I recently switched to d23 and found it hard to find development data compared to d76. I actually went to the MDC and made a spreadsheet comparing average ratio of d23 times to d76 times so I would have some idea where to start on films like Acros that have no data available (I found that about 75% of the d76 1+1 time was average for a d23 time). Even Kodak datasheets don't give d23 times. I don't mean to call out Photo engineer specifically but I've never heard of such a test. How is it conducted?