Artwork Colour Separation

Colour separation is the step where a design becomes something a press can actually print. Every colour in the artwork is split onto its own layer, one layer per screen, with the halftones, angles and overlaps set so the colours land on top of each other correctly when the garment runs. Get it right and the print looks like the design. Get it wrong and no amount of skill on the press will save it.

We produce separations at our Leicester site for screen printing, and we have been doing it for over 30 years. What makes that useful to you is where the separations are made: in the same building as the presses that print them. The person splitting your artwork knows what the mesh will hold, what the ink will do on that fabric and how much registration drift to allow for, because they will see the job come off the machine.

We separate artwork for our own screen printing work and for brands and printers who want the separation done properly before the job goes anywhere near a screen.

What Colour Separation Does to Your Artwork

A screen press lays down one ink at a time. It has no idea what your design looks like. All it can print is whatever is open on each screen, in the order the screens are set, in the ink loaded into that head. Separation is the translation between a flat design file and that sequence of single-ink passes.

The choices made at separation stage decide almost everything about the finished print: how many screens the job needs, how the tones blend, whether fine detail survives, how the print feels in the hand and how close the colours sit to the ones on your screen at home. It is also where cost is set, because every extra screen is another setup.

Types of Colour Separation We Produce

Which method suits your job depends on the artwork, the garment colour and how many screens the run can justify. We will tell you which one we would use and why before anything is committed.

Spot Colour Separation

Each colour in the design gets its own screen and prints as a solid, unbroken ink. This is the method for logos, type, flat graphics and anything where the brand colour has to be exactly the brand colour. It gives the most predictable match and the cleanest edges. The limit is the palette: a design with a lot of colours becomes a lot of screens.

Simulated Process Separation

A photographic or heavily blended image built from a small set of opaque inks printed as halftones, which the eye blends into continuous tone. This is what you want for detailed or photographic artwork on a dark garment, because the inks are opaque and sit over a white underbase instead of relying on the shirt showing through. It is the most demanding separation to build and the one where experience shows most clearly.

Four Colour Process (CMYK) Separation

Cyan, magenta, yellow and black, printed as halftones in transparent ink. Because the inks are transparent, they need a white or very light garment underneath to read properly. CMYK gives a wide tonal range on light fabric and keeps the print soft, but it cannot hit bright saturated colours the way a spot ink can, so a design that lives or dies on one vivid colour is usually better served elsewhere.

Index Separation

The image is converted into square pixels of solid colour at a fixed size, with no dot shape and no screen angle. Removing the angle removes the risk of moiré, which makes index a good answer for busy, noisy or highly detailed artwork that fights conventional halftones. It tends to use more ink and often more screens, so it is a quality decision more than an economy one.

Greyscale and Single Colour Halftone Work

Single ink, full tonal range, built entirely from dot size. Cheap on screens and genuinely effective on the right image. Worth considering when a photographic look is wanted on a budget that will not stretch to a six or eight colour simulated process job.

Underbase, Trapping and the Detail That Decides the Print

On a dark garment, colours printed straight onto the fabric go dull and muddy. An underbase, usually white, is laid down first so the colours above it have something to sit on and read true. Building the underbase is a job in itself: too heavy and the print goes stiff and plasticky, too light and the colours sink into the shirt. It is normally choked back slightly from the edges of the colours above so no white halo peeks out.

Trapping is the same idea applied between colours. Presses drift a fraction as a run goes on, and if two colours meet exactly on the line, that drift shows as a white gap. Overlapping the edges by a small amount hides it. Neither of these things is visible in the design file, and neither is optional if the print has to hold up across a full run.

Halftones, Line Count and Mesh

Tone in screen printing is an illusion made of dots. The line count sets how fine those dots are, and it has to be chosen against the mesh that will hold them. Push the line count too fine for the mesh and the small dots fall out, taking the highlights with them. Go too coarse and the pattern becomes visible in the print.

Dot angles matter as much. Screens set at the wrong angles to each other produce moiré, and so does a dot pattern fighting the weave of the fabric. Setting line count, angle and dot shape correctly for the specific garment and press is most of what separates a separation that prints from a file that merely looks separated.

Artwork Files We Can Work From

Send the best version you have. For spot colour work, vector artwork is ideal, so AI, EPS, PDF or SVG with the type outlined and the colours defined. For process and simulated process work, a layered high-resolution raster file at or near print size gives us far more to work with than a flattened one.

The usual difficulty is a small JPEG pulled off social media or lifted from a website. We can often still get a printable separation out of it, but the honest answer is that the ceiling on quality is set by the file, and it is worth ten minutes finding the original before we start. If you are not sure what you have, send it over and we will look.

Separation on Its Own, or as Part of the Print

Plenty of the separation work we do feeds straight into our own presses, as part of a screen printing order that runs from 25 pieces per design. If you print elsewhere, or in house, we can supply the separation as a standalone piece of work and hand you the files.

Separation is a screen printing discipline, so it does not apply in the same way to every method we run. Digital printing and Print On Demand® handle colour differently and carry no minimum order, which makes them a better route for full-colour artwork in small quantities. Hybrid printing combines the two, and embroidery needs digitising instead. If you are not certain which route your artwork wants, describe the job and we will point you at the right one.

Colour Separation Turnaround

Separation time depends on the method and the state of the file. A two colour vector logo is quick. An eight colour simulated process image built from a supplied photograph is not, and rushing it produces exactly the kind of print nobody wants to pay for. We confirm the timescale when we quote.

Where the separation feeds one of our own print orders, standard production turnaround is 5 to 10 working days from approval of artwork and payment. Tell us your deadline at enquiry stage and we will be straight with you about whether it fits.