Simulated process vs spot colour separation

Spot colour: one ink, one flat area

Spot separation is the direct route. Every colour in the artwork becomes its own ink, mixed before the run and printed as a flat solid with no halftone.

A three-colour logo gives you three screens. The colour on the garment is the colour in the bucket, because nothing is mixing with anything. Registration is easy, since the inks mostly do not share long edges.

It has one hard limit: every shade costs a screen. Artwork with a gradient or a photograph cannot be separated this way, because the shades run into thousands.

Simulated process: a few opaque inks and a halftone

Simulated process reproduces a photographic image with a limited set of opaque inks, each one printed as a halftone.

The word simulated is literal: process printing imitated with spot inks. The inks stay opaque and stack on each other, and the shades between them come from dot size rather than from pigment mixing. Where the red ink covers 40 percent, the base shows through the gaps and the eye reads a blend.

This is how anything photographic gets printed on dark garments: illustrations, portraits, complex gradients. It is the most common kind of separation in screen printing today, and it is what ColorLayers does.

Which one your artwork needs

The rule is short: count the colours rather than judging the complexity.

• Up to six clean colours with no transitions. Spot. Cheaper, exact on colour, simpler on press.
• Any gradient, shadow or photograph. Simulated process. Spot inks cannot print it at all.
• A brand colour that has to be exact. Spot, even inside complex artwork. A halftone always drifts a little; a solid does not.
• A dark garment. Whichever separation you choose, add a base. Opacity alone does not save an ink on black.

Mixing the two inside one job is normal and common: the background screened, the logo a solid spot.

How many inks simulated process costs

More than it looks, and fewer than the fear suggests.

The working range is four to eight inks plus a base. The default profile assumes seven inks in a pass, which is what a typical carousel holds, and warns as soon as the palette goes past it.

Every extra ink is a screen, a station, a flash and a registration risk. Reducing the palette is therefore money rather than tidiness: the difference between seven inks and ten shows up in the invoice and often does not show on the shirt.

Each ink's share of the area is visible before you export. An ink taking a fraction of a percent almost always folds into its neighbour for nothing.

Why this is not CMYK

Four-colour process exists in screen printing too, and confusing it with simulated process is expensive.

CMYK depends on transparent inks: they overlay, light passes through the film and reflects off the substrate. That is why four inks suffice, and why they give you nothing on a black shirt, where there is nothing to reflect from.

Simulated process depends on opaque inks that cover what is under them. It needs more of them, and in exchange it prints on dark. The reachable colour range is wider too, because you are not confined to four pigments.

Briefly: CMYK for light substrates and smooth stock, simulated process for dark garments and fabric.

How ColorLayers does this separation

The palette is taken from the image itself, and every pixel goes to the ink that carries it most closely. How far a colour may sit from an ink and still belong to it is the tolerance.

The tone masks are then screened at the angle and line count from the shop profile, an underbase is built from the ink you choose, and everything is measured against your own minimum line and gap.

The result is deterministic: the same file with the same profile gives the same plates on any machine, a year later. The report records the line count, the angles, the print order and the profile, so a reprint is a repeat rather than a reconstruction.

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