Hi Jeff,
If I already have each image filter with saturation set to -15, if I add a print filter with saturation set to -10, will it be additive, and cause the saturation to be -25?
I don't think it would be additive. The range goes from -100 to +100 so I would assume -15 is like 85% of maximum and an additional filter of -10 would be like 90% of the first setting so you would end up with ~77% of the original saturation. But I'm just guessing really
I sure wish the Fill Light filter didn't change the saturation, or at least didn't change it so drastically. It seems to me that it more than compensates for the decrease in saturation you would see when adding brightness. Maybe you don't ever underexpose your images enough to see what I'm talking about, but a Fill of 10 or more really ruins the photo, and requires reducing the saturation a lot.
I regularly expose for highlights and find that Fill of 15 and above increases saturation too much. In fact in a recent post (I can't find it though) Mike said something using Fill up to 15 before Saturation is affected so hopefully he will tweak his Fill algorithm in the near future.
Terry
Edit: I found Mike's reference to Fill and saturation:
http://ddisoftware.com/tech/general-tech-discussion/not-convinced-raw-vs-jpg/msg7158/#msg7158Reply #24