Anyone know where to find RELIABLE Crawley FX formulas?

[steven_e007]

Is there a place where we can find genuine reliable formulas for Geoffrey Crawley's FX series?

The reason why I ask is that I went looking for FX-15 following on from an earlier thread. Googling for the formula is easy and gives plenty of hits...

So far I have found three different formulas :confused:

They all have the same ingredients - but have different values for Phenidone and Sulphite. They all make up to 1 ltr - so it isn't a proportions issue. It could be an anydrous / crystal difference with the Sulphite, but the formulas don't say which to use, which isn't helpful - but I can't see any justification for different values of phenidone?

I think it is just that at least 2 of the three must be wrong - possibly all three! :rolleyes:

Does anyone know of a source of reliable data?

Thanks.

 

[Ian Grant]

Crawley published them all in the British Journal of Photography in 1960/1, and repeated them in the PJP Almanac/Annuals until recently, a few are more recent like FX37.

The Formula for Acutol-S FX-15 was only published after it was dropped from production by Paterson, but I've seen more than one version, Crawley did modify some of his formulae over the years.

FX15 Acutol S

Metol 3.5g
Sodium Sulphite (anhyd) 100g
Phenidone 0.1g
Hydroquinone 2.25g
Sodium Metabisulphite 0.5g
Borax 2.5g
Sodium Carbonate (anhyd) 1g
Potassium Bromide 1.5g
Water to 1 litre

Hope that helps

Ian

 

[Christopher Walrath]

Wirelessly posted (BlackBerry9000/4.6.0.167 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/102 UP.Link/6.3.0.0.0)

Is that the order to mix (I assume start with 750cc water), Ian? If so I'l put it on CiM.

 

[Ian Grant]

It would be the order I'd mix it.

Ian

 

[Christopher Walrath]

Wirelessly posted (BlackBerry9000/4.6.0.167 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/102 UP.Link/6.3.0.0.0)

Thank you, Ian.

 

[jim appleyard]

A good (?) source for these might be Anchell & Troop's "Film Developing Cookbook."

 

[Lee L]

A good (?) source for these might be Anchell & Troop's "Film Developing Cookbook."

FX-15 there matches Ian's posting with one common substitution:

0.5 g of Sodium Bisulfite rather than 0.5 g Sodium Metabisulfite

Lee

 

[gainer]

According to the latest information from 1932, it would be better to dissolve the Metol first in a small amount of plain water. Metol is acid enough in this solution to prevent its own oxidation. If you add sulfite before adding the hydroquinone, any oxidized Metol will be converted to a less active sulfonate form. If the hydroquinone along with a small amount of the sulfite is added before the bulk of the sulfite, the oxidized Metol is regenerated. This advice comes from 2 redoubtable Kodak warriors, Hardy and Perrin, in their text book "Principles of Optics." It was applied there to D-76, but should apply to any MQ developer. If for some reason you would like to substitute sodium ascorbate for hydroquinone, it may be added directly to the Metol solution, as the ascorbate regenerates oxidized Metol without sulfite.

 

[Kirk Keyes]

Pat - Hardy and Perrin aside, a pinch of sulfite, added before the metol is added to the solution, will consume the small amount of oxygen dissolved in the water. (Cool water will have only about 8-10 mg/L of dissolved oxygen.) Since there is very little oxygen left in the water after the sulfite dissolves, there will be nothing there to oxidize the metol.

So which approach is better?

 

[Ian Grant]

The pinch of sulphite first does help the metol to dissolve, but then with a commercially packaged developer like D76 everything is already mixed together before you dissolve them. So it's not essential.

Ian

 

[gainer]

Pat - Hardy and Perrin aside, a pinch of sulfite, added before the metol is added to the solution, will consume the small amount of oxygen dissolved in the water. (Cool water will have only about 8-10 mg/L of dissolved oxygen.) Since there is very little oxygen left in the water after the sulfite dissolves, there will be nothing there to oxidize the metol.

So which approach is better?

The oxidation to be concerned about here is that which may have been present at the start. It is not the oxidation that might occur in solution. Granted, it might be quite small in today's product, but who knows? It is the fact (not mine, but what I read in The Theory of the Photographic Process) that whatever amount of Metol may already have oxidized before starting the preparation may be fixed as the sulfonate that I have assumed was the reason for the recommendation by Hardy & Perrin for that deviation from the usual practice of a pinch of sulfite added with the Metol. It's not really much of an inconvenience. It may be that the Q will later revive even the sulfonate. I'm just guessing that it does not . I measured the pH of the solution of Metol in water to be about 5. I will measure it again with the pinch of sulfite. I just thought it a curiosity that Hardy & Perrin used that order of mixing without explaining why, as if everyone else already should know.

 

[gainer]

PS. A small pinch of sodium ascorbate would be even better, as it restores oxidized Metol to its original form without forming the sulfonate, according to what I have read. Anyway, it might be worth considering if the Metol is very old.

 

[BradS]

PS. A small pinch of sodium ascorbate would be even better, as it restores oxidized Metol to its original form without forming the sulfonate, according to what I have read. Anyway, it might be worth considering if the Metol is very old.

