Look, I just put that last part in there in case Bruce wanted to know how a TRUE ratio was figured.Originally Posted bydancqu

If we all just replace the colon in a dilution with a plus it will save a lot of head scratching. Remember that first of all.

When Kodak says "D76 1:1" they mean one part D76 and one part water. I don't know why they use the ratio thing here (the colon) instead of a plus sign. It's been used for a long time though, and they probably won't change it. I'm sure the chemists who work for Kodak know the difference between a ratio (expressed with a colon) and additive notation (expressed with a plus sign). We want additive notation to make things easier, and, so things like a ratio of 1:1 don't cause so much misunderstanding.

The definition of a ratio is: "The relation of two quantities of the same kind." So, the ratio of:

1:0 is a misnomer. You can't have a ratio with only one quantity

1:1 is what we call stock solution. One part developer in atotalof one part. That's a 100% solution.

1:2 is half stock and half water.... and so on.

There are three ways to express a ratio, and maybe this will help clear things up: 1:1 or 1/1 (like a fraction) or 1 divided by 1. If you use the fraction method you will see that a 1:1 ratio is 1 or for our purposes, stock solution.

Again, Kodak uses the colon to denote an additive notation, while Ilford and Agfa (and others) use the more conventionalplussign.

Just remember to replace the colon with a plus sign and all this ratio stuff won't matter.