I recently mixed a batch of Pyrocat-HD and now that I have used almost all of my Neopan400 I tried the new batch of Pyrocat-HD with HP5+ which I'll probably settle on from now on. The test roll was disappointing, being quite low in contrast and the speed was not as good as my Neopan400. To cut a long story short, I suspected my part_B. I bought a large bag of potassium carbonate some years ago. Stored it in plastic bags inside plastic kitchen canisters, not perfect storage but probably good enough (maybe not?)
I tested the density of my Part_B and found it to be about 1.439. I used the data on the engineering toolbox web site to calculate that the Part_B should have a density of about 1.532. Using the same data, I concluded that my Part_B is only about 597g/L instead of 750g/L. Now I use more (x1.26) which is helping.
I measured correctly in making it up in the first place. Could my potassium carbonate have absorbed that much water from the atmosphere? It doesn't look lumpy.