Which historical process should I pick?

Start from the object you want in the picture. A cased plate that flips as you tilt it is the daguerreotype. A cheap bare metal portrait is the tintype. A glossy brown print on card is the albumen print. A matte, calm, expensive looking print is the platinum one. The process is the object, so choose the object first.

Do I have to describe the plate, the case and the mount?

Yes, and it is the part most prompts miss. A model will give you a modern photograph with a brown grade unless the prompt names the physical thing: the silvered plate, the cover glass, the brass mat, the card mount, the sheared metal edge or the brushed coating border. The edge of the object is as much of the look as the picture inside it.

Why does my prompt come back as a modern photo with a sepia filter?

Because the prompt named a date and nothing physical. Take the tone, the colour and the edge in turn. Say whether the tone is cool silver, creamy grey or purple brown. Say whether the surface is a mirror, a gloss or dead matte. Then say what the edge is: a case, a card, a sheared sheet or a brush mark.

Historical processes

The processes from before the film roll, and the wording for each.

Every process here is an object first and a picture second: a silvered plate, a sheet of blackened iron, a coat of pigment, a screen of dyed starch. The process decides the tone, the colour and the physical edge of the thing, so a prompt has to ask for the plate, the case, the mount and the border as well as for the subject. Ask only for the picture and a model gives you a modern photograph with a brown grade on it. Cyanotype is the one process missing from this group. It lives in the design catalogue, under print processes, because it arrived there as a print look first.

Silver on metal and glass

Four processes where the picture lives on a plate. Three of them make a single object with no negative behind it, and the fourth is the negative that printed the century.

Daguerreotype

A mirror bright silver plate that flips between a positive and a negative as you tilt it.

Wet plate collodion

A hand poured plate that streaks at the edge, goes blind to red, and leaves the sky blank white.

Ambrotype

A thin collodion negative on glass, backed with black, so it reads as a soft grey positive.

Tintype

A collodion positive on blackened iron: dark, flat, silvery, cut to size and scratched.

Printed on paper

Four ways to get a picture onto a sheet. The coating decides the gloss, the colour and how the highlights hold, and the mount decides everything else.

Albumen print

A glossy egg white print on card, warm purple brown, and yellowed at the edges.

Platinum print

Platinum held in the paper fibres: dead matte, an extremely long grey scale, no gloss anywhere.

Gum bichromate

Pigment in hardened gum: painterly, soft, grainy, and any colour you choose.

Lith print

A print pulled early from dilute lith developer: hard grainy shadows, pale peach high tones.

Without a camera, and in colour

Two outliers. One drops the lens completely, and the other brought the first practical colour nearly thirty years before Kodachrome.

Photogram

No camera at all: objects lie on the paper, so the result is a white outline on black.

Autochrome

The first practical colour: a pastel mosaic of dyed potato starch grains on glass.

Shoot one of them

Copy a prompt into an image model and pay for that one run. No subscription.

Open an image model

Other look groups

Colour film stocksThe colour stocks, and what each does to skin, to sky and to green.12 colour stocks Black and white film stocksThe stocks, and what each one does to grain, to skin and to the sky.8 black and white stocks Slide and instant filmThe positive stocks, their narrow latitude, and the wording for each.8 slide and instant stocks Camera and formatThe ways to size a frame, and the wording that gets each one.8 cameras and formats Darkroom and processThe changes made to the film itself, and the wording for each one.6 darkroom processes Photographic genresEach genre written as the lens, the light and the distance that make it.16 photographic genres Product and commercialThe shots a product needs, and the light, shadow and edge each takes.10 product shots

Cinematic techniquesShooting a video rather than a still? The same reference, for the camera in motion.

Cyanotype lives in the design catalogue, under print processes, at /techniques/styles/print-processes/cyanotype/. It arrived there as a print look first, used for engineering blueprints and for cameraless plant prints, so it is filed with the ink and press processes rather than with the photographic ones. Everything about it as a process still applies, and the two nearest entries here are the photogram and the gum bichromate print.