```markdown --- title: "Color Separation for Screen Printing: Spot Colors, CMYK, Underbase Explained" subtitle: "Technical Guide to Preparing Artwork for Multi-Color Screen Printing" category: Screen Printing tags: [Color Separation, Spot Colors, CMYK, Underbase, Screen Printing, 2026] author: Kevin Arnold publish_date: 2026-03-24 read_time: 11 min canonical: https://arnoldprints.com/blog/color-separation-screen-printing-2026 meta_title: "Color Separation Guide 2026 | Spot Colors, CMYK & Underbase - Arnold Prints" meta_description: "Color separation for screen printing explained: spot colors vs CMYK, underbase for dark garments, and how to prepare artwork for multi-color prints." ---

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What is Color Separation?

Color separation is the process of splitting a multi-color design into individual layers — one per color. Each layer becomes its own screen. That's the foundation of how screen printing works. Why it matters:

One screen per color keeps inks from mixing

Clean edges, sharp detail, accurate registration

No guesswork — every color prints exactly where it belongs

Example: A 3-color logo

Blue layer → Blue screen

Yellow layer → Yellow screen

Black layer → Black screen

Result: 3 screens, 3 setups, 3 print passes

Get the separation wrong and the whole print falls apart. Get it right and you've got something that lasts. ---

Spot Colors (Pantone)

A spot color is a pre-mixed ink matched to a specific Pantone number. No guessing. No approximating. The color you spec is the color you get. Why spot colors win:

Exact color matching via PMS numbers

Rich, vibrant, solid coverage

Consistent across every reprint — years later

Simple to separate, easy to execute

Best applications:

Logos and brand identity

Text and simple graphics

1–6 color designs

Corporate and licensed branding

The Pantone library gives you:

1,000+ solid colors

Metallic, fluorescent, and pastel options

Custom mixing for anything outside the standard range

Cost: Each spot color = 1 screen = $32 setup fee If brand accuracy matters — and it should — spot colors are the right call. ---

CMYK Process Printing

CMYK uses four ink colors — Cyan, Magenta, Yellow, and Black — to simulate the full color spectrum. Instead of solid ink coverage, it lays down thousands of tiny halftone dots that overlap and blend. Up close you see the dots. Step back and you see a photo. The upside:

Full-color and photorealistic results

Handles gradients and complex imagery

No theoretical color limit

The tradeoff:

Halftone dot pattern is visible at close range

Solid colors look less vibrant than spot inks

Requires skilled separations to execute well

Not the right tool for flat, solid color work

Best applications:

Photographic images

Complex gradients and color blends

Full-color artwork that can't be reduced to spot colors

Designs with 20+ colors where spot printing is impractical

Cost: Minimum 4 screens (C, M, Y, K) = $128 setup CMYK earns its place when the artwork demands it. For everything else, spot colors are sharper and more consistent. ---

Spot vs CMYK: When to Use Each

| Factor | Spot Colors | CMYK | |--------|-------------|------| | Color Count | 1–6 practical | 4 minimum, unlimited | | Color Accuracy | Exact (PMS match) | Approximate (converts) | | Vibrancy | High (solid ink) | Medium (dot pattern) | | Best For | Logos, text, solids | Photos, gradients | | Setup Cost | $32 × color count | $128 (4 screens) | | Skill Required | Basic separation | Advanced separation | | Consistency | Excellent across reprints | Good (may vary slightly) | The rule is simple: Spot colors for logos and brand work. CMYK for photos and complex gradients — and only when there's no other way. ---

Underbase for Dark Garments

Printing on a dark garment without an underbase is a mistake. Fabric color bleeds through the ink and kills your vibrancy — reds go purple, whites go gray. An underbase fixes that. What it does:

White ink is printed as the first layer

It blocks the garment color from affecting what's on top

Colors printed over the underbase appear full-strength and clean

The process: 1. Print white underbase first 2. Flash cure (partially dry the ink) 3. Print colors on top 4. Full cure What it costs:

Underbase counts as an additional color

A 2-color design on a dark garment = 3 screens

Setup: 3 × $32 = $96 (vs. $64 on a light garment)

Real-world example:

Navy garment, 2-color logo (red + white text)

Without underbase: Red looks purple, white looks gray

With underbase: Red is vibrant, white is crisp

If you're printing on black, navy, charcoal, or any dark color — budget for the underbase. It's not optional if you want quality results. ---

Halftones for Gradients

