I didn't realize I hadn't posted about this until I saw the thread that Pensacola Tiger started about the petty he got from me.
One of the things I have noticed about all the damascus knives I have seen other than my own are etched very shallowly. I etch my blades a little more deeply to provide a bit of texture in the steel as well as durability to that patterning as well. All sharpness on the surface of the steel as a result of the etching is polished down in my process. You can think of the etch as a patina, as well as having some topography.
When I did my first kitchen knife I thought about this for quite a while. I realized that the surface of the blade may be able to harbor small food particles and as a result bacteria if I did not do something to prevent it. I wanted something food safe but also something that would last.
My answer is as a final step to heat the blade after it is etched and cleaned and apply beeswax to it, and while the wax is still molten wipe off any excess. This wax will seal off any of the samll spaces that food might hide and provide a protective finish for the majority of the blade. It will also greatly diminish the reactivity of the blade. You should be able to cut any of the normally reactive foods, such as lemons and tomatoes without any taste or color change on the food at all. Neither should the blade change color, except at the edge.
Another benefit is that although a soft wax it is very durable. I have been using my personal knife since september of 2010 and there is still no reactivity and no color change in the blade at all. It can be removed, but I advise against it, it was put there on purpose.