and just a month ago one of those ran out; so it lasted 25 years. It only takes a few drops at a time to do the job. So let's see ... on more pint left; so I should plan on buying another when I'm 97 years old.

Note that I just use a few drops right out of the original bottle at a time. I you store and reuse your Photoflo diluted in distilled water, then there is a risk of water mold
growth (Saprolegnia), especially in more humid climates. But the spores are pretty much everywhere. Therefore, I don't recommend re-use. Besides, your old water might accumulate little bits of gelatin or whatever. A tiny amount of Thymol Listerine mouthwash will cure the water mould issue; but I have no idea if it will have any
negative effect - perhaps staining. Dunno. I'll stick with just diluting a few drops at a time into distilled water, and then discarding it after each use.

[jnantz]

Am now using a glass! bottle of Photo-Flo which I bought in 1970 or 1971. Hidden behind other bottles till I did a complete clean up of the darkroom a few years ago.

a couple of years ago I finished my glass bottle, the label had smeared so you couldn't read a word of it and it took about 45 years to use up... I think used to be made by Timex

[Chauncey Walden]

When it is bottled. Use Edwal LFN.

[neil poulsen]

I have some photo-flo that I've been using for about 50 years, and it was old when I got it. It seems to work fine.

Ditto.

[Chauncey Walden]

It's not that Photo-Flo is unconditionally bad. it's that users don't follow the instructions and use too much of it. A little dab will do you - dab defined as a drop, two at the most. Use more only if you dare and like potentially streaked negatives.

[Luis-F-S]

I have 2 containers--size: 1 pint (475ml) each--of Photo-Flo 200 in plastic bottles. Both are about 3/4 full. One is from 2000, the other, 2004. At the rate I use the stuff, I have enough to last a very long time.

It goes bad when the bottle is empty.

[LabRat]

It doesn't go bad, but if in a bottle that was capped in an environment where contaminants were present, it could mix with solution...

PF solutions are usually mixed very strong, leaving remains as haze or tracks of liquid remains on materials, so the use of as little as possible is required... I experimented with this long ago and found the proper solution for the PF 200 stock (from bottle)... First, go to a pharmacy to get a small glass dropper bottle, and add stock 1:2 (1/3 of the dropper bottle) into it and fill the rest with distilled water... For working solutions, use 1 drop per liter in distilled water... Only allow film to bathe in solution for 30 second, as it will start penetrating emulsion and can dry with a haze once solution starts coming to surface when dry...

This can be used for prints also at half the dilution as above...

The other trick for haze free drying of materials is after washing is a final soak for at least 10 minutes in distilled or deionized water before PF bath to soak out minerals from the wash water that are deep in materials...

My experience is from using the hard water of the SW that tends to leave a mineral haze on materials...

Steve K

[Rick A]

When it is bottled. Use Edwal LFN.

Exactly

[Photodave55]

I have some photo-flo that I've been using for about 50 years, and it was old when I got it. It seems to work fine.

Still rockin the bottle I bought in 1972 or so…