Recreate the layered, slightly-off-register look of Risograph printing. Ideal for posters, zines, and indie print aesthetics.
A Risograph is a duplicator, not a printer. It burns a stencil, wraps it around an ink drum, and presses soy-based ink through the stencil onto paper one colour at a time. Each additional colour means running the paper through the machine again, and paper never lands in exactly the same place twice. The misregistration, the uneven ink coverage and the way two inks overlap into a third colour are not defects to correct. They are the reason people print riso.
The mechanical constraint drives everything about riso design. The machine holds a single ink drum at a time, so a two colour print means two passes and a four colour print means four. Most riso studios stock somewhere between six and twenty drums.
This means you cannot design in RGB and hope for the best. You have to decide, before you start, which parts of the image are printed in which ink. That decision is called separation, and it is the actual craft of riso.
Riso inks are also not process inks. Fluorescent pink, federal blue, medium green, yellow, orange, teal, violet, burgundy: these are spot colours with their own personalities, and several of them are far brighter than anything CMYK can reach. Fluorescent pink in particular is genuinely fluorescent and cannot be reproduced on screen at all, which is part of why riso prints look different in the hand than in a photograph of them.
Bitgrain exports riso separations as per-ink layers, up to four inks drawn from a nine ink set, delivered as a ZIP of PNGs. Each layer is a greyscale image where black means full ink coverage and white means no ink.
That greyscale layer then gets halftoned, because riso, like every stencil process, can only put ink down or not. Riso screens are traditionally coarse, in the region of a newspaper rather than a magazine, which is why riso prints have that visible grain up close.
Where two inks overlap, they multiply. Blue over yellow gives green. Pink over blue gives a purple that neither ink can produce alone. Experienced riso designers plan for these overlaps and treat the third colour as a real part of the palette rather than an accident, which is how a two colour print ends up looking like it has five colours in it.
Total ink coverage matters. Stack too much ink in one area and the paper cannot absorb it, the sheet cockles, and the next pass smears. Keeping any single area under roughly two hundred percent combined coverage is a sensible working rule.
Paper is fed by rollers, so each pass lands somewhere within a millimetre or two of where the last one did. Fine detail that depends on two inks lining up exactly will not survive.
Work with it instead. Offset your layers deliberately by a millimetre so the drift reads as intentional. Avoid thin coloured keylines that require registration to look correct. Let flat areas of colour overlap generously rather than butting them edge to edge, because a gap between two inks is far more visible than an overlap.
Trapping, the practice of slightly expanding one colour under another, is worth applying to any element where a white gap would be obvious.
Riso is almost always printed on uncoated stock, often recycled, because soy ink needs to soak in. Uncoated paper spreads the dot, so the printed result is consistently darker and softer than the file. Designers compensate by building files a little lighter than they want the print to be.
The ink also stays slightly wet for a while and will offset onto the back of the next sheet, which is why riso studios ask you not to stack prints immediately and why heavy solid blacks are usually avoided.
Bitgrain simulates all of this on screen: the ink colours, the coarse screen, the slight misregistration, the paper texture and the way overlaps multiply. That gets you a preview you can judge. When you are ready to print for real, export the separations and hand the studio one PNG per ink, which is exactly the file format they ask for.
Technically as many as the studio has drums, but each colour is a separate pass with separate cost and separate registration drift. Two or three inks is the sweet spot, and overlapping them gives you more apparent colours than you paid for.
One greyscale or black and white file per ink, at final size and final resolution, named by ink. Bitgrain exports exactly this as a ZIP of per-ink PNG layers.
Uncoated paper absorbs ink and spreads the dot, so tones print heavier than they appear on screen. Build files roughly ten to fifteen percent lighter than the result you want.
The simulated look, yes: ink colours, coarse screen, misregistration and paper texture all render in the browser. For an actual print you still need a studio, but the separation files Bitgrain exports are what they need.