Vector art for screen printing
You cannot separate what you cannot select. That is the whole problem in one sentence: a screen needs its own geometry, and a raster file has none to give. Everything below follows from it.
What the press actually needs
Each ink gets its own screen, so each ink needs its own selectable geometry. A flattened raster cannot be split into screens no matter how clean it looks, because there is nothing to separate.
RGB is a light model; you are mixing pigment. Colours need to be named as spots so the same file prints the same on the next run. A traced file that comes back with 40 near-identical greens has to be merged down before it is usable.
Gradients only exist on press as dots. Too fine for the mesh count and they fill in or fall off entirely. Photographic detail carried straight through from a customer photo is the usual reason a print looks muddy.
Hairlines that read fine on screen disappear on a garment. Anything below roughly half a millimetre is a candidate to break up, especially on a coarse mesh or a textured fabric.
From customer file to burnable separation
Four steps. Only the first can be automated end to end, and it is the one that costs the most when it is done by hand.
Get real paths out of the JPG, PNG or screenshot they sent. This is the step that decides whether everything after it is possible.
An automatic trace can return dozens of shades where the design has four inks. Collapse them to the actual ink count before separating.
Name the colours, add the overlap the press needs so registration drift does not show a white line.
Thin strokes, tiny counters in letterforms, isolated specks left by the trace. These are what come back as a reprint.
Be clear about the boundary. Converting the file is not the same as separating it. Anyone selling you automatic separations for a multi-colour job is overselling. What automation removes is the redraw — steps 2 to 4 stay with your pre-press.
Questions from the shop floor
Only for a single-colour job where you are happy to output the whole thing as one solid shape, and even then the edges will carry the pixel stair-stepping. For anything with more than one ink you need separable geometry, which a raster file does not have.
It gives you the paths, which is the hard part. It does not give you a press-ready separation: you still merge the colour count to the real ink count, set spots, and add trapping. The value is that it removes the redraw, not the pre-press judgement.
Those are simulated-process or four-colour-process jobs, and the answer is different: you are not looking for clean paths, you are looking for a good halftone plan. Automatic vectorisation is the wrong tool there and will make it worse.
That is a redraw, and it should be one. Someone has to decide what the mark is supposed to be where the print has cracked or the fabric has distorted it. Charge for it — that is real work.
Split the work by difficulty. Clean logos, screenshots and decent PNGs go through automatic conversion in seconds. Sketches, photos of samples and process jobs go to whoever does your art. Most shops find the first group is the large majority, and it is the one that was quietly eating the budget.
Shop owners: would automatic spot-color separations help?
We are weighing a tool that takes the vector you just made and outputs one print-ready film per ink color, registration marks included. It does not exist yet, and we only build what real shops ask for.
Yes, I would use that — tell us how you separate todayOr write to contact@vectosolve.com with the word separations.
If screen printing is your business, you are probably paying per file.
An outside art service charges 6 to 26 dollars a logo and comes back the next day. Redrawing it yourself costs half an hour you could bill. A year here is $49 for 25 conversions every month, every machine format included, which works out cheaper than two outsourced logos.
Everything on this page stays free. This is only worth it if you do volume.