DTG on dark shirts: what to expect

Print a red logo on a white shirt and the ink goes straight down. Print the same logo on a black shirt and red ink on black fabric reads as dark brown, or as nothing much at all. Ink is not paint; it is closer to a stain.

The white underbase

So we print white first. The printer lays a layer of white ink in the exact shape of your artwork, cures it, then prints your colours on top of that white layer. Your red now has something white underneath it and reads as red.

This is standard and it works well. It also explains most of what people notice on dark garments.

Pre-treatment

White ink will not sit on raw cotton without help, so a dark garment is sprayed with a pre-treatment fluid before printing and pressed to dry. The fluid makes the fibres hold the white pigment on the surface instead of letting it sink in and disappear.

Shortly after printing you may see a faint rectangle around the design where the pre-treatment sat, which looks like a stain on an otherwise perfect shirt and is the single most common thing customers ask us about at collection. It washes out completely in the first cycle. Nothing is wrong with the shirt. On a few very dark garments the pre-treated patch is visible enough on collection that we mention it at handover, because it looks like a defect and is not.

What actually changes in the print

Colours on dark garments come out very slightly softer than the same file on white. You are looking at ink over ink rather than ink over bright cotton, and the white underbase is white, not paper-white. If you put the two shirts side by side you would see it. On its own, you would not.

The print has a little more presence on a dark shirt too, because there are two layers of ink instead of one. Not a plastic patch like heavy plastisol, but you can feel where the design is.

Designs that need a look first

A few things behave badly over a white underbase, and it is cheaper to know now than after printing.

Soft drop shadows and glows that fade to transparent are the main one. The printer has to decide where your artwork stops in order to print white in that shape, and a gradient that fades to nothing has no clear edge. The result can be a faint pale halo where the white extends past the visible colour. Either give the shadow a defined edge, or let it fade to the garment colour instead of to transparent.

Very fine light detail is the other. Hairline white text at 6pt on black is asking the printer to put down a precise sliver of white and then register colour on top of it. It will print, but it will not be crisp. Thicken it.

Pure black elements in artwork destined for a black shirt are worth deleting rather than printing — let the garment be the black. Printing black ink over white ink over black cotton to achieve black is three steps to arrive where you started, and the patch will be visible from the side.

Which garments take it best

100% ring-spun cotton, every time. Our Next Level 3600 and the Comfort Colors garment-dyed tees both take dark printing well. Heavier fabrics are more forgiving than light ones, because there is more cotton for the pre-treatment to grip.

50/50 blends on dark are the hardest case. The polyester does not hold the pre-treatment as well as cotton, and polyester dye can migrate into the white underbase during curing, which turns white ink faintly pink or grey on a red or navy garment. We can print them. We will tell you if we think a different blank would serve you better.

Washing

Same advice as any DTG print, slightly more important here because there is more ink in play. Inside out, cold, mild detergent, no bleach, hang to dry or tumble on low. The washing guide has the detail.

The blanks guide says which garments take dark printing best, and the design guide has the edge rules in full.

Send the file and the garment colour together if you are unsure. We look at dark artwork before it goes to the printer anyway, and if something in it will not survive the underbase we call rather than print it and hope.