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  #1  
Old 22nd November 2018, 12:51 PM
Keith Tapscott.'s Avatar
Keith Tapscott. Keith Tapscott. is offline
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Default Johnson's Unitol (new)

Does anyone know what the formula is for Unitol? I believe it was quite popular with amateur photographers when it was available.

https://www.photomemorabilia.co.uk/J...nchorUnitolNew
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  #2  
Old 22nd November 2018, 01:40 PM
Lostlabours Lostlabours is offline
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I used Unitol in the 1960's it contained Meritol, Johnsons never published any of their formulae.

When Johnsons closed their chemistry division Pip Pippard and some other Johnsons staff formed Photo Technology and were given the rights to use the Johnsons Scale branding.

Johnsons had also manufactured raw Photo chemicals, developing agents , B&W and colour, colour couplers, etc. They supplied other manufacturers, I have a bottle of Ilford Amidol which states it's manufactured by Johnsons.

So with no Meritol being manufactured (or Pyrocatechin) Unitol had to be re-formulated.

Ian
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Old 22nd November 2018, 05:07 PM
Richard Gould Richard Gould is offline
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Can't help with formula for Unitol, but it was the film developer I grew up with, used it in the later fifties and though the 60's, in fact I used all Johnsons chenicals and much of the equipment, it was when Unitol went that I switched to Rodinol, which I have used ever since, Unitol was a fairly forgiving developer, fine grain, and produced lovely negatives, in fact I still have some negatives developed in Unitol hidden away somewhere
Richard
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Old 22nd November 2018, 05:51 PM
John King John King is offline
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Unitol - Eee By Gum! That brings back memories. probably along the lines of ID11/D76 with a bit of a tweak here and there.

Johnson's also made Definol a high dilution and high accutance developer that went off very quickly. I never ever managed to finish a bottle of concentrate even though they were only 100cc. I always remember the concentrate had a peculiar smell as well.
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Old 5th December 2018, 01:29 PM
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Thanks, I wonder what is the nearest equivalent today. Perhaps Fotospeed FD10?
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Old 5th December 2018, 04:22 PM
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Quote:
Originally Posted by Keith Tapscott. View Post
Thanks, I wonder what is the nearest equivalent today. Perhaps Fotospeed FD10?
Unitol was designated (by Crawley I believe) as a Buffered Non-Solvent developer.

In the Film Developing Cookbook it is stated that “of well-known commercial developers, their characteristics most closely resembled by Rodinal at 1:25, but they are by no means identical”.

This section goes on to suggest that a better match would be a modified version of the standard D-165 with the Sodium Carbonate being replaced by Kodalk or by [1] adding 10-15g of Sodium Bicarbonate and [2] replacing half of the Sodium Sulfite with Sodium Bisulfite and [3] changing the Sodium Carbonate from 37.5g to 50g.

Bests,

David.
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Old 5th December 2018, 05:42 PM
Lostlabours Lostlabours is offline
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Quote:
Originally Posted by dsallen View Post
Unitol was designated (by Crawley I believe) as a Buffered Non-Solvent developer.
I don't think Crawley had anything to do with Johnsons of Hendon. Unitol came out in 1950 and Crawley's work on developers starts in the late 1950's.

In the mid 1980's I had a business lunch with two senior Ilford managers and a research chemist, they had manufactured Paterson's Crawley Developers etc, and had a few interesting tales

Ian
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Old 5th December 2018, 06:45 PM
John King John King is offline
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Quote:
Originally Posted by Lostlabours View Post
I don't think Crawley had anything to do with Johnsons of Hendon. Unitol came out in 1950 and Crawley's work on developers starts in the late 1950's.

In the mid 1980's I had a business lunch with two senior Ilford managers and a research chemist, they had manufactured Paterson's Crawley Developers etc, and had a few interesting tales

Ian
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Old 5th December 2018, 10:52 PM
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"I don't think Crawley had anything to do with Johnsons of Hendon. Unitol came out in 1950 and Crawley's work on developers starts in the late 1950's"

Crawley was definitely the person who 10000% catagorized these types of developer as 'Buffered Non-Solvent developer'.

Bests,

David.
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  #10  
Old 6th December 2018, 09:38 AM
Lostlabours Lostlabours is offline
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Quote:
Originally Posted by dsallen View Post
"I don't think Crawley had anything to do with Johnsons of Hendon. Unitol came out in 1950 and Crawley's work on developers starts in the late 1950's"

Crawley was definitely the person who 10000% catagorized these types of developer as 'Buffered Non-Solvent developer'.

Bests,

David.
www.dsallen.de
(3) Buffered, non-solvent or " chemical " developers; e.g. DK.50, D.61A, Uniyol.

A strange grouping as D61a has 90g/litre Sulphite so is a solvent type developer which isn't buffered. DK50 is derived from Wellington and Ward's Borax MQ Fine Grain developer and is buffered.

Unitol is entirely different so must be his "chemical" developer, it definitely contained Meritol, it would have had far less sulphite in a working solution than the other two. He's really making a case for diluted DK50 which came later in his articles.

Ian
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