The success of your project starts with understanding how to setup your files for screen printing on paper. The number one mistake designers make when submitting files is setting files up the same was they do for screen printing on fabric with everything knocked out. File preparation for fabric is generally fairly straightforward, but paper file prep tends to be a bit more complicated as it requires a mix of trapping and overprinting. Reviewing the following settings is a good place to start.
File Format: submit final file as a Photoshop PSD or Illustrator AI.
File Dimensions: confirm file is 100% size final print size.
File DPI: Photoshop files are required to be set at 300dpi.
File Color Mode: set file color mode to CMYK to give a better visual representation of how inks will print and allow for quicker final prep.
Color Swatches: if you are using a physical Pantone swatch book to pick ink colors, use the uncoated book and label each layer with the color of the ink. When working in Illustrator, convert swatches to global CMYK swatches. If you are unfamiliar, please visit the following link to help.
Layers: every ink color must be on it's own layer with no other colors or elements on that layer. Name layer with ink color.
Ink order: when screen printing on paper, you generally print light to dark which allows the dark inks to trap over the lighter inks. There may be some exceptions so it is usually good to confirm before final prep
Color density: all colors must be set to 100% density of the ink color or converted to halftones (more details).
Line thickness: for dark lines over light colors, lines should be around 1pt (4-5 pixels) thick. For light colored lines reversed out of large solids, it is recommended that lines are closer to 2pts (8-10 pixels) as they can fill in when surrounded by large amounts of ink. PLEASE NOTE: In Photoshop, at 300dpi, 1pt = 4-5 pixels.
Bleed: when colors go to the edge of the design, you need to add a bleed and extend the art .125" past the edge to allow for trimming of final prints.
Illustrator: add .125" bleed to all 4 sides in Document Setup.
Photoshop: add .25" to both width and height in Canvas Settings and keep the art centered, which adds .125" to all 4 sides.
Registration/Trim Marks: please do not add for projects Ink Lounge is printing as I have specific templates.
Knockout: shapes generally need to be knocked out of colors to allow the paper or ink to show through from below, but trapping needs to be considered as often shapes will simply overprint.
Trapping: this is the relationship created when 2 colors touch. When a lighter color is 100% surrounded, generally you can simply add a 3-5pt stroke to that shape. It becomes more complicated when there are gaps between other colors so shapes must be adjusted manually.
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. For larger areas you will knock out and trap.
Trap or overprint: the image below 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.