The file can only be black and white.
All black areas should be 100k or only 100% black with no other colors added.
Black in the areas you want the foil and white in the areas you do not want the foil.
If you order a Foil Worx job with Spot UV, you must provide separate mask files for the Foil (foil mask) and UV (spuv mask), in that case up to 6 files will need to be provided.
However, please keep in mind that the Foil and UV can’t overlap.
Also please avoid using small / fine text or fonts for foil objects. For best results, please make sure that foil coverage is less than 50% of the artwork area
Also, be aware that there may be up to 1/16″ shift on the placement of the foil. Keep this in mind if you are trying to align foil with other printed artwork on the card.
Please see images below to see what mask files should look like. Remember that black in the mask file must be 100k where you would like the foil to go.