Screen printing lays down solid ink. It can't literally fade. Halftones solve that problem by using varying dot sizes to create the illusion of a gradient — large dots where the color is dark, smaller dots where it lightens out. Your eye blends them together. Dot shape options:

Round — the standard, works for most applications

Elliptical — smoother gradient transitions

Square — sharper, more defined transitions

Line screen (LPI):

Measured in lines per inch

85–100 LPI is standard for garment printing

Higher LPI delivers finer detail, but demands more precision to execute

Best applications:

Fade and shadow effects

Varying color intensity within a design

Gradient transitions that can't be achieved with solid spot colors

If your artwork has a gradient, it needs halftone conversion before it can be screened. Don't skip this step. ---

The Separation Process

Color separation isn't magic — it's a disciplined, step-by-step process. Here's how it works. Step 1: Artwork Analysis

Count colors, identify spot vs. CMYK requirements

Determine underbase needs based on garment color

Flag any gradients that need halftone conversion

Step 2: Color Separation

Isolate each color onto its own layer

Convert to bitmap format for screen output

Apply halftones where gradients exist

Add registration marks for alignment on press

Step 3: Film Output

Each separated layer prints to clear film — one film per color

Output at 2400+ DPI for clean, sharp edges

Films are labeled by color and print order

Step 4: Screen Exposure

Screen is coated with light-sensitive emulsion

Film is placed over the screen and exposed to UV light

Unexposed emulsion washes away, leaving the image

One screen per film, every time

Every step matters. A mistake at separation shows up on press — and on the finished garment. ---

File Setup for Separation

Send us the right files and the process moves fast. Send us the wrong ones and we're doing your job before we can do ours. Vector files (AI, EPS, PDF):

Each color on its own named layer

Layer names that match the color (e.g., "PMS 185 Red")

Pantone numbers specified

Text converted to outlines — no live fonts

Raster files (PSD, TIFF):

Each color on a separate channel

300+ DPI at final print size

CMYK or Spot color mode only

Transparency flattened before sending

Include with your files:

Total color count

Pantone numbers for any spot colors

Note if garment is dark (underbase needed)

Print order if known (light to dark)

Garment color

Do not send files with:

RGB color mode (it will shift on conversion)

Live effects like drop shadows or glows

Transparent gradients (convert to halftone first)

Unoutlined text

Set up your files correctly and you'll save time, money, and back-and-forth. ---

Separation Mistakes

These are the most common ways artwork fails — and how to avoid every one of them. ❌ RGB files RGB is for screens. Screen printing uses ink. RGB to CMYK conversion causes color shifts you won't like. Fix: Design in CMYK or Pantone from the start. ❌ Too many colors Every color is another screen, another $32 setup fee. Fix: Simplify the design. Four to six colors is the sweet spot for cost-effective screen printing. ❌ No underbase note Dark garments need an underbase. If you don't tell us, we have to assume — and assumptions cost time. Fix: Specify garment color upfront. Every time. ❌ Gradients without halftone conversion Solid ink can't fade. A gradient that hasn't been converted to halftone can't be screened. Fix: Convert all gradients to halftone before submitting. ❌ Tiny text Anything under 6pt won't hold on a screen. The emulsion can't support it. Fix: Keep text at 8pt minimum for screen printing. ❌ Hairline strokes Lines under 1pt break down in the screen and disappear in the print. Fix: Minimum 1.5pt stroke weight — no exceptions. ❌ Unseparated layers When layers aren't separated, we have to do it manually. That's an art fee on top of your setup cost. Fix: Provide separated layers. It's faster for everyone. ---

Get a Quote

Ready to print? We handle color separation in-house and we know what it takes to get your artwork right the first time. Three ways to get started:

Business Quote Form — Upload your artwork and get a fast, accurate quote

Email: sales@arnoldprints.com — Attach your files and note your garment color

Call: (561) 323-7573 — Talk directly to someone who knows screen printing

Don't sit on a design that's ready to go. Submit your artwork today and we'll tell you exactly what it'll take to get it on a shirt. Keep building your knowledge:

Screen Printing Services

Artwork Requirements

Screen Printing Explained

DTF vs Screen Printing

--- Internal Links (10+ money pages):

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/blog/dtf-complete-guide-2026 (cluster)

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/blog/artwork-guidelines-print-ready-2026 (cluster)

/blog/dtf-gang-sheet-optimization-2026 (cluster)

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