How To Make A Cyanotype Print Effect With AI
The prompt is long and most of its length is spent on one thing: keeping the deepest value in the frame out of the subject entirely. Full bleed, no paper edge.
One hex value does most of the work here. #1B3A5B, reserved for the background and used nowhere else, is what separates a cyanotype print from a photograph with a blue wash over it.
Ask a model for a cyanotype and it tends to return an object rather than an image. A ragged brushstroke edge, a strip of white paper around the frame, sometimes a shadow underneath as though the print were lying on a table. The reading is fair enough, since most cyanotypes online are photographs of prints, but it is not what you want. The prompt rules it out in the opening clause and spends the rest of its length on tone.
Every image in this post came out of it.
The prompt
Convert @Image1 into an authentic cyanotype-style image rendered edge to edge, filling the entire frame completely with no border, no paper margin, no white frame, and no brushstroke edge of any kind, the cyanotype look applied directly to the whole image as a full-bleed rendering. Preserve the exact composition, subject, pose, framing, and every fine detail of the source, and hold onto the full local contrast and tonal separation of the original so that every form, fold, edge, and material stays clearly legible after conversion. Map the image into a monochrome scale built only from Prussian blue and paper white. The brightest areas become clean paper white with a faint cool bloom, and the mid and lower tones pass down through pale, mid, and deep cyan-blue while keeping their internal detail intact. Reserve the single deepest value, a rich saturated Prussian blue at hex #1B3A5B, for the background alone, and keep the background a flat even field of that deep blue with no added scenery, objects, panels, or environment. Keep the darkest parts of the subject, including dark clothing and shadowed areas, one clear step lighter than the background in a readable mid-blue that retains fabric texture, folds, and edge definition, so the whole figure stays separated from the ground. Lift the entire silhouette with subtle tonal separation and a faint cool rim of light around its outer edge. Carry fine cotton-fibre paper grain evenly across the full frame as texture only, with gentle tonal mottling, a soft matte analog finish, softly bloomed highlights, and crisp preserved detail throughout. The result reads as a monochromatic blue sun-print rendered full-bleed: painterly, tactile, and chemical, with the full subject staying visible through contrast. Aspect ratio 4:5.
The background does the heavy lifting
Two instructions matter more than the rest. The deepest value in the frame belongs to the background alone, and that background stays a flat even field with nothing introduced into it. Drop the second one and the space fills with vignettes, spills and paper mottling that start to read as a scene.
Naming the value rather than describing it is what holds a set together. Deep Prussian blue gets interpreted a little differently on every run, so the ground shifts from image to image and the group stops looking like one body of work. A hex code does not shift.
Separating the subject from the ground
Reserving the darkest value for the background creates the obvious problem. Dark parts of the subject collapse straight into it: a black jacket, a shadowed flank, the underside of a wing. So the prompt sets a floor. The darkest parts of the subject sit one clear step lighter, in a mid-blue that still carries texture and edge definition.
The faint cool rim around the outer edge finishes the job, doing what a separation light does on a set. Without it the silhouette softens into the field on anything with a complicated outline.
What to run it on
It wants a single subject with strong texture and clean edges. The prompt preserves local contrast rather than adding any, so whatever separation exists in the source is what comes back, and a flat evenly lit photograph converts into a flat evenly lit print.
Busy backgrounds fight the flat field clause. When the source has a real environment behind the subject, the model has to choose between preserving it and flattening it, and what returns is usually a compromise that reads as neither.
The 4:5 at the end is only the ratio. Change it to whatever the piece needs.
The process dates from 1842 and it survives because it throws colour away completely and hands the entire picture over to texture. Anything with a surface gains from that. Anything without one has nowhere left to go.
