Toughness is going to be determined by the steel alloys used in the Damascus mix and the degree of heat treating knowledge of the maker.
Ideally, the two or three steels used should be of similar carbon %. The display of the pattern created is done so by etching in acid and how the acid reacts to the nickel content of one of the steels.
The "fineness" or layer count will assist in the equalizing of the carbon content through migration, if there is a differing C% in the steels used.
This may effect the cutting edge if there is not a sufficient # of layers and/or time at welding heat to facilitate said migration.
And here's a "rule" I learned long ago about "cutting" ability of steels:
"Geometry cuts - heat treatment and alloy determine how long."
And, "If Jesus Christ sent a bar of steel down from Heaven, it will only be as good as the heat treatment it gets."
Damascus is not one bit better than the alloys used.
Bottom line is that Damascus in and of itself determines little to nothing. It's the maker's ability to understand his alloys and heat treatment practices from the time he makes his first forge weld of the billet until the final tempering after hardening and the resultant geometry of the edge.
There are no cut and dried rules to blade performance.
Know the maker first. Find one that knows what he's doing.
Do not judge today's pattern welded steel to yesteryear's Damascus barrels. There's no comparison possible.
That's like trying to compare a Model T to a Mustang GT.
The pattern is often determined by the length of time etched, and the post-etching processes of the maker to lock in the oxides. Personally, I hot blue my Damascus and it stays that way an incredibly long, long time - just like a gun barrel.
The variables in modern Damascus are as many numbered as there are makers who make it.
Good questions.
