PigmentaLab

DTF semi-transparency

PigmentaLab diagnoses and fixes DTF semi-transparency with Semitransparencias Nova: it measures how much of your artwork has partial alpha, classifies each region (antialias edge, cutout haze, gradient, flat veil or ink thinner than the minimum dot) and applies the right treatment to each one, instead of one blanket threshold for everything.

DTF cannot print a pixel at 40%: every ink drop is opaque. When artwork carries partial alpha, two things happen: the RIP lays white underbase beneath those pixels and you get the pastel-sticker effect, or so little ink lands that the adhesive powder never grabs and that area fails to transfer. Semitransparencias Nova measures alpha and derives every measurement to real millimetres, separates the five situations that get mixed in one file and offers the right treatment for each: keep the antialias edge, clean the cutout haze, solidify (compositing over the garment colour) or screen the gradient into 100% opaque dots. The diagnosis and the four treatments run entirely in your browser: no credits, no signup, and the image is never uploaded to a server.

How to fix semi-transparency for DTF

Upload your PNG to the Semi-transparency tool. It accepts PNG, JPG and WebP up to 200 MB, or your whole gang sheet: up to 32,000 pixels per side and 268 megapixels. The diagnosis runs on a capped version so the canvas stays fluid, and the final file is generated separately, at the original's native resolution.
Declare the real print width in centimetres. It is the only input that lets the tool state in millimetres whether something will transfer; if the PNG carries DPI, it is proposed automatically.
Read the diagnosis: what percentage of the artwork is semi-transparent, how much falls below 50% opacity, and how many ink islands sit under the 0.5 mm minimum dot.
Check the per-region classification. Antialias edges are kept; cutout haze is cleaned; gradients and shadows are screened; a flat veil is solidified by compositing over the garment.
Pick the garment colour if you are going to solidify: the tool composites RGB = alpha·art + (1−alpha)·garment, so the print looks like it did on screen over that fabric.
To screen, pick the fineness with the LPI slider (8 to 70, defaulting to 30), the dot shape —circle, square, diamond or line— and the angle (0 to 90°, defaulting to 22.5°). The LPI is computed against your declared width and the antialias edge is protected so the contour does not come out ragged.
Export. Everything is free: the file is generated in your browser at the original's native resolution, with the DPI re-stamped so it measures exactly the same. No credits and no signup.

Specs

Transfer threshold: alpha 128 (50% de opacidad) · por debajo, el adhesivo puede no agarrar
Minimum transferable dot: 0,5 mm de diámetro · medido sobre el ancho de impresión declarado
Detected types: borde de antialias · humo de recorte · degradé / sombra · velo plano · tinta más fina que el punto mínimo
Body criterion: erosión de radio 2 px · un antialias de 1-2 px no sobrevive, un degradé sí
Screen presets: LPI de 8 a 70 (30 por defecto) · 4 formas de punto · ángulo de 0 a 90° (22,5° por defecto)
Garment compositing: RGB = alpha·arte + (1−alpha)·prenda · alpha final 255
Cost: gratis · corre entero en el navegador · sin créditos, sin registro y sin subir la imagen

Frequently asked questions

Why is semi-transparency a problem in DTF?

Because DTF cannot print a pixel at 40%: every ink drop is opaque. When the file carries partial alpha, the RIP lays proportional white underbase beneath those pixels and the pastel-sticker effect shows up, or so little ink lands that the adhesive powder has no surface to grip and that area fails to transfer when washed or when the film is peeled.

At what opacity does the transfer start to fail?

The industry reference is 50% opacity, that is alpha 128. Below that, the amount of ink laid down starts to be insufficient for the adhesive powder to grip reliably. Semitransparencias Nova shows you exactly what percentage of your artwork falls under that threshold instead of leaving it to guesswork.

Should I just binarise all alpha with Threshold 128 like the tutorials teach?

Only if your artwork has no real gradients. That method, widely taught with Photopea and Photoshop, turns any opacity ramp into a solid blob: a shadow or a fade stops being a gradient and becomes a block. It works for a cutout with haze; it ruins artwork with a gradient. That is why Semitransparencias Nova classifies first and treats second.

So how do you print a gradient in DTF?

By screening it. Instead of printing a surface at 20% opacity, you print 20% of the area at 100%: fully opaque dots spaced apart that the eye integrates as a smooth transition at normal viewing distance. Each dot gets full ink and full white underbase, so the powder grips and transfers. It is the same logic screen printing has always used.

What LPI works best for DTF?

The recommended range for DTF is 25 to 35 LPI. Below 25 the dot becomes very visible; above 35 the dot shrinks toward the minimum the adhesive powder can hold. Semitransparencias Nova delivers the LPI against the real print width you declare, so the same preset means the same thing on a small sheet and on a 60 cm one.

Should the antialias edge of a cutout be screened too?

No, and it is better not to. The antialias band of a cutout is 1 or 2 pixels, which at 300 dpi is between 0.08 and 0.17 mm: it produces no haze and it is what keeps the contour smooth. Screening it leaves the edge ragged. Semitransparencias Nova detects it by erosion (a thin band does not survive a radius-2 erosion, a gradient does) and resolves it by threshold instead of dots.

What does compositing over the garment colour mean?

It means resolving the blend the semi-transparency was going to produce over the fabric and baking it into the file: RGB = alpha·art + (1−alpha)·garment, with final alpha at 255. The result is 100% opaque, so DTF can print it, and over that garment it looks exactly like it did on screen. The trade-off is that it is tied to that fabric colour.

Why does a halftone look duller than the solid colour?

Because of area coverage, not a colour change. The eye integrates dot and fabric in linear space (Murray-Davies law), so a screened red over white fabric reads paler than the same red at full ink. The engine does not alter your artwork's RGB. Compensating for that per zone over dark fabric is a decision that lives in Zone Halftone.

How much does it cost?

Nothing. No credits and no signup: the engine runs entirely in your browser, the image is never uploaded to a server, and the download comes out at your file's native resolution with its DPI. This is the complete tool, not a trial version. The only thing that lives in another tool is the per-zone decision, which is Zone Halftone.

Explore key pages

https://pigmentalab.io/en/semitransparencias-dtf