I've tried a number of pens to sign prints. If black is the color you want, I have found the Staedtler® Pigment Liner Sketch Pens to be awesome. You can buy a set of 4 pens which feature black, acid-free ink, 4 line widths (0.1, 0.3, 0.5, 0.7) and indelible, lightfast and waterproof ink. 4-pens set will cost $20.99.
If I want silver, gold or white pigment inks, I use Faber-Castell® PITT® Bullet Tip Artist Pen, $4.49 each.
Regards,
Bud James
Please check out my fine art and travel photography at
www.budjames.photography or on Instagram at
www.instagram.com/budjamesphoto.