Cross processing (also called x-pro) is an experimental form of photography where one kind of film stock is deliberately processed in chemicals intended for another kind of film. The resulting color schemes are weird and unnatural, offering traditional painters some interesting inspiration.
Here, slide film has been processed in C-41 print film chemicals. The result is a high contrast image, with a hue shift toward greens and yellows and a boost in saturation. There's also a considerable amount of vignetting at the edges, a result of the lens.
When negative film is processed in slide chemicals, the results can go many different ways, but this one is lo-fi, contrasty, and grainy, with a saturated warm color bleaching and infusing all the lights.
With X-pro, you never know how it's going to turn out. This one gets contrasty, with a green-red split in the midtones.
The colors aren't always saturated. Sometimes they're relatively muted, but still with the high contrast and the hue shift.
In this link the photographer describes the process he used.
If you want to check out more examples, check out any of these galleries:
Epic Edits: Ten Reasons to Love Cross Processed Film
The Darkroom: Cross Processing examples
The effect can also be simulated digitally with
filters in Instagram in or with Photoshop. Here's a
link to a Photoshop tutorial.
How can we use this as artists?
Traditional painters can use cross-processing as a jumping off point for exploring color schemes. One way is to use a strongly colored underpainting. The second example in this post of the guy riding the bike could be painted over an orange base color, leaving that color as the stand-in for all the light values. The scheme in the lower scene of the little kid on the Harley could be simulated with a green-red-yellow limited palette, taking care to bleach the lights, sink the darks, and vignette the edges.
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