Can you tell me precisely what kind of "EDTA" this was? Was this a sodium salt of EDTA by any chance?
I added the ferric chloride before the ammonium bromide, what happened then? The EDTA precipitated, I added ammonia again little by little and the precipitate disappeared. I have a dense red solution. My question is, will it still work or should I start again from scratch?
Can you tell me precisely what kind of "EDTA" this was? Was this a sodium salt of EDTA by any chance?
I had disodium EDTA stored that I did not use, I obtained free acid EDTA by the method you proposed, once washed and dried this was the EDTA that you used.
To prepare the bleaching solution I added the EDTA, which did not dissolve, and added ammonia little by little until it dissolved, the pH rose to 5.3, after that I added the ferric chloride and the low pH until 1, more or less, then a precipitate was formed again, I added ammonia again until it went up to pH 4 where everything was dissolved.
Ah, ahora tiene mucho más sentido. Sí, el EDTA entra y sale de la solución dependiendo del pH. Esto lo hace mucho más fácil que, por ejemplo, el cloruro férrico, que no se disolverá fácilmente una vez que se precipita el hidróxido férrico. Su procedimiento fue un poco más complicado que el de mis instrucciones, pero le dará el producto correcto y una vez que tenga el acelerador de cloro podrá trabajar con él.
Yesterday I called a local supplier to see if they had ammonium bromide available, not only did they have it available, they had it at a great price.Ah, ahora tiene mucho más sentido. Sí, el EDTA entra y sale de la solución dependiendo del pH. Esto lo hace mucho más fácil que, por ejemplo, el cloruro férrico, que no se disolverá fácilmente una vez que se precipita el hidróxido férrico. Su procedimiento fue un poco más complicado que el de mis instrucciones, pero le dará el producto correcto y una vez que tenga el acelerador de cloro podrá trabajar con él.
Yesterday I called a local supplier to see if they had ammonium bromide available, not only did they have it available, they had it at a great price.
Which reminds me - would you mind having a look at this thread please, and perhaps, if you can, share some advice with your fellow countryman? https://www.photrio.com/forum/threads/darkroom-chemicals-in-mexico.205936
I studied a little more about L-Cysteine and compared it to the other bleach accelerators discussed earlier in this thread, place a developing slide film in the first developer and then apply a stop bath so you can cut a small strip and continue with the process. Once the pre-bleach was applied, without washing, I put the film in the bleach and monitored the bleaching process with an open tank. The result? The film was completely bleached within 3-4 minutes. After developing the strip and getting good results, I developed the rest of the film, right now it is drying, I still need to do more tests with different films and make a comparison between L-cysteine and thioglycolic acid but I imagine that if I had not worked the L-cysteine bleaching would not have been carried out and I would end up with a very dense slide, or not? L-cysteine has the advantage, like Mercaptotrizole, of not having an unpleasant odor.
I would be interested too. This Mercaptotrizole chemical is €15 for 5g, but probably one gram will be unusable due to its volatility.
Looking forward to read your results from Thioglycerol vs. Cysteine!
@Josaw98 great to hear, that the experiment went well, and it's even greater to hear, that Cysteine does the job well! One potential risk with Cysteine could be longevity of the working solution. I believe I have read somewhere, that Cysteine is a reducer, which may well react with aerial oxygen. But I can imagine many cases, where a Cysteine based prebleach freshly mixed is still a lot less hassle than jumping through the burning hoops to obtain Thioglycerol or Mercaptotriazol.
@lamerko if the smell of prebleach is an issue for you, then try to get Mercaptotriazol from Suvatlar. It's is known to work well and it's completely odorless.
@Josaw98 you can use an ICE capable film scanner to roughly check for retained silver. At least in vuescan I am able to obtain a histogram in the IR channel, and over 90% translucency in the IR channel indicates good desilvering of the film.
One of the tests mentions that L-(+)-cysteine hydrochloride 6 g was added to the bleach. The rest have a pre-bath, where the pH should be quite low. Maybe I'm wrong, but I guess you need cysteine in both the pre-bath and the bleach?
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