Any of the following: TIFF, PSD, JPG (quality 12), or a vector format for digital illustrations. You do not need to resample the file: we will assess the necessary percent magnification on the basis of print size you require. Please leave the file in its original colour profile. Do not convert to CMYK four-colour: our printers can reproduce a larger colour space from RGB. We accept both 8 bit and 16 bit files. To send the file we recommend using “WeTransfer”, available at