ascorbic acid as a substitute for metol and hydroquinone

[Tronds]

I have about 300g total from two sources (two separate jars). One slightly less than 250g, another around 60g. If you're serious please email me directly.

I have sent you a PM earlier, but got no answer.
Reading the comment you wrote in another thread, I think I just drop this. I don't want to do any business with you.

Metol is sold other places so I have no problem getting it.

[RalphLambrecht]

The similarity between hydroquinone and ascorbic acid is only superficial. Their actions in developers is quit different. Any MQ or PQ developer must be modified when substituting ascorbic acid or sodium ascorbate.

gerald, i think you and michael are quite right that a sustitution is not as simple as i had hoped. so far, from what i'vr read, i conclude a starting point is :replace metol wiyh 1%of its weight with phenidoneand replace hydroqinone with 8/5 of its eight with sscorbic acid. i wil try this with d76 first(i think it's called e76),and report the otcome.thamks for the commrntts so far.

[piu58]

> :replace metol wiyh 1%of its weight with phenidoneand replace hydroqinone with 8/5 of its eight ...

Dear Ralph,

please note that such developers have some disadvantages against the older formulae. Phenidone is very active and need to be in solution in a very small amount. Therefore it is not able to develop a film by itself, the amount is to low. The redox system is strongly necessary. (In copmparision: Metol alone will develop you film, even if the HQ is nearly dead).

The small amount of Phenidone will not lead to any discoloration of oxydized developer. Citrix acid's products are colorless too.

This leads to:
- You don't see if the developer is aged, no brownish color.
- Because of the high activity of Phenidone the developer will work with the smallest amount of the redox system (citrate). Some days later, when this small amount is exhausted, the developer will not develop anymore. The amount of Phenidione is to small for a "slow dying".

[Athiril]

Ascorbates will regenerate phenidone, you can have a pH where ascorbate won't develop, but with phenidone regenerating it'll again be more active than without it.

[RalphLambrecht]

athirl,

do you have a working formula, you can recommend?

[Michael R 1974]

XTOL? Although apparently the jury is out on whether the ascorbic acid is the primary developing agent or secondary agent in XTOL. On the surface of things one would expect it to be the secondary agent particularly at XTOL's pH, but notably one of XTOL's primary formulators (Zawadski) believed ascorbic was the primary developing agent. There is a reference to this in Anchell/Troop.

[RalphLambrecht]

i decided to try the e76 formula from Chris patten.

[Bruce Osgood]

If it's not going too far off topic, I can offer a formula for MYTOL, a Phil Lewis act-alike to Xtol. This is from Jack's Spec's site, when there was a Jack's Specs site.


Sodium Sulfite................60.00 g
Sodium Metaborate...........4.00 g
Sodium Ascorbic..............12.00 g
Phenodine........................0.15 g
Sodium Metabiosulfite.......3.00 g

I don't think I've ever tried it.

[Gerald C Koch]

i decided to try the e76 formula from Chris patten.

I would not recommend E-76. It is a perfect example of a formula where little consideration of the unique properties of ascorbic acid has been made. I would suggest either the Xtol formula or DS-10 both of which are on APUG. I have used both and they are very good.

[RalphLambrecht]

ds10 is my 2nd choice. mytol is my 3rd.