It's been said above that it should be polished then oiled.
Here is a damascus pen a made a while ago.
The first pic is of it 'polished' which as you can see, hides the damascus pattern. The second pic is after I soaked it in ethanoic acid ( vinegar ) to bring out the grain. I do use it now and then ( on my desk at home ) and have found that just handling it, stops it from rusting.
If it was oiled before pickling then it probably wouldn't have a pattern
Skiprat; What a difference !!! If you had not stated what you did to inhance the grain, I would have taken the first photo as chrome, stainless, or aluminum. The folding of damascus realy gives it a super look. As for the rusting, I have Japaneese irons in some of my antique hand planes that are hundreds of years old that are damascus steel. They turn a dark gray or black, but I have never seen rust on any of them. My guess would be that the makers quenched them in oil as they worked the metal, and retained some of that oil in the metal itself. Allot of the plane irons and swords were forged out of old boat anchor chains that had been in the elements for a number of years with no rust. The color in Roy's pen, is what my plane oron look like after 200 years. I have never reoiled my irons or sword blades. Jim S