The success of your project starts with understanding how to setup your files. File prep for fabric is fairly straightforward but paper file prep can be extremely complicated which can hold up the schedule. The following is a good place to start and many tips will be common to either. The key difference for fabric is you can skip layers and generally you will not need to trap as you don't overlap colors. There will always be exceptions, plus different screen printers will have unique specifications.
FILE TYPE Illustrator AI or Photoshop PSD.
File DPI If it is not a vector image, it needs to be 300dpi at 100% printing size.
FILE DIMENSIONS File dimensions should be the same size as the final print. If you have ink going to the edge, then you must add a "bleed" of .125" to all 4 sides. From there you then also extend the art .125". The bleed can often be added with the bleed function in most programs.
COLOR SPACE Design in CMYK to give a more accurate visual idea of how inks will print - RGB has colors that don't exist in inks.
COLOR SWATCHES All swatches should be set as global CMYK swatches when working in Illustrator. Here's a link to help If you are unfamiliar with Illustrator settings. When using a physical Pantone swatch book to pick ink colors, select from the Uncoated book.
COLOR DENSITY All colors must be set to 100% density of the ink color.
HALFTONES As a good starting point–when converting to a bitmap, at 300dpi use 30-35lpi. It is also good to over emphasis the contrast as from about 85-99% density tends to fill in and print solid, since 1-15% density may not expose and can disappear.
LINE THICKNESS For dark lines over light colors, lines should be around 1pt in thickness. In Photoshop, at 300dpi, 1pt = around 4-5 pixels. For light colored lines reversed out of large solids, I recommended making lines closer to 2pts (8-10 pixels) as they can fill in when surrounded by large amounts of ink.
KNOCKOUT Shapes need to be knocked out of colors to allow the paper or ink to show through from below.
LAYERS Every ink color must be on it's own layer and ideally each layer should also be labeled with the color of the ink.
INK ORDER For paper, you generally print light inks to dark inks. This allows the dark inks to trap over the lighter colors.
TRAPPING This is the relationship created when 2 colors touch with several ways to create the trap. When a color is 100% surrounded, generally you can simply add a 3-5pt stroke. It becomes more tricky when colors go between other colors.
OVERPRINT When you have darker ink colors printing over patterns or small areas of lighter colors, you will generally overprint the dark inks instead of trap.
REGISTRATION MARKS Please do not add for projects I am printing for you as I have a specific template setup.
GUIDES Please do use as they will help make sure your margins are equal.
Working Example for Paper
The image to the right is available to download as a Photoshop PSD file or Illustrator AI file to help you better understand the relationships between colors when screen printing on paper.
Please take some time to investigate the intersecting relationships of ink colors to understand the differences.
For issues not addressed, such as printing on dark papers, gradients or percentages of colors, printing photos, etc., please call to discuss setup.