What is solarisation in photography and how do you recreate it digitally?

Solarisation is a darkroom printing technique made famous by photographer Man Ray, and it involves re-exposing a print to light half way through its development time. This results in a partial reversal of the tones in the image, so that you get a mixture of a positive and negative image.

There is some debate over whether ‘solarisation’ is the proper name. Technically, it’s the Sabattier effect, but over time it’s become known as pseudo-solarisation and then the ‘pseudo’ part has been dropped.

In the darkroom it’s an easy effect to create but not so easy to repeat precisely. You expose the print under the enlarger as usual, and then while it is in the developer tray you re-expose it to light – you can switch on the main darkroom light for a brief time to do this – and then you continue with the print development as usual. How much of the image remains ‘positive’ and how much becomes ‘negative’ is all down to timing – how long you leave the print developing before you re-expose it, how dense the original negative is, the temperature and freshness of the developer and so on.

How to create a solarisation effect digitally

This is actually quite easy to achieve with a Curves adjustment. Normally the curve shape goes from bottom left to top right, but if you add a control point half way and then drag the right-hand highlight control point back down to zero you get this partial-negative effect. You can enhance it by dragging the central control point up towards the top of the scale or even by adding a second ‘peak’.

How to use the Solarisation Filter in Nik Color Efex

It’s even easier to create this solarisation effect with a filter designed specifically for the job, and that’s exactly what you get in Nik Color Efex, part of the DxO Nik Collection. This is just one of more than 50 filters you can use individually or combine for more complex effects.

So let’s take a look at how this Solarisation filter works:

• Method: This is a drop-down menu with a selection of pre-configured solarisation effects. This is one of the black and white solarisation methods, but you can create color images too.
• Saturation: You can use this slider to adjust the strength of the colors when you’re using one of the color solarisation methods.
• Elapsed time: This refers to the traditional darkroom process, where you would choose how much time should elapse in the developer before you re-expose the image. Here, it adjusts the balance between the normal ‘positive’ tones and the reversed ‘negative’ tones.
• Opacity: As with the other Color Efex filters, this simply adjusts the overall strength of the effect and is used most often when you are combining filters.

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What kind of image suits this solarisation effect?

As ever with effects filters, you need to start with an image that’s going to complement it. I’ve chosen this low-angle wide-angle shot of a trike for its reflective surfaces and chrome-plating – these always respond well to solarisation. It also has a somewhat dramatic and other-worldly composition together with a light-toned sky that reverses to a dense black (lighter areas in a solarised image reverse, darker areas keep their original tone.

You’ll see there’s some posterisation and banding in the sky towards the top left. This is because I was working from an 8-bit JPEG image. For effects which involve strong tonal adjustments, it’s often better to start from a RAW file in your host application, e.g. Lightroom Classic or Capture One, and send a 16-bit TIFF version to Color Efex.