Any photo Chemists out there? FX 2

[gkardmw]

Hello,

I am reading The Film Devleoping Cookbook. Two questions about FX 2 which I think I will make from scratch:

1. How many grams of glycin for 1 liter of stock? I see both 0.75 g and 7.5 g mentioned.

2. I have K2CO3 anhydrous and the crystal form is suggested- I cannot find a source for the crystal form. I see that the reason is that some NaHCO3 is in the crystal that acts as a buffering agent. Can I just add a pinch of that to the anhydrous? If so, how much would you suggest? Thanks

 

[Ian Grant]

I have two of Crawley's original articles here in front of me. You can make the dev up as two parts and mix just before use. The concentrates are 20x stronger than the dilute formula and so are used 50ml + 50ml + 3.5ml diluted to ! litre.

The Carbonate in Crawley's experiments wasn't as pure an todays and had some Bicarbonate so I guess you could add a pinch when weighing the anhydrous Carbonate.

Ian

 

[gkardmw]

Ian, how much glycin does the article say to use? I don't suppose these articles are on-line? Maybe I am not understanding you dilution scheme, but I am reading it should be 100+100+3.5 to make 1 liter of working solution.

 

[Ian Grant]

Crawley suggest makes the stock solutions 2x as strong as in the book you have, same weights but 500ml of water, so that's why he says 50+50+3.5 to 1 litre.

Unfortunately the original articles aren't online, I have a few different sources with the information, but all written & edited by Crawley himself, the full set of 1960/1 articles, a later 1961 precis and then his reprinted versions in a few BJP Annuals.

Ian

 

[gkardmw]

Okay, the dilution makes sense. Thanks for the info.

 

[gkardmw]

I see in the chapter they are giving the amounts for a working solution and in the Appendix it was for the stock concentrates - my bad!