Digital short runs

Single prints and small runs are usually produced by digital print.
There are two main technologies here: direct to lens print on UV machines and inkjet printing on photo paper that is later laminated to lens by hand.
The first method allows for producing from one to  hundreds of copies, the other one serves the purpose of preparing single print only, so called "proof of concept".
Bear in mind that "proof of concept" doesn't show 100% final effect in litho printing. The effect and color are just approximate. In digital printing "proof of concept" is a 100% final effect.

Direct to lens method is used where the edition varies btw over a dozen and hundreds of invitations, postcards or similar prints, only then it is financially economical.

Inkjet print on photo paper method  and lamination to lens comes in play with proof of concept or some artistic prints. The disadvantage is  sensibility to mechanical damage and humidity.