When submitting your artwork, we recommend supplying logo files and illustrations as vector files rather than PNGs or JPGs. This is because these file formats are flattened and cannot be edited.
For instance when setting up your artwork for the application of a special effect, we must be able to extract elements of the logo or illustrations in order to create a seperate layer so the printer can recognise where the effect must be applied. If the PNG or JPG is simply inserted in these areas, the printer will not recognise it properly because these files are "flattened".
Similarly, we often receive logo files with an unwanted background colour. Unfortunately we cannot alter the background colour because of the same reasons mentioned above.