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.
Originally Posted by BradS
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.