A checklist for screen printing specialty items
Basic screen printing requirements:
T-shirts, mugs, and other objects will be screen printed, with spot colors.
Screen-printing ink forms a thick layer and it is quite opaque. Blending colors by overprinting can be done with lithography, letterpress, and digital presses, but can be unpredictable or impossible with the opaque screen-printing inks.
Most screen printers can print halftones, with dots of 45 lpi or less. It is best to ask them what they can do.
Formating your files
Files must be built to the vendor requirements. Printers won't try to guess the size and position of your images. Many printers publish dimensions and guidelines for files, for example: https://www.4over4.com/learn/mugs/how-to-set-up-your-files-for-mug-printing/ http://www.threadbird.com/file-prep https://printaura.com/image-requirements/ Your native print-ready files should be the final printed size. Your native files will have spot colors applied to all elements. Any overlapping elements will have the appropriate trapping or overprinting. Always check your separations; Illustrator, InDesign, and Acrobat have tools. It is common to find CMYK where you don’t expect it and duplicate colors, so check often. It is wise to convert the type to outlines.
PDF files will embed the fonts, but it is safer to make the PDF from a copy of your native file with outlined type.