Using Curves to Give you a Cross-Processed Look

October 20, 2010
f/4.0; 50mm; 1/100sec; ISO 400

f/4.0; 50mm; 1/100sec; ISO 400

I know there are Cross-Processing filters available for Gimp and Photoshop, but sometimes I just prefer the simple method of adjusting my curves to give it that Cross-Processed look.

To show you what I’m talking about, here’s the photo I’m starting with – all I’ve done is converted it from RAW using UFRaw (upped the saturation during the process), and opened it up in Gimp:

Original Photo

Original Photo

Now, let’s edit it!

Getting Started

As always, the first thing I do when editing my photos is create a duplicate layer. The second thing I usual do is adjust the levels. All I did was move the left slider to the right a bit:

Levels

And that gives me this, which I really consider my “starting point” for editing:

With Adjusted Levels

With Adjusted Levels

Now, let’s play with the Curves to give it a Cross-Processed look!

Adjusting Curves

I’ve talked about adjusting the Curves when editing photos a number of times (with this post probably having the most examples), but up until this point, I’ve only ever talked about the Value channel, which lets you adjust the tonal value of each point in your photo – basically how light or dark certain parts of your photo are. But did you also know there are other chanels? Red, Green and Blue to be exact! And this is a way to make certain pixels in your photo more or less Red, Green or Blue.

Let’s take a look at at this particular curve for the Green channel (also, I cricled the channel drop-down in case you hadn’t noticed it before):

Green Curves

Green Curves

See the Black-to-white bar across the bottom? And the black to Green along the y-Axis? Think of the black to white as the “before” and the green bar as the “after”. At the left side of the curve, I have moved the curve below the line – so basically I’m saying for my darker pixels (x-axis is at the black end), I want them to have less green in them than they did before (y-axis is closer to black than pure green). On the right hand side of my curve I have moved my curve above the line – so I want my lighter pixels to have more green in them (x-axis is closer to white, y-axis is closer to pure green). Here’s what my Leaf looks like now:

After the Green Curves shown above

After the Green Curves shown above

Notice that the leaf itself (which was one of the lighter parts of the photo) has more of a green tint to it, while the fence behind it – the darkest part of the photo – is more red (because there’s less green in it now).

Whether you understand all of that or not, I’m still going to show you one of my favorite combinations of Red, Green and Blue curves. First, set your Green curve like what I have above (it doesn’t have to be exact, just make a slight S-shaped curve like that). Change your Red curve to look like this:

Red Curves

Red Curves

Now make your Blue curve look like this:

Blue Curves

Blue Curves

And that combination is what I call my Cross-Processed combination. This is what my photo looks like after applying all of that:

Cross Processed

Cross Processed

Now, the important step! You can save those curves settings so you don’t need to look up this entry the next time you want to duplicate this Cross-Processed effect. Just click the little + sign next to the Presets dropdown:

Save it!

Save it!

It will ask you for a name (I call mine xproc, if you care), and now you’ll have it forEVER. Actually, you won’t… because if you’re anything like me, you’ll lose it one day because even though you back up all your photos in case your computer crashes, you won’t remember to back up all your settings and preferences from Gimp, and you’ll lose all of them. Including these saved settings. You CAN back them up to a file using the little triangle next to the + sign and choose Export Settings to File.

Final Steps

No matter which method you like the best above, I’d still end with some sharpening, because this isn’t the sharpest photo ever. Even though FX-Foundry offers a bunch of different sharpening filters, I have to admit, I’m still a bit partial to the good old stand-by: the Unsharp Mask directly from Gimp itself (under Filters –> Enhance –> Unsharp Mask). My typical settings are as follows:

  • Radius: 2.0
  • Amount: 0.85
  • Threshold: 4

And that gives me this:

All Done!

All Done!

By the way, some of you may realize that I recently posted this photo on flickr but it looked slightly different. That’s because I also added a cyan and magenta layer to the photo, setting both layers to Screen mode at 10% Opacity. You can see that final image here.

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.


blog comments powered by Disqus