Most staining formulas would be examples of this. The alkali is always a separate concentrate. So I would say pH does matter if the developing agent becomes particularly unstable at the working pH and the amount of preservative is low. This is typical of staining and high acutance formulas that rely on relatively low concentrations of developing agent and sulfite at relatively high working pH values.
In support of my previous statement, pyrogallol plus sodium hydroxide is used routinely in the sciences to scavenge oxygen from closed systems. If there is very little oxygen present there is little color change indicating decomposition. So in the absence of oxygen even this very unstable mixture is stable. I have vials of Neofin Blue that are decades old. They are still colorless since no oxygen can get in. Yet break the seal and the developer is quickly spoiled. So the danger to developers is not their alkalinity but exposure to oxygen. For most developers, which I assume the poster is talking about, leaving the alkali out makes little difference. As Michael pointed out certain special developers are an exception unless one does something similar to what Tetenal does.
Quite true. What I should have clarified in my post was that in the end even for the developers I listed it is still oxidation at work rather than pH per se.
What makes me wonder about seperating the developer is that I read somewhere D-76H doea not last long, somewhere else I read it does last long?? The Willi Beutler formula has the carbonate seperate for example. I was just wondering on the line of usually it shouldn't be a bad thing.
Sure the developer should be in a closed bottle etc etc but then again...just wondering.
what is the question?
The question is if I mix a developer and seperate the alkali/accelerater from the rest will its shelf life increase. Mixing the solution shortly before use.
Andreas - re-read Gerald Koch's answer above.
We should also clarify what you mean by D-76H. Typically D-76H refers to the "Haist" version which omits the Hydroquinone and increases the Metol to 2.5g/liter. But there is also D-76h which is a buffered version of D-76.