Solarisation

Solarisation flips part of the tone range while the film or the print is still in the developer. The result is neither a positive nor a negative. It is both at once, and the eye cannot settle on which it is looking at.

The signature is the Mackie line: a thin light outline that traces every edge where a dark area meets a light one. That line is the one thing that separates a real solarisation from a picture inverted on a computer.

Name the Sabattier effect as well as solarisation. The word solarisation on its own pulls up a plain inversion. Say the film or the print takes a second, brief exposure to light part way through development.

Say which way the tones travel. The highlights reverse to grey or to black and the shadows mostly hold, so contrast collapses through the middle of the range and the separation of tone goes with it. Ask for partial reversal, never full.

Ask for the Mackie line by name and describe it: a thin bright outline along every boundary between dark and light. Then say the grain is heavy and the development is uneven. On a colour original, say the colour goes muddy and no clean hue is left.

Use it for a record sleeve, a poster, a title card, or a portrait that is meant to unsettle somebody. It suits any picture that can lose its detail and still work as a shape.

Leave it alone when the subject has to stay readable. Solarisation destroys texture and mid tone, and a face often stops looking like a person at all.

A plain inversion flips every tone by the same amount and leaves clean edges behind. Solarisation reverses part of the range only, and it always leaves the Mackie line.

Cinema publishes Overexposed as its own entry at /techniques/cinema/. That entry is too much light on the way into the camera. Solarisation is light let in part way through development, and the two look nothing alike.

A lith print also raises contrast and coarsens the grain, but it keeps the order of the tones intact. Solarisation breaks that order, which is the whole point of it.

Man Ray and Lee Miller found the effect in a Paris darkroom in 1929, when Miller turned the light on with film still in the tray, and the studio printed the results through the 1930s. The look reached the public on record sleeves and fashion pages in the late 1960s and the 1970s, where a solarised portrait was the fastest way to make a picture look modern.

The model returns a straight negative of the picture. Say partial reversal, say the shadows hold while the highlights flip, and ask for the Mackie line along every edge.

The other failure is a clean inversion that looks made on a computer. Ask for silver gelatin paper, heavy grain and uneven development marks across the sheet.