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DTF: RGB or CMYK, 300 DPI, transparent background.

DTF in RGB or CMYK? 300 DPI at print size, a true transparent PNG, strokes and gaps of 2 pt: what DTF makers, RIPs and shops ask, and where they split.

Sources read 2026-10-19 · updated 2026-10-26 · next re-read due 2027-01-17

On this page

How the process treats your file

A DTF printer lays the colour layers on PET film first and the white layer over them, in reverse of the order the garment will show (Printify). The RIP splits the artwork into CMYK and a white layer and works out which pixels to skip so the film stays clear. That makes the alpha channel the instruction for where ink and white go.

Every seller-facing guide read asks for a true transparent background, and most name PNG first; four of them also accept JPG, which cannot carry one. The RIPs read that transparency to build the white layer. The two RIP pages behind that statement are CADlink Digital Factory’s general queue help and a FlexiPRINT how-to from distributor Amaya UK; neither page is DTF-specific (CADlink, Amaya UK).

The numbers are where shops part. Resolution floors run from 150 DPI (Transfer Kingdom, Exclaim) to 300 DPI (Printify, Transfer Superstars, t-shirt.ca, and Printful’s current help centre for DTFlex). Colour mode splits two ways: upload RGB and let the shop convert, or convert to CMYK yourself.

What the printers specify

Gang-sheet shops print 22 inches wide by default (Ninja Transfers, DTF Transfers Now); platforms set the area per product template.

Resolution at print size

Four platforms and Printful’s current help ask for 300 DPI at final size (Transfer Superstars); two accept 150 (Transfer Kingdom). If you do not know the printer, build at 300 DPI at 1:1. The maker figures below are output resolution, not file floors.

File format

PNG is what the platforms ask for first; Roland’s and Mimaki’s RIPs also list PDF, EPS and PS, Epson’s lists raster formats only. JPG has no alpha channel, and in DTF the alpha channel decides where white goes.

Colour mode and profile

Most sources want RGB, with sRGB named where a profile is named; two shops want CMYK. Without a shop rule, send sRGB.

Transparency and alpha

Every shop page that addresses opacity wants pixels fully opaque or fully transparent; DTF Transfers Now, Ninja and Exclaim do not address it. No RIP page read states its default for the pixels in between.

White handling

No shop page read asks the seller for a white layer; the RIP builds it from the alpha channel and pulls it in a pixel or two from the colour edge.

UV-DTF transfers choke the white the same way and add a varnish layer printed slightly larger than the art: see UV flatbed and UV-DTF: UV-DTF film.

Minimum line and text size

The strictest rule read is 2 pt for strokes and for gaps (Transfer Kingdom). Build to that and the file passes the line rules of all four shops.

Bleed and safe zone

DTF has no trim bleed in the offset sense: the transfer is cut to the design, and the white must stay inside the colour edge (see the choke above).

Ink limits and gradients

Ink limits are RIP settings. The seller controls gradients, and no source allows a fade to transparent.

Gang sheets: width, spacing, scaling, mirroring

Build the sheet at the shop’s exact width, unmirrored, with space between designs.

Large solid areas and halftones

No source gives an area limit. All agree big solid blocks feel heavy and a halftone lightens them.

Where the sources disagree

DTF in RGB or CMYK: upload RGB, or convert to CMYK first

DTF Transfers Now says send RGB, because “converting to CMYK first tends to dull the brightest colors” (DTF Transfers Now); Printful and Epson name sRGB (Printful, Epson). Transfer Superstars says convert to CMYK with FOGRA39 before submitting (Transfer Superstars). Transfer Kingdom requires CMYK but auto-converts RGB, so in practice it accepts both (Transfer Kingdom).

On the floor: the same file prints differently in the two camps. Ask before converting.

DTF 300 DPI or 150: the resolution floor

Transfer Superstars calls 300 DPI at final size “the minimum” (Transfer Superstars). Transfer Kingdom accepts “150 – 900 dpi” (Transfer Kingdom) and Exclaim asks for at least 150 DPI at print size (Exclaim). Printful’s 2024 blog said 150–300 (Printful blog); its help centre, updated 2026-09-30, says 300 for DTFlex (Printful help).

On the floor: a 150 DPI file passes two shops and fails the stated minimum elsewhere. Guides citing Printful at 150 for DTFlex are quoting the 2024 blog; Printful’s general file help, updated 2026-10-15, still says 150–300 depending on product (Printful help), and only the DTFlex line says 300.

