Quote Originally Posted by Rudeofus View Post
Paul, Phenidone is known to be unstable in alkaline environment so your ID-67 formula would be quite unsuitable for long shelf life. Replace the Phenidone with twice the amount of Dimezone S if you want longer shelf life.
I rather doubt that phenidone is unstable in the alkaline developer environment. Maybe less stable than Dimezone, but not unstable. I rather doubt Ilford and other companies would have spent years making and marketing phenidone/HQ developers if this matter was of concern. Nor has this been any kind of problem in my own mixes and use.