New to hobby.

[Klrdds]

Yes blue ink is preferable. I have used for 40 years a plain Bic blue ballpoint medium tip pen with the plastic cap , no gel ink , and I have had no trouble with that . I never touch the sweet spot with my fingers and I try to wipe the ball down with the enclosed paper or a paper towel before getting the baseball signed.
Storage and display are the biggest concerns however.

[MrSeven]

Something else I've be wanting to do is to buy ROMLBs in advance (year or two) and watch to see if any of them start to turn yellow/blotchy due to manufacturing and discard those for autographs.

[mr2686]

Originally Posted by MrSeven

Something else I've be wanting to do is to buy ROMLBs in advance (year or two) and watch to see if any of them start to turn yellow/blotchy due to manufacturing and discard those for autographs.

I used to buy balls by the case, and there were times I didn't use a few for a couple of years...never had any problems with discoloration or blotches, but most of that comes from either sunlight or oils from the hands that are handling the baseballs.
As for what pen to use, I too prefer the Bic med point blue.