To the first part of this discussion, 1+0 means using the stock solution; 1+1 means 1 part stock, 1 part water.(posted 8199 days ago)In regards to ID-11 vs. D-76, the published formulas are identical, but neither Kodak nor ILFORD produces a product exactly like the published formual. Both commercial products have additional buffers and preservatives. In some films, they will produce slightly different results. Sometimes, the differences are enough that ILFORD ends up with different recommendations for the two developers, but because of rounding, the difference may not be as much as it appears.
In practical applications, it is safe to use the published time for ID-11 with D-76, and vice versa. If you are doing precise work, you will need to pick one developer and stick with it.
David Carper ILFORD Technical Service