Spot colors or process: which does the design need?
Screen printing puts down one ink per screen, so how you get the colors you want decides how the artwork has to be built.
Spot color means each color is a premixed ink laid down as a flat, solid area. One screen, one ink, one color. This is how most garment work is printed: it gives strong, consistent color on fabric and matches brand colors exactly. The artwork is simple in structure and unforgiving in practice, because every color has to exist as its own closed shape, not as a region that merely looks like one color.
Process builds color from overlapping halftone dots of cyan, magenta, yellow and black. It suits photographic images with continuous tone, and it is the wrong tool for a two color logo. Simulated process, which uses halftones of several spot inks, sits in between and is common for detailed artwork on dark garments.
Almost every logo job should be spot. Where the artwork is a photograph, no amount of vector work will turn it into flat spot shapes, and the job belongs in process or simulated process instead.
How should the colors be referenced?
By number, not by eye. The Pantone Matching System gives each spot color a reference and an ink formulation, so a printer anywhere can mix the same color. Pantone's Formula Guide set covers all 2,614 spot colors in the Pantone Graphics System across coated and uncoated stocks, with the ink formulations included.
Two practical points follow:
- Coated and uncoated are different books for a reason. The same ink reads differently on different surfaces, so a Pantone reference is only complete when you say which one you mean.
- A spot color and its process equivalent are not the same color. Pantone publishes the Color Bridge guide precisely to show side by side comparisons of Pantone spot colors against their closest industry standard CMYK matches. If a job switches from spot to process, expect some colors to shift.
In the artwork itself, apply the reference as a named spot swatch rather than typing in a similar looking RGB value. AI, EPS and PDF all carry named spot swatches; SVG does not, as covered in vector file formats.
What has to happen to fonts and fine detail?
Ink spreads slightly as it is pushed through the mesh, and the mesh itself can only hold so much detail. That sets a floor on how thin a line can be and how small type can go. Screen printers publish their own art guidelines for this. Oregon Screen Impressions, for example, asks for lines no thinner than 1 pt, fonts no smaller than 8 pt, with larger sizes for reversed or negative space text, and raster elements at 300 DPI at print size or larger.
| What the printer checks | Commonly published guideline | Why |
|---|---|---|
| Line weight | No thinner than 1 pt | Thinner strokes break up or fail to hold on the screen |
| Type size | No smaller than 8 pt | Ink gain closes up small counters and thin stems |
| Reversed type and lines | Heavier than the positive minimum | Ink spreads into the gap, so a knocked out line narrows as it prints |
| Raster elements | 300 DPI at the finished print size | Enlarging afterwards cannot add detail that was never captured |
| Fonts | Converted to outlines | A missing font is silently substituted, changing the shapes |
| Overlapping duplicates | Merged into single shapes | Stacked or doubled paths confuse the separation |
Treat published numbers as a floor, not a target: the safe minimum on a given job depends on the mesh, the ink, the garment and the press, so ask the shop printing the run. Where a logo has detail below the floor, it has to be thickened, opened up or dropped, and the client should be told which. Our free EPS and AI file viewer opens a supplied AI or EPS in the browser, so you can look before you commit to a deadline.
What do overprint and trapping do?
When two colors meet, the file has to say what happens at the boundary. Knockout removes the lower color where the upper one prints, so the inks sit side by side. Overprint leaves the lower color in place and prints the upper one on top of it.
Both are fine until the press shifts. No press registers perfectly, and when two colors butt up exactly, any movement leaves a sliver of bare garment along the join. Trapping is the fix: a deliberate small overlap between adjoining colors, traditionally handled as chokes and spreads, where one shape is expanded slightly or the other pulled back so the join has a margin to move within.
How much overlap is a press question, not an artwork question. In commercial offset at 150 lpi, traps are usually between 1/150 and 1/300 inch, and those values are commonly increased when one of the colors is black. Garment screen printing runs at far coarser tolerances, so the printer running the job sets the amount. What the artwork has to provide is the structure that makes trapping possible: separate closed shapes per ink, in a known stacking order, on paths that can be offset cleanly.
On a colored shirt, an area of the design that matches the garment needs no ink at all. Knocking it out of the artwork removes a screen from the job, and that decision belongs in the artwork stage, before anyone counts colors for a quote.
Why do separations come from clean vector paths?
A separation is one output per ink: the film or positive used to burn each screen. Pulling those from a file is mechanical if the artwork is built properly and guesswork if it is not.
With clean vector, each ink is already a closed shape or a group of them, so a separation is a matter of isolating the objects that carry a swatch and outputting them. Nothing has to be interpreted, so the result is repeatable and the edges are exactly where the designer put them.
With a raster file, or an auto-traced file carrying hundreds of near-identical sampled shades, none of that holds. There are no objects to isolate, only pixels that happen to be similar. Someone has to decide where one color stops and the next begins, and a compressed JPG has already blurred that boundary: Adobe notes that images with clean edges and lines lose some of their sharpness in JPEG compression. The separation becomes an interpretation, which is how two runs of the same logo end up different.
This is why print prep and separation are two jobs. If your artwork needs rebuilding as spot color vector first, that is screen print vector art; if it is already clean vector and you only need the channels output for film, that is color separation for screen printing. Why the file type matters at all is covered in raster vs vector, and the rest of the cluster sits in the vector artwork guides.
Rather have it digitized for you?
Hand-digitized files from $10 per design, back in 4–8 hours, in every machine format.
Get a free quote →Frequently asked questions
Sources
- Oregon Screen Impressions: screen printing art guidelines (1 pt lines, 8 pt type, 300 DPI)
- Pantone: Formula Guide set, coated and uncoated
- Pantone: Color Bridge Guide Coated (spot to CMYK comparison)
- Trap (printing): misregistration, chokes and spreads, typical trap values
- Adobe: JPEG file format (compression softens clean edges)
Sources checked 21 September 2026.