I have the same problem as Michael has. What is the purpose of your question? Is it merely curiousity or is there a practical reason for your question. Without more information it is hard to give an answer.
To add to what Michael said, the activity of a developing agent increases with temperature. In certain cases there are chemicals that can be added to a developer to increase its activity. These chemicals reduce the charge barrier effect. For example certain quartenary salts can reduce the induction period. Mason in his book Photographic Processing Chemistry Chapter IV discusses the mechanism of development in detail.
Do not put any metal near the grains, or no developer will ever be able to distinguish between exposed and unexposed grains! An exposed grain has maybe only a few silver atoms, you better don't mess with these and you sure don't want to put metal atoms on unexposed grains, or you might as well substitute your dev with black spray paint.I wonder if putting a metal deposit I can try to neutralize the barrier, not change the halide with a catalist, I don´t Know thanks...
You are correct. Alkalis increase the reduction potential of common dev agents, but don't make the HQ/AA stick to silver any better. A nice example for this is HQ which reduces silver halide in caustic environment, whereas Quinone is a good (albeit smelly) bleaching agent in acidic environment, i.e. you can even reverse the direction of the reaction with pH.I think this function can´t be supplied exactly with alkalies...
Can you give us any indication why you are so convinced of this? Is it just gut feeling or do you have some experimental data to support your stance?I am convinced of the qualities of hydroquinone beyond of Metol and PD, in some cases
Cobalt Hexammine and Hydrogen Peroxide are known to be heterogeneous catalysts in color development, but this is not what you are looking for.
As already explained by PhotoEngineer, this is done during coating, not during development. It's an almost 80 year old technique. Since it is already done, rest assured that there is no need to add extra. Film manufacturers generally know their trade ....I think is possible put traces of Gold, in the emulsion to sensitize it e.g,
You have experimented with iron compounds, not with metallic iron, there's a big difference. Iron compounds, depending on their concentration, membership in a complex and their oxidation state, will either develop silver halide or bleach silver. This is all described in common photographic literature.i have experimented with iron compounds (other reasons and sorry i haven´t seen the effect you have described)....
To give you some perspective: PhotoEngineer, our leading expert here on APUG, wrote a book which describes how to make and coat emulsions. It's the best and most advanced publicly available book we have on this topic. His top emulsion reaches ISO 40 with common developers. Compare this to Tri-X (ISO 400) and Delta 3200 (ISO 1200), and you see how far we are behind with our amateur means. Let's be realistic, "fattening silver" is not going to improve Tri-X.I think it could be chemicali possible to fatten the silver... with metal incorporating it into the filaments of silver with very few traces (but this is not the reason)...
That's exactly what Phenidone and Metol do. Supposedly some tertiary ammines do it as well, but to my best knowledge they are not used in commercially available developers.A catalist is possible with very few quantities to neutralize the barrier ?????
There is no hydroquinone question. This compound has been around for over hundred years and is very well understood. Developers have been formulated with hydroquinone alone. Haist's book describes its development action under high pH where it develops alone. It doesn't really do anything special.I think like explain the hydroquinone cuestion...thanks
A lot of compounds that you use in a developer has been shared, and used in a emulsion...don't you know? See Agfa APX 100 and 400 developed in the same time...As already explained by PhotoEngineer, this is done during coating, not during development. It's an almost 80 year old technique. Since it is already done, rest assured that there is no need to add extra. Film manufacturers generally know their trade ....
Catalist. I have never said i have the reason, i am only tring to understand.You have experimented with iron compounds, not with metallic iron
To give you some perspective: PhotoEngineer, our leading expert here on APUG, wrote a book which describes how to make and coat emulsions. It's the best and most advanced publicly available book we have on this topic. His top emulsion reaches ISO 40 with common developers. Compare this to Tri-X (ISO 400) and Delta 3200 (ISO 1200), and you see how far we are behind with our amateur means. Let's be realistic, "fattening silver" is not going to improve Tri-X.
the next question is the speed enhance?That's exactly what Phenidone and Metol do
David Kachel suggested a range of compounds for contracting contrast, Fe-II was not among them. Anyway, you will get some development from Fe-II but shouldn't get fogging. Your original suggestion was to deposit metal onto the silver grains, and I maintain that this will cause trouble one way or another.Catalist. I have never said i have the reason, i am only tring to understand. For example in industrial applications, certain iron compounds has been used like catalist, not metallic Iron (not heterogeneus catalist) Photographic aplication of Iron Compounds: For Example, SLIMT D. Kachel (Prebath) an Iron (II) compound, When i tried i haven´t seen black points or similar...
You still owe us the source for your obsession with Hydroquinone only developers. As mentioned before, HQ is a very well understood compound in photo chemistry. You most likely won't get a Ducati with an HQ only developer.Fatten the silver, more compact filaments if you see an enlargement with microscope, or see how is the reflection of the light, all combined with Hydroquinone like only agent developer (perhaps with little PD), is like a Harley Davidson compared to Yamaha e.g. this is noticiable with 100, 400 Iso not 25 or 50 iso...
I'd say: go for it!Another thing, if its works the catalist why don´t use it?
Actually, with the low pH of D-76, the Hydroquinone doesn't do nearly as much as you think, and Grant Haist formulated a version of D-76 completely without Hydroquinone but otherwise the same properties! If you just look for higher contrast, there already exist many published and well working recipes for high(er) contrast, no need to mess with D-76.I am sure you have developed a Tri-x 4"x5" with D-76 homemade, ok now put 11 grs. of Hydroquinone, observe the seperation and the density of higligths there is a great diference... (Hydroquinone has nothing to do? really...)
See the patent search I linked to previously. You can develop in less than 1 minute if film speed, grain and sharpness are no concern to you.the next question is the speed enhance?
because i used the PD like that patent 0,016 but i think is possible the catalist reduce the developement time 12' to
10' or 8' i do´t know.
OK is FE-III, sorry a typewriting mistake (your eagle eye) , but have you seen the mottled with black spots with SLIMT NOOOOO!!!! (if well done) you are Wrong in this point... metal is possible And sorry have you ever introduced in your formula Cd, K, Na i think....? jajajajajaDavid Kachel suggested a range of compounds for contracting contrast, Fe-II was not among them
I am not interested in this patent, i have mixed by miself this kind of developer not fully balanced yet ... but i developed 12' TMAX 100... there are compounds you use in developers or in emulsion to obtain similar results, at least with the same idea, e.g. this is agfa and the same time of develope, with film of 100, 400 etc...See the patent search I linked to previously. You can develop in less than 1 minute if film speed, grain and sharpness are no concern to you.
I have supoused and assumed that if someone answered my post should know the catalysts is not necessarily a metal could be as metallic deposit
but starting from a compound having one metal in the case of halides.
OK is FE-III, sorry a typewriting mistake (your eagle eye) , but have you seen the mottled with black spots with SLIMT NOOOOO!!!! (if well done) you are Wrong in this point... metal is possible And sorry have you ever introduced in your formula Cd, K, Na i think....? jajajajaja
Read please, I write not what you understand, this is clear...
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I am not interested in this patent
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