For the CMYK Files: We highly prefer print-ready PDF files, but other acceptable file types are jpg, tiff, and eps files. We can also accept native files from Adobe Photoshop, Adobe Illustrator, or Adobe Indesign. However, sending us native files can potentially hold up or complicate your order if you have things such as: missing fonts, The fonts not loading properly, or missing images. With the modern-day ease of creating print-ready PDF files from virtually any native application, and all the positives that come with printers using them, it's the way to go if possible. For the Mask File (Raised Foil): All projects requiring special effects, such as Raised Spot UV, will additionally require files called Black Mask files. A Black Mask file is where you indicate in 100% black (K) where the effect is to be placed on your printed pieces. All Black Mask files for Raised Spot UV orders MUST BE created in a vector-based program (ex: Illustrator). Please also keep in mind that if you are intending your effect to be in alignment with your print shifts of up to 1/16" can occur. This is due to the fact that special effects are applied on separate machines from regular printing machines. For more information please visit this link https://www.4over4.com/metallic-wonderfoil-lenticular