There's nothing particularly fussy about HC-110; it was marketed for its consistency. And if your development times are too short, you're either using too strong a concentration or too high a temp. I don't know how one could be 30 sec off with any developer; that sounds careless. Perhaps you are mixing it incorrectly.
Well, Drew, while it's true that I didn't exactly pass my high-school math classes with flying colours, I do know how to mix 1+31
.
Now if you took the time to read the Adox HC-110 label, you'd have realized that they acknowledge the fact I noted, by stating "High dilutions for contrast control possible!".
At dilution B, HC-110
is fussy, and, when the manufacturer suggests development times as "Aprox. 5-6 minutes," well, then it is quite possible to be 30 seconds off without being careless.
Would the suggestion provided by Covington Innovations, which Matt mentioned, solve the "critical" nature of the short times in the case of some films, namely by moving to higher dilution?
As I just mentioned, Adox does suggest moving to higher dilutions to better control contrast.
I didn't have much time to work with it this weekend, so just went for 1+31 with FP4+ and Delta 100, and Bruce Barnbaum's 1+33 dilution with HP5+.
For Delta 100, I went for 6 minutes, Ilford's suggested time for HC-110, and the upper limit time suggested by Adox for 100 ASA films. The negative is clearly over-developed, and I'm sure shaving off 30 seconds will make a big difference.