[Malcolm Swan]

Do you mean 1:4 from the original concentrate? If so, why not just use 1:7 dilution and do two separate batches of five and four. You'll end up using about the same amount of developer, and the smaller batches will be a lot less awkward to handle during the processing. What kind of film is involved? I routinely use 1:7 for T-100 and T-400; glad to supply my typical times if you want.

Konical

Yes, I use 1:4 from the original concentrate. The 7 films in the tank were Tmax 400, but the other 2 were HP5 plus, which I did separately.

I develop the T-Max 400 in 1:4 T-Max dev for 9 mins at 20.5C, which gives me quite dense negs, but thats the way I like them. I'd never developed HP5 in T-max before. The recommended time was 6 1/2 mins at 20C, so I gave them 7 mins at 20C and they look OK altho not as much contrast as I like. However I haven't printed them yet. Yes I'd appreciate seeing your times for 1:7 if not too much bother!