Foil
Foil cards were printed with a shiny layer on the paper, which causes a reflective rainbow effect when it catches the light. Most foils came from random insertion into booster packs, although some Promotional and Tengwar cards were also printed in foil. In general as a result, foil versions of cards are rarer and more expensive than their nonfoil counterparts, and are the holy grail for many collectors.
Decipher artists put time and effort into customizing the foil effect for each card, masking the image so that different parts of the image would have the foil effect applied. Thus, a few different kinds of emphasis were used:
Here on the wiki, we have successfully gathered images for nearly every foil card known. See List of Foil Cards for a gallery (tho be warned, it takes a while to load and browse).
Movie Era
For the first 10 sets, each set was printed twice: once as standard cards, and again as foil. Each booster pack had about a 1 in 6 chance of having one of the cards randomly replaced with a foil card of a random rarity. This meant that collecting full foil sets was significantly more unpredictable, and also could result in some interesting booster packs: for instance, this could result in a booster with two rares (one of them foil, replacing one of the common or uncommon cards). Due to the mechanics of inserting foils into early sets, it was possible - though very unusual - to open a pack with more than one foil card plus an ordinary rare.
In the Fellowship of the Ring set (and presumably for all movie-block sets), the odds of which card was inserted as a foil varied based on its rarity, which was as follows [1]:
- 1 Common foil every 13 packs
- 1 Uncommon foil every 18 packs
- 1 Rare foil every 26 packs
Each of these chances was calculated independently, which results in each booster having a ~17% chance of having at least one foil, which is where Decipher's 1 in 6 advertised chance calculation comes from.
Shadows Era
Starting with the Shadows set, parallel foil sets were no longer created, and instead specific cards from each set were re-issued with new Collector's Info. 18 cards made up the Legends line, and 9 cards made up the Legends Masterworks line.
Production Process
The foil effect on cards actually comes from the paper, which has a shiny layer added to it. Decipher produced foil images that pop by printing foil-obscuring ink on the card so that only parts of the image would shine with the rainbow effect. This was done by producing a black-and-white mask for each foil image that looked like this:
The black indicates where there would be no foil, and the white indicates which parts will have both the printed color and the rainbow diffraction foil effect.