That assumes some SO2 does form in an alkaline solution.
Metabisulphite is used to control the pH, the SO2 forms
sulphurous acid in solution, in combination with Sulphite
it also has a buffering effect.
We are dealing with the alkaline developer FX-15. SO2 will
form if the solution is acidic; first sulfurous acid then as the
solution becomes more acidic, free sulfur dioxide.
From one extreme to the other the ph range can be as
The Sulphite/Metabisulphite buffer range is between pH 8
and pH 6.5, becoming more acidic as the proportion of
Metabisulphite is increased,
great 10 + to near 3. Of course not much buffering
save for up OR down at those extremes.
In general acidic environments do preserve better.
As a preservative Metabisulphite is many times more
effective than Sulphite., which is why it's used in the
food trade and wine making. Ian
Patrick Dignan recommends dissolving phenidone in
a bisulfite solution.
FX-15 is a long way from being acidic. That ONE
HUNDRED grams of sulfite swamps any ph effect by
the ONE HALF gram of bisulfite, or for that matter,
the ONE gram of carbonate.
I'm quite sure the latter two could be left out and
nobody would notice the difference. Dan
So you're saying that Crawley and the chemists at Agfa, Kodak & Ilford etc don't know what they are doing when they put such small quantities of Metabisulphite etc in a developer
Paterson/Crawley put less in one of their other developers, sometimes small quantities have disproportionally beneficial effects.
Acutol-S / FX-15 isn't a normal fine grain film developer, it was formulated specifically to give high acutance which it gives at the expense of a slight increase in grain and loss of tonality. It's no co-incidence that the other developers using these small quantities all give additional acutance.
Take the Metabisulphite & the Carbonate out and you'll have a developer with quite different attributes.
Crawley's FX series formula FX-26 universal developer
I am new to your forum. I have not truly posted yet because I am writing and putting together a research paper for this forum, as part of my first post and coming aboard arrival.
Yet I have run into a small problem and I require some assistance after weeks and months of research. I need and require the formulas for Crawley's/Paterson's FX-26 Universal developer and Johnsons of Hendon Universol Developer.
If anyone can assist me, it would aid me in completing this research paper by Mothers Day, May 12, 2013. And I will post it online in both .doc and pdf formats. Allowing others to add, edit, and post their own information to it. It is truly a remarkable research paper. I just require a little amount of assistance.
I truly believe that somewhere out there, some one has the information that I desire, and can add their valuable infor to the research paper. It is my belief that once this research paper is posted. Hundreds of thousands of people will download it, add to it, and keep it growing, until it will develop into one of the most sought after pieces of document the world have ever known. And all of you, can be a part of it.
Most commercial developers are jealously guarded trade secrets. You are not going to find the actual formulas published. What you may find is what one person thinks the formula might be.
A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.
~Antoine de Saint-Exupery
Anyone know where to find RELIABLE Crawley FX formulas?
Yes..., that is a true statement. But I do need something to start with. I deeply feel and believe that someone knows or have those formulas that I seek.
I sit here and I think back to 1999, remembering the times as we moved closer towards Y2K, hoping for change towards a better world. And all I got was September 11, 2001.
What I have learned from that time is that only we the "people" can make that better world. One thing at a time, one improvement a day or week, or month.
We as humans, left so much of our knowledge behind, from the last century. Not mention the other centuries before that. We go through life thinking the other guy will take care of it.
Well, I am that other guy. I am tired of leaving our hard earn knowledge behind, allowing it to go waste. I am tired of saying "do you remember when", " do you remember that or this". We need a place to go to, to replenish our knowledge, thoughts, and dreams.
No one on this planet owns anything. We are all borrowers. Because when God calls for our attention. We must go. And all those things we claim to own. Does not leave with us. We own only one thing. Our knowledge. Because when we pass, that is the only thing that we take with us. Our souls.
I want to leave things behind for those that come after us. So that they see and draw knowledge from the past and maybe incorporate it for use in their future.
We as a people, can not allow this information to die. For I remember the great and powerful automotive companies of the past, Tucker, Rambler, Hudson, Packard, Oldsmobile, Plymouth, Saturn, Pontiac. All their technical knowledge is nearly lost. Only a select few has access to it. But when they die, then what.
Will their heirs safe guard it or merely trash it, as so many others have done.
Yes, I am a romantic, but I want the stream of knowledge to flow to the masses..., forever.
So I say to you all..., stop the B.S., get me the information; so that I can share it with the world.
It is out there. Please release it.
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