page fifty-six

The Plate

Yesterday you stood still at the post while the dog did the moving. Today somebody else has to keep still. A portrait studio under a glass roof, some time between 1854 and 1880: coat a glass with collodion, sensitise it in silver, and expose it by nothing but your own judgement of the sky, counting seconds while the sitter tries not to breathe. Then develop it before it dries, and find out whether they will pay for it.

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The roof · light on the sitter| the book's sky
Now—
Studio clock—
The sitter—
The sky—
Stop—
Plates—
In the bath—
The plate—

The light is the sky through the roof: the sun's height today, the town's smoke and the clouds going over. The plate takes it in only while the lens is open, so a cloud in the middle of an exposure costs you light you cannot see on the counter. Each stop down needs the time shown against it but sharpens the hands, the figure and the background. The sitter sways a little more with every second held.

Day
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Every day is a different year, town, sky, darkroom and sitter.

What is real here and what is not

The process, its order and its troubles are real. The studio, the operator and the sitters are the day's number; the light and the chemistry are a model, sized to give the right sort of seconds.

  1. 01

    Wet plate

    Frederick Scott Archer published the collodion process in 1851 and did not patent it. A glass is coated with collodion carrying iodide and bromide salts, dipped in a bath of silver nitrate, exposed while still wet, developed with iron sulphate and fixed, all inside ten minutes or so, because once the plate dries it loses its speed and stains. A thin, slightly under-exposed negative backed with black varnish or velvet reads as a positive: that is the ambrotype, sold cased in thousands of high street glasshouses for a shilling or two.

  2. 02

    Blue light only

    Collodion is sensitive to blue, violet and ultraviolet light and nearly blind to red and yellow. Red coats and gold chains come out black, blue silk and blue eyes come out pale, freckles show and lips darken. Studios were glasshouses on top floors, often with blue glass and blinds, and an operator learned the light by eye: the season, the hour, the cloud, and in a town the smoke.

  3. 03

    Keeping still

    Exposures ran from a couple of seconds under a bright summer sky to half a minute or more in winter, and every studio had an iron head-rest behind the chair. Small children were held by a mother hidden behind a cloth. Portrait lenses on Petzval's 1840 design were fast but sharp only in the middle; a smaller Waterhouse stop sharpened the edges of the picture at the price of a longer sitting.

  4. 04

    What the page simplifies

    The light is one number for the whole studio, the sitter sways as a single piece and the focus is set for you on the eyes. The book's rule (three seconds at f/3.6 under a bright midsummer noon sky, the bath fresh, the room at 62°F, double for every eighteen degrees colder) is the page's own calibration, not a recipe. The plate's tones, the fog from over-development, the dried edges and the streaks from a plate lifted from the bath too soon are worked out by a model, and the studio clock runs eight times as fast as yours except while the lens is open and the developer is on.

Fifty-six rooms, and one number doing all the work. Today it seats somebody in a chair under a glass roof and decides which clouds go over while they try to keep still.