Hmmm.. I too have some ash (some of it olive) that needs finishing, on a set of shelves, and my preference would be for something that affects the colour of the wood as little as possible.
I find that whenever I read a thread here that answers my questions, I come away slightly more knowledgeable and much more confused!
I have read (in a Charlesworth book) that using shellac makes a good seal. Can shellac be used on ash? And would several coats be enough on its own? And if I go down the shellac route, will I end up by giving the shelves a final polish under the wheels of a large tractor before heading off to Ikea in high dudgeon?
It seems from reading this thread that the Rustins stuff will yellow slightly with age unless the wood is sealed first. Is that right?
The shelves are for cookery books, so will see quite a bit of traffic.