in my country Indonesia, it's hard to find Disodium phosphate, can change it to trisodium posphate?
Hallo- I just JOINED this Venerable Site ! I love mixing my own ever since 1951 when the School Chemistry Master showed members of the School Photo-Soc how to mix up developers ! I tried this Formula today with some 1992 dated Kodak TMY 400 I downrated to 250ASA -- I mixed a x3 concentration, then I diluted it 1+3 with water -- was my maths corect as the test length of 120 film was severely under-developed at 10 minutes (guessed time) and I was careful to use 18oC not the usual 20oC. Regards to all the Experts on here, from Darkest Essex, England -- Peter.
Hello pentaxpete and welcome to APUG.
I did the other half of the cut 120 film-- this time I rated the film at 200ASA and gave it 17 minutes instead of 10 minutes -- result -- better, but still a bit 'thin' and I think it needs at least 18 minutes dev time and rate at 160 ASA.
hello, for 3x concetrate you should make up the working solution by diluting it 1+2 with water (1+2 dilution = 1:3 = 1/3 concentration). however, don't be afraid to prolong the development further, this developer is softly working. maybe you will have to add more Disodium phosphate to it for 18 years old film (10-20 g maybe, maybe more).
Dear Mr Lucas : many thanks -- your MATHS is much better than mine ! I asked my boy and HE said it should be 1+2 not 1+3 as I worked out -- I am experimenting more with the developer, will try with some other films -- the FOG level on my outdated TMY 400 was very low , so looking promising ! ( just one worry -- MY bottle says 'Disodium Hydrogen Phosphate' -- is it the same as the ordinary 'Disodium Phosphate' ? )
I think it should be all right as long as your Disodium Hydrogen Phosphate is Na2HPO4 . 12H2O (CAS: 10039-32-4). It's the same I think (or hope).
Best Regards from the Czech Republic!
I have nothing to say except thank you to the contributer.