Card marking

The first attempts to mark playing cards involved bends, crimps and tiny pinprick bumps known as "blisters", resembling the Braille script.

Hustlers have used various inks, pigments and scratches, to add or remove lines or patterns from the back of the card design.

[clarification needed] Traditional block-out and cut-out work have the disadvantage that they must be read close-up, because the marks are small.

Cut-out work is use of a razor to scrape off some of the printed areas of the card, such as adding (cutting out) a white bird to the back design.

Placing a drop of alcohol on a card and then looking at the finish by reflecting light off the back reveals the dulling effect that these cheap solutions can cause.

Pęczarski's 1845 work Card-sharpers by candlelight , depicting a card whose back has been marked, possibly using wax to add lines which become slightly visible when reflecting light
Casinos alter playing cards used at table games before they are sold or given away to prevent cheaters from buying them to cheat at table games.
By subtly tinting different body parts of this small "angel" feature on the back of a playing card - the head for an ace, the left wing for a king, etc. - the card's rank can be discerned. The two is left unmarked.