Black Core cardstock, and printing your own proxies

Black Core cardstock is a laminated paper: two printable outer layers with an opaque black layer between them. The black layer is not decoration. It is there so that no light passes from one face of the card to the other.

It is how trading cards have been made for decades, and it is why a card fanned in a hand shows a thin dark line along its edge. White core and blue core stock exist for the same reason at different levels of opacity. Black is the most opaque of the three, and the one people ask for when a printed card has to sit in the same sleeve as a factory-printed one.

Print a card on both sides of ordinary cardstock and hold it under the light above a table: the back reads through the front as a ghost. Across a deck, that ghost is the difference between a card nobody looks at twice and a card everybody does.

An opaque core is what stops it, and it is the only thing that stops it. Print quality comes from the printer and the file; the feel comes from the weight and the finish; the opacity comes from the core. A heavy sheet with no core can still be read through, whatever it weighs.

Proxies and playtest cards, mostly: a deck somebody wants to test before buying into it, a card that has become too expensive to play with, a card that no longer exists in the format they play. Then custom and altered cards, prototypes for games being designed, and components for print-and-play.

The paper does not know which of them you play. What changes from one to the next is the size you cut to and the file you print, not the sheet you print it on.

• Magic: The Gathering
• Pokémon
• Yu-Gi-Oh!
• One Piece Card Game
• Lorcana
• Flesh and Blood
• Digimon

The games named above are the trademarks of their respective owners. We are not affiliated with, endorsed by, licensed by or connected to any of them. We sell blank paper: we print nothing, and we supply no card artwork or files.

Heavy cardstock is not what a desktop printer expects. Three things decide whether yours will take it: the paper path, since a straight or rear feed bends the sheet far less than a cassette does; the media setting, where the heaviest one the driver offers slows the machine down and lays down more ink; and patience, feeding sheets one at a time and letting one side dry before printing the other.

Double-sided printing asks for one thing more. The two faces have to line up, or every card is cut off-centre. Print one test sheet with registration marks and measure it before you print a hundred.

Which machines actually manage it is not something we guess at. The product page lists the printers people have reported, and says of each whether it was tested or only reported.

A proxy stands in for a card you do not own: for playtesting, for casual games among people who agreed to it, and for keeping an expensive card out of a deck box that travels. It is not a counterfeit. It is not sold as genuine, not passed off as genuine, and not welcome in sanctioned tournaments. We sell blank paper for the first of those and have no interest in the second.

Black Core inkjet cardstock, A4, in several pack sizes, shipped from Europe. What it is made of is recorded exactly as we entered it, here and on its own page.

There is no sample on sale at the moment. The characteristics on the product page are the closest thing we can give you before you order.