Another chemical mud pie noted:
A moderately buffered solution was made to try to avoid the pH drop problem.

Solution A (this is to hydrolyse Paracetamol/Tylenol to the developing agent sodium aminophenolate.)10% more sodium hydroxide than theoretically needed was used.
Content of 16 Paracetamol capsules....................8g
Sodium Hydroxide......................................... ..4.64g
Water to................................................ .......100 ml
Leave in a full sealed bottle for 1 week at room temperature for the hydrolysis to complete.

LS-1b1
Ascorbic acid.............................................. ......10g
Solution A above............................................. ..50ml
Sodium Bicarbonate....................................... ....10g
Sodium Carbonate Decahydrate...........................10g
Water to................................................ ............1L
Develop for 1.5x Xtol 1+3 times.It worked at first.

However this buffer did not stop the pH drop problem, initial pH of 9.0 fell to 8.8 after 7 days,7.8@14 days, 7.7 @23 days.
I am now trying a more strongly buffered solution, 50g/L Sodium Carbonate anh equivalent.

Note sodium hydroxide is caustic, hazardous:
http://www.ccohs.ca/oshanswers/chemi...hydroxide.html