In the "official" recipe for D76 the hydroquinone <SP?> isn't active and only the metol actually does the development. This is a result of the PH being to low. However after D76 is mixed the hydroquinone <SP?> reacts with the Sodium Sulphite and causes an increase in PH which is enough to make the hydroquinone active causing an increase in development. Unless you plan on using the D76 in a replenishment line it's best to simply eliminate the hydroquinone and increase the metol to 2.5gm per liter of stock.
It won't help with the drop off in activity over time resulting in oxidation but I mix it one liter at a time so that's never an issue for me.
Originally Posted by Frank Pittel
In the "official" recipe for D76 the hydroquinone <SP?> isn't active and only the metol actually does the development. This is a result of the PH being to low. However after D76 is mixed the hydroquinone <SP?> reacts with the Sodium Sulphite and causes an increase in PH which is enough to make the hydroquinone active causing an increase in development. Unless you plan on using the D76 in a replenishment line it's best to simply eliminate the hydroquinone and increase the metol to 2.5gm per liter of stock.
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