Simulated process color separation — and where automation stops

What simulated process actually is

Rather than splitting an image into cyan, magenta, yellow and black and printing translucent process inks, simulated process picks a set of opaque plastisol-style inks that suit the image and builds a tonal channel for each one. Every channel is halftoned, and the whole stack sits on a white underbase so the colors read on a black or navy shirt instead of sinking into it. It is the reason a photographic print on a dark garment looks bright rather than muddy, and it is the separation people pay outside services to do for them. What that costs, from published prices: ContractPrinter's photorealistic sim-process tier is $85 and up per design with revisions at $5 each (checked 28 July 2026), and that is the top of the field rather than the middle of it — 24 Hour Seps, Scott Fresener's own service, lists a flat $65 per set for any number of colours (a promotional rate when checked; their volume packs go lower), Burn My Screen a flat $60 per design, and Color-Separation.com $15 to $50 including the underbase and highlight white (all checked 29 July 2026). Call it $50 to $85 for a hard photographic design, plus a revision cycle each time you want a change.

Why there is no one-button version of this

Fully automatic simulated process is unreliable in every tool that sells it. The established desktop packages — vendor-listed at $229 a year for Separation Studio NXT, $345 for T-Seps and $399 for UltraSeps when we checked on 28 July 2026 — all keep manual channel control, and the newer AI-branded services keep it too — because a photograph does not contain a correct answer that an algorithm can find. Skin tones, the point where a red channel should hand off to a magenta one, how hot to run the highlight white: these are press judgements informed by your inks, your mesh and your garment. The auto pass here is therefore a starting point. A retained local Spot or Index palette supplies one density slider for each whole ink channel; a direct Simulated-process render does not expose those sliders before or after its ZIP download. Even on the retained-palette path, density cannot reshape only the shadows, midtones or highlights the way a tone curve can. Anyone selling you a single button for this is selling you a reprint, and anyone claiming this workspace has the full curve control of the established packages would be overstating it too.

What the render produces

From the clustered ink set: one tonal channel per ink, a choked underbase generated from the combined coverage and pulled inward to reduce white flash at the edges, a separate highlight white so the brightest highlights print last and hit hardest, per-ink choke and spread, a dot-gain compensation curve, and halftone screening at separated angles. The automatic angle table has distinct entries for up to eight colour plates; above that it repeats angles and the ZIP manifest warns that some pairs can moiré. Selecting simulated process turns halftoning on, so the initial output targets pre-halftoned 1-bit film at 600 dpi; the manifest records the effective DPI if the 16,800px/200MP output caps clamp it. Turn halftoning off when your RIP should receive continuous-tone grayscale plates. Registration marks are a toggle. The shipped workspace has no separate automatic-trapping control.

What the available override actually does

On a retained local Spot or Index palette, each density value scales how much ink that channel lays down across its whole tonal range. Pull a channel back when it dominates the image; restore it toward 100% when it has become too weak. That is useful, but it is not a tone curve: you cannot remove red only from the upper midtones or lift only a hollow shadow in the current workspace. The underbase has an on/off control and a choke amount in pixels. Highlight white is on or off; its tonal cutoff is currently the renderer's fixed default, not a slider. The always-visible controls are garment colour, underbase, dot-gain strength, halftone frequency, dot shape, the non-CMYK angle set, output DPI, registration marks and optional vector tracing. Ink count, tolerance, per-ink density and choke/spread affect a custom paid palette only after you run a free local separation; edits to that retained list are then sent with the render. A direct paid render instead chooses its own palette and returns only the ZIP. The ZIP includes a proof over the garment colour. If a problem lives in only one tonal band, take the plates into a channel editor or use a human separator rather than pretending the density slider is finer than it is.

How to read a bad channel set

Specific symptoms still tell you where to look. Skin that has gone grey or muddy often means too much of a dark channel; pull that whole channel back and check the proof. Skin that has gone plastic-orange points at the warm channel. Banding across a smooth gradient or a colour problem confined to midtones needs a tonal curve, which this workspace does not expose — that is the point to continue in a channel editor or hand the job to a separator. A chalky print or a shadow that will not go dark often points at too much underbase, while highlight white washing through the midtones means the renderer's fixed highlight cutoff does not suit this image; here the available correction is to turn that plate off, not tune its threshold. A plate that looks nearly empty may not survive your mesh and emulsion, so pull other channels back or drop it deliberately rather than burning a screen that will not print. And a colour that looks right alone but sits dead on the proof is the reminder that you are separating opaque ink on fabric, not light on a monitor.

Why print order is load-bearing when the inks are opaque

With translucent process inks, order matters at the margins. With opaque inks it changes the image, because each ink genuinely hides what is beneath it — the last plate down is the one you see. The paid engine currently chooses underbase first, then its light-to-dark ink order, then highlight white last; that sequence is recorded in the ZIP manifest and plate numbering. The local spot/index plate list can be reordered before a local export, but the shipped client does not send an explicit order override to the paid simulated-process renderer. That is a real limitation because the channel solution itself depends on order. If your press requires a sequence you already trust, inspect the manifest and treat this automatic result as a starting point; this is not yet a renderer in which you can make your own sequence authoritative.

Priced so you are not afraid of the sliders

Simulated process is 10 credits per image, and for 24 hours after that render you can re-render the same image as often as you like at no extra cost. That is deliberate: a per-render charge would teach you to guess instead of iterate, and iterating is the entire method. Twenty-four hours is also enough to render, burn a test, print it, and come back with real density or choke adjustments the same day. A print-ready render is 10 credits, a small share of a month’s allowance, and a one-off pack adds credits that never expire — see the pricing page for current prices in your currency. Compare that with per-design separation fees: ContractPrinter's published tiers ran $15 for one or two spot colours up to $85 and above for photorealistic simulated process plus $5 a revision (28 July 2026), while the flat-fee services sit lower — 24 Hour Seps at a promotional $65 per set for any number of colours, Burn My Screen at $60 (29 July 2026). Or compare it with a desktop package you buy once and then need a Windows machine and, for the plug-ins, a Photoshop licence to run.

How to judge the result

On a screen proof, look for banding in gradients, a highlight white that has crept into midtones, and an underbase edge visible past the color plates. Then stop looking at the screen. Simulated process is judged on a printed test — inks and mesh and squeegee pressure change the answer, and the first print on a new setup is where your density adjustment here, and any finer downstream tone curves, come from. Record the settings for the ink set you actually run; the workspace does not yet save a press preset for the next session.