Semi-transparent pixels: full white or graded white

Printify says every pixel that is not fully transparent gets white (Printify). CADlink Digital Factory’s general queue help offers both behaviours as options: Adaptive scales white by opacity, “Treat all semi-transparent as opaque” does not; the default is not stated (CADlink).

On the floor: the seller cannot see which one a shop runs, so remove partial alpha.

DTG printers split on the same question: see DTG: Semi-transparent pixels.

Minimum line: 1 pt, 0.5 mm, 6 px or 2 pt

Printful’s floor is 1 pt, about 0.353 mm (Printful). t-shirt.ca asks for 0.5 mm (t-shirt.ca), Transfer Superstars 6 px, which is 0.508 mm at 300 DPI (Transfer Superstars), and Transfer Kingdom 2 pt, 0.706 mm, for lines and gaps (Transfer Kingdom).

On the floor: a hairline that passes Printful’s 1 pt rule is below the minimum at all three other shops.

Who sets the sheet

DTF Transfers Now: “We do not resize, move or rearrange anything”, and “Anything wider than the sheet gets cut off” (DTF Transfers Now). Ninja: “Your design isn’t stretched; it’s only scaled to fit the roll width” (Ninja Transfers).

On the floor: a sheet at the wrong width is rescaled at one shop and cropped at the other.

Is JPG acceptable

Transfer Superstars: “JPG is accepted but it’s the last resort”, warning of “a white background baked into the transfer” (Transfer Superstars). Printify: “No JPEGs, ever” (Printify).

On the floor: both agree on the result. A JPG has no alpha, so the background prints.

What fails on the floor

No case below comes with a photo or the file’s properties; all are text descriptions.

White box around the design

Watch the explainer (5 min)

Symptom: a printed white rectangle around the artwork. Cause in the file: a white or solid background instead of transparency. “DTF prints white ink, so that white box gets printed around your artwork” (DTF Transfers Now).

The same failure on a garment printed direct: DTG: White box printed around the whole design.

Faint box or halo after pressing

Watch the explainer (5 min)

Symptom: the design looked clean on screen and presses with a faint box or halo. Cause in the file: background hidden rather than deleted, or artwork on a white canvas; stray or semi-transparent edge pixels survive export (DTF Sheet: DTF transfer artwork requirements). Kolormatrix lists white halo, dark outline from the old background and powder sticking around the design as common problems (Kolormatrix: DTF artwork preparation guide).

Stiff patches and white borders from a shadow

Symptom: “stiff, rubbery patches on the fabric, and unwanted white borders around your art”. Cause in the file: a white background, or a soft drop shadow or feathered glow, left in the alpha channel (Printify).

Soft edges print rough and blotchy

Symptom: a rough, blotchy edge. Cause in the file: soft edges built from small dots too small to adhere to the garment (Printful).

Small dots and thin lines peel

Symptom: details peel, lift or go missing, and wash durability drops. Cause in the file: strokes and dots too thin to carry enough adhesive (Printful, t-shirt.ca).

Small text lifts

Symptom: small lettering peels. Cause in the file: text below the stated size. Printful’s own mitigation is a background colour behind small text; this is advice, not a photographed failure (Printful).

White underbase visible outside the colour edge

Symptom: white shows past the image on film. Cause: in the job setup, not the file. Epson’s first checks are the correct side of the sheet and a job set for film, then “increase the Reduce White Area setting in Garment Creator 2” (Epson). CADlink’s choke exists to prevent the underbase “peeking out” (CADlink).

What shops ask on the forums

Four file questions came up in at least two threads since 2024. The quotes are the askers’ opening posts; replies are not used, and not every asker names DTF.

“The customer’s art is low-resolution. How do I get it to print size?”

“I have this issue, where the DPI falls below 200, easily.” — Forum: DPI issue, May 2026. The asker exports a background-less PNG for a T-shirt and asks DTF or DTG. Also asked in Forum: Poor Quality AI Art from Customers, March 2026, Forum: Today, ChatGPT introduced Images 2.0, Print Ready?, April 2026 and Forum: Question about DPI, November 2025.

What our sources say: 300 DPI at final size (Transfer Superstars), 150 at Transfer Kingdom and Exclaim, and “A 300 DPI file scaled up to double its size is really a 150 DPI file” (DTF Transfers Now), so pixels at print size count, not the tag. None says what to do when the pixels are not there: upscale, redraw as vector or print smaller.

