Let me start by saying I am not a scientist. I have been collecting for decades, in that time I have purchased autographs, done TTM requests, traveled to conventions, and hit the streets in search of every possible signature that I wanted. I consider myself to be pretty successful at this hobby, and for years my answer to one question has been the same.
What's the best pen to use for an autograph? For 2 decades my answer has been a blue permanent overhead transparency marker called Vis-A-Vis by the Sanford Company, the same company that makes Sharpie brand markers. The problem is that the Sanford company discontinued the Vis-A-Vis permanent blue marker about 10 years ago. Sure you can find some "new" old stock here and there, but the prices can get pretty crazy.
Yes, I have a box or two in reserve for those events, special enough to get me out of my comfy chair, but that isn't going to help me in telling people that the best option for them doesn't exist anymore. So I decided to do a little experiment. Did the results shock me? Absolutely, but I should add that I have been out of wall space for 10+ years. My collection now is mostly all stored away, and my answer remains the same. It is still 100% Blue Vis-A-Vis for me, but there is a really good possibility that it shouldn't be for you.
I grabbed an acid free white cardboard backer-board, the type you will find sealed away behind a comicbook or magazine in a polybag, then I grabbed some brand new Sharpies, Vis-A-Vis, paint pens, a ballpoint, and even a dry-erase marker, in a variety of colors.
Next, I used each pen and initialed the board repeatedly in four columns. One column for the baseline, the second for display under filtered fluorescent overhead light, column three was for display in a sunlit room (through modern UV protective window,) and of course column four for display near a regular 60 watt incandescent lamp.
Here are the results.......
10 days of exposure
So, the way I see it is if you plan on displaying your signed items in any light source at all, blue Vis-A-Vis may not be for you. Black Vis or black sharpie may be the way to go if you are collecting in the streets, if you are at a show, you may consider one of the paint pens,(just be sure togive it time enough to dry, before storing it in yor bag or poster tube.)
I still believe that blue is the way to go for me because of how wonderfully it pops on both color and b&w images. It's just not the best for long term display in a well lighted area.
I really hope this helps some of you, and I hope you and your families have a safe and happy holiday season.