To ensure that Spot Gloss and Foil effects are applied properly, please use 10pt size or larger for fonts. Line strokes should be at least 1pt thick. Please also be advised that small gaps, and thin strokes. and extremely fine details may pool together or break up when the effect is applied. When doing a Spot UV business card, postcard or pocket folder a Spot UV mask must be created and uploaded with your full color file. The file for the Spot UV mask MUST ONLY be black and white (100% Black). 100% Black in the areas you want the Spot UV effect to be on, and white in the areas you do not want the Spot UV. Click for Details. There may be up to a 1/16" shift on the placement of the spot UV on your order. Keep this in mind if you are trying to align spot UV with other printed artwork on the card.