My experience relates to HP5+ and D400, but I also noticed, when I tried 1:2 dilution over 1:1 dilution, that the grain was more apparent. Supposedly, this has to do with a smaller amount of sodium sulfite at the higher dilutions. The negative looks sharper but the grain is more pronounced. To "combat" this, I started to use less agitation. I agitate continuously for first 30 seconds, and then only do 2 inversions every minute. It seems to help. If you still don't like the grain, go to 1:1 dilution.(posted 9151 days ago)Hope this helps.