What kind of ink to use for finger print guest book?

This is the kind that is the most popular. You can get them at Michael's or Joann's for $10. They come in a set of 4.

I would also suggest having baby or alcohol wipes instead of tissues.

I second the baby/alcahol wipes. My wife's cousin did this at her wedding (see attached image) and they had those wipes and the ink was still on fingers (made for some great photos!)

Oh neat! Did she get the wet-wipes personalized?

We are doing a finger print tree as well! We found a rainbow ink pad shaped like a wheel in michaels. It retails for 17.99 but we used a 40% off coupon and got it for just under 10 I believe. I agree with the others about the tissue. We are gonna use johnson&johnson hand and face wipes from the baby ailse. They have no alcohol and don't leave a sticky residu nor will they leave a taste on your guests fingers! Plus safe for children since used on babies!

@SphynxLover- How else are you incorporating the eco theme? We are going for a natural/woodsy vibe. I think there would be a lot of overlap between our weddings styles. I'm curious.

I would put hand sanitizer out if u put tissues out. We are doing a tree finger print tree too.

@oregonemily

Mine is a lot of moss, wild flowers and bark. Where are you getting your decor?

You could try googling "inkless fingerprint pads." This type of ink just rubs off (like the one they use at banks.) They don't sell them in color, though. Only black.

Or I found these individually packaged fingerprint ink wipes you could set out:

http://www.idtechnologies.com/ProductDetail.aspx?productid=TOWINK

They are professional grade!

Thanks @Katrina. H!!!