Cross processing is when you deliberately process a film using the chemicals intended for a different type of film. The results are unpredictable with strange colour shifts and increased contrast that gives a very distinctive look. Fortunately, with digital capture we have much more control and creative freedom over the output.
This technique works by manipulating the brightness and contrast for each of the three colour channels (red, green and blue) thus distorting the overall image tone.
The final look is very much down to your own taste so take time to experiment with the contrast curves you add to each colour channel. If you have found something that works but want to experiment more, just switch off your current Curves adjustment layer by clicking the eye icon. Then create an additional Curves adjustment layer and play with the values there. In this way your original settings will not be altered and you can easily create as many variations as you wish. It’s a good idea to name the layers so you don’t accidentally change your favourite one.
1 First tweak
First lighten the image up a little by adding a Levels adjustment layer. Slide the white triangle to the right-hand edge of the histogram to set the highlights. Next move the mid-point grey triangle a little to the left to add overall brightness.
2 Channel control
Now we’ll add the cross processing look with a Curves adjustment layer. By default, changes you make to the curve will affect all three colour channels. For this effect we need to make different changes to the individual red, green and blue channels. Select Red from the drop-down list above the graph.
3 Make it more red
Adjust the red curve by dragging the right-hand point along the top forcing the brightest reds to maximum brightness. Add an ‘S’ curve to the remaining line to add more contrast to the red channel. There is no right or wrong setting for this, so experiment to get the effect you want – and every image will be different.
4 Blue moves
Now select the blue channel from the drop-down list. We’re going to constrain the Blue values by moving the right-hand point down the right-hand axis and moving the left-hand point up the left-hand axis. This clips the blue highlights and shadows to a restricted mid-tone. As before, experiment with this setting.
5 The Greener side
Finally, select the green channel from the drop-down list. Just apply a fairly gentle ‘S’ curve to this channel, slightly increasing the Green channel contrast. The basic cross processing effect should now be visible. Click the Curves adjustment layer eye icon to see before and after views.
6 Final step: fade away
Cross processed images often have a faded, low contrast look. To add this create a Solid Color adjustment layer. This is only available by clicking the black and white circle icon at the bottom of the right panel; not from the adjustment layers menu. Select a yellow/green colour. Reduce the opacity to around 10% to reveal the image.
Taken from the April 2011 issue of Advanced Photographer magazine