Replacement for Pinakrytol Yellow in FX-2

[Arthur Nichols]

Hi,
Can one of the chemistry gurus suggest a replacement for the use of Pinakrytol yellow in FX-2? It seems that Pinaktyptol is no longer available from PF. I know that I can substitute Potassium Bromide (I use 10% solution), however I don't know how much to substitute per liter.
Thanks
Art

[Ole Tjugen]

You can simply ignore it. The recommendation is to mix it without Pinakryptol for T-grain films; and it works fine for other films too without the Pinakryptol.

At the cost of possibly a little bit more fog (although I haven't noticed this problem) you save having to obtain and mix an expensive chemical. I have 1 gram of Pinakryptol yellow, but haven't used it for FX-2. I have used FX-2 though - it's a great developer for stand development too!

[CP Goerz]

I thought the pinakryptol was to render the film insensitive to light for development by inspection? I thought that stuff disappeared in the 1930's!

[Ole Tjugen]

Pinakryptol has several uses, and one of them is as a desensitiser. Another is as an anti-fogging agent in some developers, like FX-2. I'm not really sure it's an anti-fogging agent, but I'm sure Crowley had a good reason for putting it in there!

It also has quite a few non-photographic uses, so it's still available through good chemical supply houses.

[Arthur Nichols]

According the film developing cookbook pinakrytol is used as an antifogging agent.
Thanks for the suggestion about not using it but I have already tried this and the fog is definitely higher than without it. I want to make some large enlargements and in order to keep the printing times reasonable I would like to limit the FB+F. If anyone else can provide a conversion factor it would be great.
Thanks
Art

[Colin Graham]

I wonder if some benzotriazole would work. I mainly use it for paper, but it might work for film too?

[Donald Qualls]

Benzotriazole *does* work for film. So does potassium bromide.

Most likely FX-2 calls for pinakryptol yellow because it works by a different mechanism and thus has less disruptive effect or changes required developing time less than bromide or BZT, or some other good reason.

FWIW, I seem to recall pinakryptol yellow and pinakryptol green being related, one changes into the other with a change of pH -- can you still get the green and convert it, perhaps? Alternately, a combination of BZT and bromide might well do what you want.

[Arthur Nichols]

I was hoping that Sandy King or Pat Gainer might weigh in on this. I can't be the only FX-2 user out there with this issue. I know that I can experiment and have done so with the Pottasium Bromide but I still do not have a definitive amount per litr.

[Donald Qualls]

Other formulae that use bromide alone as a restrainer typically run around 5 g/L in working solution. FWIW.

[sanking]

Hi,
Can one of the chemistry gurus suggest a replacement for the use of Pinakrytol yellow in FX-2? It seems that Pinaktyptol is no longer available from PF. I know that I can substitute Potassium Bromide (I use 10% solution), however I don't know how much to substitute per liter.
Thanks
Art


As a guide I would recommend about 10 ml of your 10% potassium bromide solution per liter of working FX-2. Look at your results and increase or decrease the amount of bromide as required.

You might also try potassium iodide at about 1/100 the amount of bromide. Crawley recommended it for FX-1 for traditional films.

Sandy King

[Uli Mayer]

The fact that Pinacryptol Yellow isn't sold any more by PF does not mean that this dye disappeared altogether. It is still available elsewhere:
http://www.diagonal-shop.de/version02/englkatalog.pdf
My knowledge in chemistry is rather poor; but as older photo books list more than one substance suited for de-sensitizing, a bit of research might unearth readily available and almost indentical substitutes for Pinacryptolein: pheno-safranin for example is frequently used in bio labs for dyeing tissue specimens.

[Helen Bach]

Here's what Geoffrey Crawley wrote in the BJP, Jan 6, 1961:

"...Such a metol-glycin developer is FX-2, which may be used, diluted, as a stand developer. In this formula, a dye restrainer is used to ensure clarity of fine detail. Dye restraint seems often more efficient than bromide in discriminating between exposed and unexposed crystals – ie it can give a faintly higher image-to-fog level; it may also be used to reduce grain clumping in some developers (cf the use of phenosafranin in this context). Dyes probably have some effect on the supply of oxygen in the developer; hydroquinone, which will hardly develop in the absence of oxygen, is strongly energised by some dyes. Their ability to render unexposed silver halide undevelopable is of course the basis of their use as desensitisers. They have also been used in small quantities to prevent aerial fogging in dish developers (a use analogous to that in FX-2)."

There's a thread over on APUG ( http://www.apug.org/forums/showthread.php?t=22967) about dye restrainers and desensitisers.

Best,
Helen