My first attempts at scanning cross-processed negatives with my cheap flatbed scanner were plagued by a strange yellow color cast. (By “cross-processed,” I mean E6 slide film processed in regular C41 print chemicals.) The yellow color cast was an interesting effect, but the colors weren’t even close to those in the prints. I tried using the Levels tool in Photoshop to adjust the white balance, but it just didn’t work. After thinking about it for a while, I came up with a solution.

First attempt

Better scan

The trick I discovered is to set my scanner to Positive mode (usually used for slides), even though the image I want is negative. After scanning the image, I invert it. Then, I use the Levels tool, sometimes hitting Auto Levels and sometimes doing it manually, to get the exposure I want. I also adjust the white balance sometimes; in this case, I clicked on the white minivan to get the colors as neutral as possible. Since it’s cross-processed, the colors still look funky.

This technique seemed counterintuitive at first because inverting an image twice yields the image you started with. However, this is not the same as inverting an image twice.

In regular color negatives, the film has an orange mask, and my scanner compensates for the orange mask when set to Negative scanning mode. Cross-processing slide film leads to a negative image, but without the orange mask. So, in Negative mode, my scanner was attempting to compensate for a non-existent orange mask. Setting the scanner to Positive bypasses the mask compensation, giving accurate colors — you just have to invert the image.

A couple more examples:

File under: Geek, Photography