What printing techniques or folding tools can I use to hand fold a commercially printed design without it cracking?

Question

I recently created some tickets that were professionally printed then hand folded into an origami heart shape.

We used 170 GSM paper and I'm not sure what ink the printers used.

They arrived beautiful, but once the folding began the ink started to rub off around the folded edges. Our bodge was to colour in the immediately visible edges with a colouring pen.

It was for a student event with a tiny budget, I wouldn't do that with a real client.

What ink and paper combination would be best to make sure the ink doesn't rub off in future?

What manual tools are available for hand-folding?

Here's an example (the example was coloured in with a badly matched shade of red and was not sold, others were much better but I don't have any left):

Answer 1

Ink cracking is very common and is always an issue if the paper is not previously run through a scoring or creasing process.

The problem is low ink penetration. The ink is just a coat on the paper. It does not really wet it and that makes it crack on the surface. The cracking is even more pronounced on digital non-offset prints. Your example has less cracking than I would have expected.

Possible Solution:

Sublimation. There are sublimation offset inks for this. Sublimation printing has the benefit, that the ink ends up inside the printed support and can not form a coat (and therefore it should not crack). I have no experience with sublimation printing on paper. Just with polyester plastics where it works incredibly well. The prints are extremely scratch resistant. A lot of snowboards are printed this way.

I don't know much about sublimation on paper and how much the inks really penetrate the paper. You'd have to find a printer with experience or willing enough to make some test...
You'll probably not get a glossy finish. Saturation tends to suffer a bit, too.

Answer 2

Some additional factors:

Creasing: You can use a bone folder or a burnisher or anything that will break the fibers of the paper without tearing it : tapestry needle, an old ink pen (double, triple check it's out of ink and keep it for later use), a fork, any blunted pointy end...

A common mistake to avoid is that people usually crease inside the fold and you should crease outside like so.

Paper grain: If the folds are made against the grain, they are more likely to crack. You have a lot of folds in your project and in all directions so that wouldn't be avoidable. Here is some extra information about paper grain in folding and how to check in which direction is the paper grain.

Ink rubbing off: Ink is more likely to rub off on some coated papers. You can avoid it by laminating your piece but it changes the finish completely. I've encountered a particularily bad run of ink rubbing off on business cards before and my printer did a rerun for free with lamination. I don't think they print in that specific paper anymore, it was a bad combination.