“How do I get a clean transparent background out of Canva or a photo?”

“the file still saves with a white background” — Forum: Canva Transparency, April 2025, a white text design for a T-shirt with transparent export ticked. Also asked in Forum: Best inexpensive editor for modifying images for DTF, October 2026 and Forum: Anyone here successfully print a transparent crop from a photo?, March 2024.

What our sources say: the end state and one method, a background deleted rather than hidden and no white canvas under the art (DTF Sheet; see also Printify and DTF Transfers Now). None covers the export step in Canva, a tool for cut-outs, or soft edges such as hair, fur or smoke that a hard cut-out cannot hold.

“Why do the printed colours not match the screen, and what colour mode should I send?”

“I cannot get a true print that matches the art on the screen.” — Forum: Tricks for converting RGB to CMYK and getting true to colour output, March 2025, on the DTF board. Also asked in Forum: Acorip Software / Photoshop color settings, May 2025 and Forum: Safety Green, Printing the color Safety Green as close as possible., September 2026, where the asker wants Safety Green on black garments and will test a transfer.

What our sources say: the split above, sRGB at Printful, Printify and Epson, RGB at DTF Transfers Now, CMYK FOGRA39 at Transfer Superstars, CMYK required but auto-converted at Transfer Kingdom. None explains why the print still differs once the right mode is sent, or gives CMYK values for a colour.

“Why did a grainy border around my design transfer onto the shirt?”

“the grainy, bluish border that was around the design seemed to have transferred onto the shirt as well” — Forum: How do fix this?, July 2024. The asker ordered a DTF transfer and names no cause; a reply suggests semi-transparent pixels in the PNG. Also asked in Forum: Antialiased vs aliased, May 2026, whose asker wants to know whether anti-aliased edge pixels show in print. Older threads ask the same: Forum: DTF Visible “transparent” dots underneath design, December 2023, Forum: question about white outline on DTF prints, January 2023, Forum: How to print photos with faded edges on a black tee using DTG or DTF, May 2023.

What our sources say: “The machine reads any pixel that isn’t transparent as ink it needs to lay down” (Printify); anti-aliased pixels appear only in CADlink’s Valid Pixel Tolerance option, not as a seller rule (CADlink); ColDesi starts halftones at 40 LPI (ColDesi). None says how to find partial alpha you cannot see, or which halftone LPI a given shop wants.

Preflight before you upload

  • Canvas matches the product template or the shop’s sheet width (22, 24 or 30 in) exactly — DTF Transfers Now
  • Image is 300 DPI at the final print size, checked after any scaling — Printful help, DTF Transfers Now
  • File is PNG with a real alpha channel, not JPG — Printify
  • Background layer deleted, not hidden; no white canvas under the art — DTF Sheet
  • No pixel with partial opacity: inspect the alpha at the edges and in shadows — Transfer Superstars
  • Shadows and glows are hard-edged and fully opaque, or halftoned — Transfer Superstars, Printful
  • No gradient fades to transparent — Printful blog
  • Colour mode matches the shop: sRGB unless the shop asks for CMYK FOGRA39 — Transfer Superstars
  • Every stroke and every gap is at least 2 pt (0.706 mm) — Transfer Kingdom
  • Text is 10 pt or larger; small text sits on a background colour — Printful
  • Canvas cropped to the design, bleed 2 mm at most — Transfer Superstars
  • Gang sheet: at least a quarter inch between designs — DTF Transfers Now
  • Artwork in normal reading direction, not mirrored — t-shirt.ca
  • Large solid areas on thin fabric broken up with see-through elements — Printful blog

Sources, checked on 2026-10-19

Forum threads

Could not check

  • gelato.com DTF blog and article pages: blocked to the fetcher and a browser user agent; only the apparel-wide support article was read.
  • equipmentzone.com Garment Creator DTF PDF: 403.
  • CADlink DTF Edition brochure on marketing.cadlink.com: unreadable; the CADlink behaviour above is from the general Digital Factory help.
  • mimakiusa.com spec sheet and TxF300-75 PDF: unreadable; the TxF150-75 brochure was read instead.
  • Ninja Transfers halftone page and fontbundles.net: unreadable.
  • Roland BN-20D white-assignment PDFs and Epson’s DTF Film Printing Guide: not opened or not found.
  • AcroRIP, NeoStampa, Prestige/STS, Brother: no official page read on how they treat partial alpha or resolution.

Verdicts on claims in this guide

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