The patent https://patents.google.com/patent/US6350563
describes a "commercially available first developer containing Hydroquinone" for B&W reversal processing. Any idea what is the capacity of this developer? And is there a replenisher for it?
This patent is interesting already by its sheer existence. To my knowledge Agfa-Gevaert (in contrast to Orwo) never commercialized a b&w reversal processing kit, neither for consumers nor commercial users. It thus is about an modified formula for the Scala process, run worldwide back then only by a handful of commercial labs.
All I told you was I've seen this patent before and it's meant for Agfa Scala film which is no longer available. Everything else is your imagination. Anyway, Facebook messenger conversation on technical matters across language is bound to be misunderstood.
ADOX Scala Kit for B/W Slide Processing to mix 2000 ml - fotoimpex.com analogue photography
The ADOX SCALA Kit only has two parts (plus an optional clear bath), radically simplifying the black&white reversal process. Simply mix the developer and bleach 1+1 with ...www.fotoimpex.com
The patent https://patents.google.com/patent/US6350563
describes a "commercially available first developer containing Hydroquinone" for B&W reversal processing. Any idea what is the capacity of this developer? And is there a replenisher for it?
ADOX Scala Kit for B/W Slide Processing to mix 2000 ml - fotoimpex.com analogue photography
The ADOX SCALA Kit only has two parts (plus an optional clear bath), radically simplifying the black&white reversal process. Simply mix the developer and bleach 1+1 with ...www.fotoimpex.com
You stated: “Agfa Scala film which is no longer available”. The developer and the film are valiable
It states 'tank solution' - which usually means replenisher + starter. As for capacity & replenishment, you'll need to determine that in your process environment via sensitometry & the formulae in the SPSE Handbook on replenisher design.
You stated: “Agfa Scala film which is no longer available”. The developer and the film are valiable
Ok. Agfa-Gavaert first developer has relatively low amount of sulphite (11g/l) compared to other known first developers (usually >= 50g/l). I wonder if this has any adverse effect on both shelf-life of the developer as well as reuse.
Later again they bought a current film from Agfa, applied a special treatment to it and offer it under two designations, one of them is Adox Scala 50.
I'm pretty sure it's there largely as a preservative. Tank life will probably have been aimed to be inline with other similar professional-lab-oriented systems (i.e. C-41 and E-6) - and replenishment rates within a similar range. At the end of the day, Agfa's bottom line will have been that they wanted to persuade people to invest in a Scala processing machine - and that means trying to make it not seem any more difficult to run than other processes already installed. Nothing is in the developer formula unintentionally.
I'm pretty sure it's there largely as a preservative. Tank life will probably have been aimed to be inline with other similar professional-lab-oriented systems (i.e. C-41 and E-6) - and replenishment rates within a similar range. At the end of the day, Agfa's bottom line will have been that they wanted to persuade people to invest in a Scala processing machine - and that means trying to make it not seem any more difficult to run than other processes already installed. Nothing is in the developer formula unintentionally.
Thanks Lachlan. Another question. The "commercially available first developer containing Hydroquinone" in the patent has 2.0g of Nitrilotriacetic acid in it. However, the solubility numbers are a little puzzling. According to one source, solubility in water is 1.28g/l. Several other sources say it is less than 1g/l. Is the solubility of NTA higher in alkaline solution?
Mr. Raghu was quick to judge this patent when I submitted it to you, you said it was designed for specific films only, but the patent authors did not explicitly say so - they mentioned AGFA200, as an example but not limited to, ( That's what I understood), and they also didn't say that any other movie couldn't be processed using that format.
- It is completely different from the (ORWO4185) formula, which its creators said was designed only for (UN52) films, despite that, it succeeded in developing most of Ilford's products except for (HP5).
- This is a really very important patent, especially since it was issued just two years before the official closure of Agfa, and this makes it considered the last patent issued by that great company.
In general, I think that someone should take the initiative to test this formulation contained in the patent.
Why are you inquiring about a starting solution and a Replenisher solution? We are amateurs, we don't care much about that.
- Also the developer contains etidronic acid is a very powerful sequestering agent. you have to combine it with EDTA, and your developer will stay fresh much longer
By pure chance, I have an ingredient (5-methylbenzotriazole)
I think this element is a very key ingredient in that formula.
Also, I can provide (hydroxyethane-diphosphonic acid) or (etidronic acid) the same element but with another name.
I asked a supplier who specializes in laboratory chemistry, and he said it was an affordable ingredient.
- There is only one ingredient left that I still did not find because most of the chemistry companies are closed due to the blessed Eid Al-Fitr holiday, which is (polyethylene glycol,)
But I think that it is an available element, I think, I saw this name circulating on the page of the group of laboratory chemistry dealers in Egypt.
Don’t know if anyone will read this but I have formulated the agfa first developer based on the patent specifications and used it for reversal processing with very great effectiveness. I’m too tied up with work to post results right now but I will say that it works beautifully with Fomapan-R at box speed and with Ilford PanF+ at ei25-32. I’ve used it with Ilford FP4+, Delta 100 and Ilford Ortho Plus, all of which gave fair results (less dmax). Tri-x, Double x, Acros II and Fomapan 100 Classic were all relative failures with poor thin image quality and/or excessive fogging. Films with more inherent emulsion contrast seem to do very well with reversal development. First development times must be customized to each film (Fomapan-R takes 12 min@70F while Ilford PanF takes 18 min@70F). The process I use has a light reversal rather than chemical and uses chromium bleach. The hardest material to source was the hydroquinone sulfonic acid sodium (or potassium) salt. I am currently tinkering with the ingredients to come up with a replenisher so I don’t have to toss the original developer. Will send more at some future point.
Interesting, hydroquinone sulfonic acid sodium (or potassium) salt is in some Moersch developers (film and paper) that appear to have some desirable characteristics (the potassium salt in these cases).
Does anyone know anything more about it? Should we be trying to source some of it?
Don’t know if anyone will read this but I have formulated the agfa first developer based on the patent specifications and used it for reversal processing with very great effectiveness. I’m too tied up with work to post results right now but I will say that it works beautifully with Fomapan-R at box speed and with Ilford PanF+ at ei25-32. I’ve used it with Ilford FP4+, Delta 100 and Ilford Ortho Plus, all of which gave fair results (less dmax). Tri-x, Double x, Acros II and Fomapan 100 Classic were all relative failures with poor thin image quality and/or excessive fogging. Films with more inherent emulsion contrast seem to do very well with reversal development. First development times must be customized to each film (Fomapan-R takes 12 min@70F while Ilford PanF takes 18 min@70F). The process I use has a light reversal rather than chemical and uses chromium bleach. The hardest material to source was the hydroquinone sulfonic acid sodium (or potassium) salt. I am currently tinkering with the ingredients to come up with a replenisher so I don’t have to toss the original developer. Will send more at some future point.
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