Quote Originally Posted by Tom Stanworth View Post
I think I will just try to develop at 20 degs C every time, or at least darned cloe LOL! This is waaaay too complicated for me.

I am quite partial to Xtol mixed with rodinal at the moment so I dont suppose I am going to find any published figures for that! I know some love to be super accurate, but I have found a bit extra here, or a touch too little there has no real impact on my ability to make a really satisfying print. still, it is nice to be able to get things right, consistent etc.

A simple question (I hope): By compensating by +/- 10% for every degree either side of 20, is this too much or too little compensation for most developers?
Looks about average to me. Measure the pH, and if it falls in the range of the graph I sent, use the k that you read from it to calculate the development time at 10 degrees higher or lower. One of the lines on the graph that PE sent should have about the same change in time for 10 degrees. Shift the time scale of the chart so that your favorite developing time is where the line through 20 C crosses the time scale. You could make a sliding time scale so you could use the chart like a slide rule. If you do this, let us know.