Digital Photography Tips and Techniques

Cross processing (xpro) refers to processing film in a chemical solution intended for a different type of film (Wikipedia).

Two methods are common: processing color negative films in slide chemicals (“C-41 as E-6”), or processing slide films using the color negative chemicals (“E-6 as C-41”). Due to the characteristics of the films and chemicals, the effects are different. Processing color negative film in slide chemical tends to produce flat tones and muted colors with less red but more green/yellow while processing slide film in in color negative chemicals often produces very contrasty images with blown highlights. In either cases, we’d expect to see wild color shifts that are not quite predictable due to many factors such as film/chemical, exposure, etc, will affect the process.

Simulating the cross processing effect in photo editors are fairly easy using curves adjustments in individual color channels. For photoshop users, this is a nice tutorial on how to do the “C-41 as E-6” type cross-processing in Adobe Photoshop. For demonstration purposes, I will show you how to do the same adjustments using Nikon Capture NX2.

We start by opening a photo in Capture NX2, then open the Curves & Levels adjustment tool via  Adjust->Light->Levels & Curves menu or using keyboard shortcut Ctrl-L (Windows).

The Levels and Curves adjustment tool

Select individual Red, Green, and Blue channels and make adjustments as shown in the aforementioned Photoshop tutorial. The following screenshots show you what I got.

The red channel curve

The green channel curve

The blue channel curve

Go back to RGB channel, the curves will be shown as following. As suggested in the Photoshop tutorial, we leave the master RGB channel adjustment into a 2nd Levels & Curves adjustment.

The final curves of individual channels in Levels and Curves adjustment

As suggested, we change the opacity settings as below so the adjustments only affects the colors not the luminance. By doing so, the adjustments to color and the luminance is de-coupled, saving you some frustration going back-and-forth.

Change the opacity setting so the curves adjustments only affect color, not luminance

Add a new Levels & Curves adjustment step and adjust the RGB curve to get the desired contrast you’d like as shown below. Change the opacity setting so it only affects the luminance by dragging the Chrominance slider all the way to the left (zero).

2nd Levels and Curves adjustment only affects the luminance but not the color.

Add a Colorize adjustment step as shown below. Use the color RGB=(225, 255, 0) and change the Opacity settings as shown for the same reason mentioned earlier.

Use Colorize adjustment to add some yellow-green to the image

This is the final Edit List with all items collapsed.

The final Edit List items

Here is a before and after comparison of an example image.

Before (click to open large version)

After (Click to open large version)

I also tried the adjustment on the example photo in the Photoshop tutorial and got similar results as shown there. The effect isn’t exactly the same but that’s not important. There is no set standard on how the cross-processed photos will look like.

If you want to keep the adjustments, you can select all edit steps in the Edit List, right-click, then choose Save Adjustments. You can then run batch processing on other photos, Copy/Paste, or Load the adjustments to other photos opened in Capture NX2.

Save the adjustment for loading into other images or batch processing

For your convenience, I have attached my settings file below. Enjoy!

Download: XPRO_C41_E6_FINAL.zip