Phenidone for Hydroquinone

[patrickjames]

I was interested in mixing DK-93 but want to use phenidone in place of hydroquinone (or use asorbic acid or sodium ascorbate). What would be the relative amount of the substitution. It does not have to be perfect, I am looking for a ballpark figure here. 2.5g of hyfroquinone = what amount of phenidone or asorbic acid?

Patrick

 

[Ian Grant]

You can't replace Hydroquinone with Phenidone, but I guess you can try using Ascorbic acid. Why not try a ballpark figure of 1=1 as a starter then raise the Ascorbic level and see if that improves the developer.

Ian

 

[Tom Hoskinson]

I was interested in mixing DK-93 but want to use phenidone in place of hydroquinone (or use asorbic acid or sodium ascorbate). What would be the relative amount of the substitution. It does not have to be perfect, I am looking for a ballpark figure here. 2.5g of hyfroquinone = what amount of phenidone or asorbic acid?

Patrick

The Kodak DK-93 recipe calls for both Kodelon and Hydroquinone.

(there was a url link here which no longer exists)

Patrick, did you intend to replace both the Kodelon and Hydroquinone? If so, a combination of ascorbic acid and p-aminophenol might work ok - -.

A combination of metol and ascorbic acid should work well (see Pat Gainer's recent posts on this subject).

 

[Ian Grant]

The published formula for DK-93 I have in a UK publication uses Para-aminophenol Hydrochloride, not Kodelon.

Perhap the attached link will correct a few misconceptions, Kodelon is Para-aminophenol Hydrochloride !

Kodelon

Kodelon is purely a an Eastman trade name for the hydrochloride form of Para-aminophenol.

Ian

 

[srs5694]

It's probably better to try sodium ascorbate rather than ascorbic acid, since the ascorbic acid will throw off the pH of the developer. You could compensate, of course, but that'll add more complications to your experiment. Anchell suggests (in The Darkroom Cookbook) using 1.8 times as much sodium ascorbate as hydroquinone when making this substitution.

If you've got ascorbic acid and sodium bicarbonate (baking soda) but not sodium ascorbate, you can make a solution equivalent to a solution holding 100g of the latter by combining 89.0g of ascorbic acid with 42.4g of sodium bicarbonate in some water. It'll fizz; wait for that to subside. You can, of course, scale these amounts as required for your formula.

 

[patrickjames]

The Kodak DK-93 recipe calls for both Kodelon and Hydroquinone.

(there was a url link here which no longer exists)

Patrick, did you intend to replace both the Kodelon and Hydroquinone? If so, a combination of ascorbic acid and p-aminophenol might work ok - -.

A combination of metol and ascorbic acid should work well (see Pat Gainer's recent posts on this subject).

Tom- Your formula is the one I was interested in. I would like to keep the p-aminophenol but wanted to replace hydroquinone with either phenidone or AA. I was looking for a warm tone developer.


Patrick

 

[Tom Hoskinson]

The published formula for DK-93 I have in a UK publication uses Para-aminophenol Hydrochloride, not Kodelon.

Perhap the attached link will correct a few misconceptions, Kodelon is Para-aminophenol Hydrochloride !

Kodelon

Kodelon is purely a an Eastman trade name for the hydrochloride form of Para-aminophenol.

Ian

Ian:

Elementary Photographic Chemistry, Eastman Kodak Company, Rochester, N.Y., 1928: States on Page 18: "Para-AMINOPHENOL OXALATE is manufactured and sold by the Eastman Kodak Company under the name of Kodelon."


Gerald Koch argued that p-aminophenol hemioxalate would be a more chemically correct name.

In any case, my tests indicate that either p-aminophenol Base or p-aminophenol HCL may be substituted for Kodelon in the DK-93 formula weight for weight.

 

[gainer]

It's probably better to try sodium ascorbate rather than ascorbic acid, since the ascorbic acid will throw off the pH of the developer. You could compensate, of course, but that'll add more complications to your experiment. Anchell suggests (in The Darkroom Cookbook) using 1.8 times as much sodium ascorbate as hydroquinone when making this substitution.

If you've got ascorbic acid and sodium bicarbonate (baking soda) but not sodium ascorbate, you can make a solution equivalent to a solution holding 100g of the latter by combining 89.0g of ascorbic acid with 42.4g of sodium bicarbonate in some water. It'll fizz; wait for that to subside. You can, of course, scale these amounts as required for your formula.

The easiest way to get sodium ascorbate from ascorbic acid and baking soda is to use 2 teaspoons of ascorbic acid and 1 teaspoon of baking soda for each 10 grams of sodium ascorbate. It's close enough for practical use.