Kodak provided a "teaching patent", i.e. a publication for preservation of knowledge, for their 5 liter E-6 home processing kit. The original patent text can be seen here. While anyone with access to these formulas and ingredients could start mixing and using, this article tries to make these formulas more accessible to amateurs. Please note, that all liquid ingredients except for dilute aqueous solutions and water are given in...
Dear Rudeofus, Are you planning to provide similar details for the remaining E6 baths (bleach, fix and rinsing)? Chris
The official formula for bleach provided by Kodak is of little use to us, since it relies on HBr (Hydrobromic Acid) solution. I do plan on posting my own formulas for bleach and fixer at some point. Regarding final rinse: Ron Mowrey (aka PhotoEngineer) posted a decent final rinse formula.
Conc. HBr is a stronger acid by pKa, but not really more difficult to handle than conc. HCl. Obviously you need to be able to do that safely. But I don't know what steps in particular are part of that Kodak recipe.
There are no particularly onerous restrictions on the purchase of HBr solution. In Europe, at least. After all you can buy HCl solution as well.
A copy of your ID will be needed for proof of age and that is pretty much it. I can see it at a German dealer I have used a couple of times (S3) and I can see it at a Dutch online shop which I am considering to try out soon. Apparently you can buy up to 100g of KMnO4 as a private individual.
If you want to make a violent thug regardless of cost,
@Rudeofus - is "violent thug", perhaps, an example of auto-correct run amok?
If you need help editing it, just ask!
It also contains a significant amount of hydrobromic acid. I'd be *very* hesitant to consider handling this in a typical home lab. I'd consider that particular formula for educational purposes and not for home-made use.Dear Rudeofus, Regarding the bleaching formula in the patent, it contains potassium nitrate, which is not available to individuals in China because it is a dangerous controlled substance. I was wondering if there are any alternatives to potassium nitrate.
It also contains a significant amount of hydrobromic acid. I'd be *very* hesitant to consider handling this in a typical home lab. I'd consider that particular formula for educational purposes and not for home-made use.
This ingredient is mainly to increase bromide ions and lower the PH value.
I think what is more difficult to understand in this patent is the pre-bleach solution, because it still uses formaldehyde, but all the brands of solutions sold actually use 870-72-4
I think you're probably right. It also has the advantage of not introducing any unnecessary or unwanted alkali ions, although I doubt that this is very significant.
Modern E6 processes don't require a stabilizer step at the end of the process because it's been made part of the pre-bleach bath. So that's why the formaldehyde is there. I guess commercial chemistry doesn't use straight formaldehyde to prevent workers and consumers to be exposed unnecessarily to formaldehyde fumes.
Formaldehyde Bisulfite Adduct, which is here mentioned as "870-72-4", will obviously work as replacement for Formalin ;-) The Formalin in the article's recipe will obviously form the same compound together with the Potassium Metabisulfite.
Formaldehyde Bisulfite Adduct, which is here mentioned as "870-72-4", will obviously work as replacement for Formalin ;-) The Formalin in the article's recipe will obviously form the same compound together with the Potassium Metabisulfite.
so I am commenting on an error when using sodium bisulfite
As you can see, the Fuji bleach recipe has Sodium Sulfite as an ingredient, just about every E-6 bleach formula also has Na2-EDTA as ingredient. Small amounts of sodium salts obviously don't cause problems. What Kodak warns against are prebleaches with "high sodium content". The prebleach formula I derived from Kodak's patent is quite dilute and would therefore definitely not qualify as "high sodium content".
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?