Yeah, I'm eating a little crow right now. I should be more careful on forums like these.
Ink tests don't seem to be as reliable when authenticating documents since there seems to be a lot of disagreement among researchers. The parchment material seems to be the best thing to hang your hat on.
After doing a little refresher reading I'm willing to concede that the map is probably authentic. But there are inaccuracies in the map that would correspond to the limited knowledge of the western hemisphere at the time the map was assembled. It's an amazing map, just not as amazing as some of the UFO-crowd would have you believe.
I've learned to take anything that Walter C. McCrone had to say with a lot of salt... say, about about 100LBS. McCrone's claim to fame has been his "debunking" of the Vinland Map, his declaration of the Shroud of Turin as a "beautiful painting," and the exposing of the HItler Diaries. I believe that only the last stands up to scrutiny.
McCrone did claim that the Piri Re'is Map is a fraud... but did not publish any papers on the subject. Anatase was again the reason for his claim... ignoring the fact that anatase was only started to be used in modern inks in the mid 1930s... but the map had a known provenance of 1929 when it was found in a chest in the Palace of Topkapi, Turkey.