Good idea! Thanks for the suggestion.

just to make sure I understand correctly, you're suggesting the following order (e.g. for D76)...
1) a pinch of ascorbate (would Ascorbic acid from the health food store also work?)
2) the metol
3) the Hydroquinone (?)
4) sulfite (or, Borax...or does it even matter at this point?)
5) borax

 

[dancqu]

0.5 g of Sodium Bisulfite rather than 0.5 g Sodium Metabisulfite
Lee

One hundred grams of sodium sulfite. One half gram of
either of the two above. Must be a misprint. Dan

 

[Ian Grant]

No it's correct. Sodium Metabisulphite is often used in small quantities in developer formulae. In theory if you use bisulphite instead you should add slightly more as it's not quite the same. I found a Kodak research article recently in a BJP Almanac (late 40's/early 50's) that compared the two and gave the suggested equivalents, the book's in the UK but I may have scanned the article. The difference is generally around 3-4% more Bisulphite is need compared to Metabisulphite.

I have 6 other film developers in my database using 0.13 up to 1 gram per litre of film developer, these are Ilford, Crawley and Agfa Ansco developers, (4 are 0.5g or less).

The importance of the metabisuphite is the free SO2 it gives off, it's often used to stabilise commercial powdered developer - used in Part A with the developing agents.

Ian

 

[gainer]

Good idea! Thanks for the suggestion.

just to make sure I understand correctly, you're suggesting the following order (e.g. for D76)...
1) a pinch of ascorbate (would Ascorbic acid from the health food store also work?)
2) the metol
3) the Hydroquinone (?)
4) sulfite (or, Borax...or does it even matter at this point?)
5) borax

1/2 level teaspoon of ascorbic acid + 1/4 tsp baking soda in a little water. Let the effervescence subside. Add this to the Metol solution. You probably dont need all the ascorbate, but I doubt it will make a noticable difference.

In fact, if you run out of hydroquinone, you can try this: multiply the required amount of hydroquinone by 1.6 to find the amount of ascorbic acid. Multiply that amount to get the required amount of baking soda. Mix these amounts in water , Use a big container,but not any more than half the water you're going to use to make the developer. It's going to fizz a lot. When it quits fizzing, dissolve the Metol, then anything else that needs to go in and enough water to bring the volume up to total. You can try this sometime when you have time to play. It will substitute about the same number of molecules of sodium ascorbate for the hydroquinone.

 

[gainer]

BIG BOO BOO!
Multiply the calculated amount of ascorbic acid BY 0.48 to get the amount of baking soda. By baking soda I mean, of course, sodium bicarbonate like you take for bellyaches such as I sometimes give people.

 

[gainer]

The pinch of sulphite first does help the metol to dissolve, but then with a commercially packaged developer like D76 everything is already mixed together before you dissolve them. So it's not essential.

Ian

I have not found any difficulty in dissolving 2 grams of Metol in 100 ml water at room temperature. If my explanation of the mixing instructions given in Hardy & Perrin is not the right one, what is? They gave none in that book, but may have in another publication.

Maybe Metol available in the 30's did have a possible oxidized component. Oxidized Metol is a development inhibitor. Sulfite converts it to the sulfonate, which at least is a weaker developing agent. Hydroquinone + sulfite regenerates oxidized Metol, as does an ascorbate. If their method is no longer needed, it still might do some good and no harm. There is no appreciable increase in time required for preparation.

 

[dancqu]

Sodium Metabisulphite is often used in small quantities
in developer formulae.
The importance of the metabisuphite is the free SO2 it gives off,
it's often used to stabilise commercial powdered developer -
used in Part A with the developing agents. Ian

SO2, sulfur dioxide, a gas. A bisulfite when moist, as it may
become with powdered commercial developers, acts like any
sulfite to preserve. Why the BIsulfite is still a mystery. Free
sulfur dioxide, sulfite or bisulfite, is unlikely because it
would take quite an acidic environment to cause it's
release. Over acidic stop baths can cause it's
release. Dan

 

[Ian Grant]

Metabisulphite is used to control the pH, the SO2 forms sulphurous acid in solution, in combination with Sulphite it also has a buffering effect.

The Sulphite/Metabisulphite buffer range is between pH 8 and pH 6.5, becoming more acidic as the proportion of Metabisulphite is increased, this is compared to the Borax/Boric Acid buffer range of pH 9.2 to pH 8.

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

 

[dancqu]

Metabisulphite is used to control the pH, the SO2 forms
sulphurous acid in solution, in combination with Sulphite
it also has a buffering effect.

That assumes some SO2 does form in an alkaline solution.
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.

The Sulphite/Metabisulphite buffer range is between pH 8
and pH 6.5, becoming more acidic as the proportion of
Metabisulphite is increased,

From one extreme to the other the ph range can be as
great 10 + to near 3. Of course not much buffering
save for up OR down at those extremes.

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

In general acidic environments do preserve better.
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

 

[Ian Grant]

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.

Ian

 

[KennyE]

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.

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Thank You

KennyE

 

[Gerald C Koch]

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.

 

[KennyE]

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.

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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.

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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.

KennyE