[nechesh]

Welcome to the forum Pusaka.I would concur with Rick and would add a few more items. Firstly, as in the past with old keris, there are all levels of quality to be found in new keris. I have seen new keris which are at the highest level of keris making both technologically and artistically. Of course they cost more than a couple of hundred dollars.
The iron in certain old blades is prized for it's quality. However, i am unaware of there being "black" iron. All keris that have the pamor pattern raised with the iron black get that way through a staining process which uses arsernic to stain the iron black while leaving the nickelous pamor material silvery or gray. Traditionally this was a process which was done on a yearly basis yielding the results you see in Ricks example.
As Rick points out, you should NEVER sharpen a keris blade unless your aim is to ruin it.You will find that many are sharp in varying degrees, but the keris is essentially a stabbing weapon. I suppose the majority of new blades aren't made sharp because they are no longer intented to act as a weapon. But i am sure that many of the higher quality new blades would hold an edge just fine if they have one.
You will find that there are VERY few actual empus left in Indonesia. There are many talented smiths. Commissioning a blade from someone like empu Djeno (even he only supervises as his apprentices do the work) would be a fairly pricey affair and would probably take a couple of years at least. Sometime new blades are made from melting down out blades, but i am not sure this would give you a higher quality product in the end.