Color Separation for 4-Color DTG Printing
Direct-to-garment (DTG) printing applies CMYK ink directly onto fabric — no screens, no setup, no minimum order quantity. But the color separation workflow is different from screen printing. DTG uses 4-color process (CMYK) with a white underbase for dark fabrics, and the RIP handles most of the heavy lifting. This tutorial covers the separation workflow, RIP setup, and pre-treatment requirements for vivid prints on both light and dark substrates.
Step-by-Step Guide
Understand the 4-color CMYK + white underbase model
DTG printers (Brother, Epson, Kornit, Roland) lay down CMYK ink on the fabric surface. On white or light fabric, CMYK alone produces vivid color. On dark fabric, CMYK ink is transparent and disappears — so DTG prints a white underbase first, then layers CMYK on top. The underbase adds 30-50% to ink cost and slows printing by ~2x, but it's the only way to achieve vivid color on black or navy fabric.
- Light fabric = CMYK only
- Dark fabric = white underbase + CMYK
- Underbase doubles ink cost and time
Prepare the artwork at production resolution
DTG resolution is typically 1200 × 1200 DPI native. Export your design at 300 DPI minimum (DTG RIPs handle resampling fine, but starting at 300+ avoids visible pixelation). Use sRGB color profile — DTG manufacturers calibrate their RIPs to sRGB by default. AdobeRGB designs need conversion at the RIP stage and may produce unexpected color shifts.
- 300 DPI minimum, 600 DPI ideal
- sRGB is the DTG default
- AdobeRGB needs RIP conversion
Separate transparency for the white underbase
DTG RIPs auto-generate the white underbase from the design's alpha channel — every non-transparent pixel gets white ink underneath. For complex designs with semi-transparent elements (gradients to transparent, soft edges), the auto-generated underbase may be wrong. Manually edit the alpha channel or create an explicit underbase layer to control where white prints.
- Alpha channel drives the auto-underbase
- Semi-transparent areas need manual underbase
- White underbase = print-on-dark visibility
Configure the RIP for fabric base
DTG RIPs (Wasatch SoftRIP, Kothari Print Pro, Cadlink Digital Factory) have presets per fabric base — cotton-100, polyester-100, blends, etc. Pick the preset matching the garment substrate. The preset adjusts ink density (more for absorbent cotton, less for non-absorbent polyester), curing temperature, and pre-treatment timing.
- RIP preset per fabric base
- Cotton needs more ink than polyester
- Poly blends need careful pre-treatment
Apply pre-treatment to dark fabric
Dark cotton needs pre-treatment liquid (Brother PT, Epson G2-T, etc.) sprayed on the print area before the white underbase prints. Pre-treatment chemically prepares the fabric to accept white ink without bleeding. Apply with a HVLP sprayer at 30-50 ml per shirt, then heat-press at 165°C for 60 seconds to dry. Skipping pre-treatment produces dull, bleeding prints.
- Pre-treatment is mandatory for dark fabric
- 30-50ml per shirt, heat-pressed dry
- Skipping = dull, bleeding output
Print, cure, and quality-check
Print the design (white underbase pass + CMYK pass for dark; CMYK only for light). Cure with a heat press at 165°C for 60-90 seconds, or a tunnel dryer at 320°F for 90 seconds. Inspect cured prints under D65 daylight illuminant — DTG colors can shift visibly under different lighting due to fluorescent brighteners in the cotton.
- 165°C / 60-90s heat press
- D65 daylight for color inspection
- Cure under-cure is the most common failure
Common Mistakes to Avoid
Generate DTG-ready CMYK separations with white underbase from any design.
Open Separation Studio and skip the manual workflow.
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