Monday, January 26, 2009

Split Grading in Photoshop and Elements

Split grading combines a high contrast image with a low contrast image for a better tonal range in a black and white photo. In other words, split grading allows you to increase contrast without losing highlight or shadow details. This quick tutorial shows you how easy it is to boost the range of a flat image. This is a fun trick to know. It is extremely easy, and although you won't need to use it on every image, it can come in handy.

A lot of tutorials will begin with a color-to-black-and-white conversion that uses the "desaturate" command. I have already shown you that the channel mixer is a far better method. I mention this because if you begin with desaturate and then use split grading the difference in the final image will be more dramatic. Here, because we begin with a better conversion, the difference is more subtle.

The Tutorial
1. Open a color image that you want to convert to black and white.
2. Change to black and white by using channel mixer as learned at the beginning of month, and flatten your image.
photos by Lucy Call

3. Now duplicate layer twice using Command-J (PC: Ctrl-J). and rename the top layer "high contrast" and the bottom layer "low contrast."
4. Deselect the "high contrast" layer by clicking the eye icon (layer visibility) in the layers palette. With the "low contrast" layer active, select Image-->Adjustments-->Brightness /Contrast from the top menu bar.


NOTE FOR ELEMENTS USERS: The only that changes with this tutorial is that you must select Enhance-->Adjust Lighting-->Brightness/Contrast as in the following screenshot:
(variation for Elements users)

In the dialog box, lower the contrast to -50 or until there is visible detail in the shadows and highlights.
(sorry, the above picture should show the slider at -50 under contrast)

5. Now you will want to make the "high contrast" layer visible (by clicking the eye icon). As long as your high contrast layer is the top layer, you will not need to deselect the bottom layer. You will repeat the steps above ( Image-->Adjustments-->Brightness /Contrast), except this time you will boost the contrast to +50.
6. With the "high contrast" (top layer) active, change the blending mode (in the layers palette) to "overlay."
7. Adjust the opacity of the top layer until you have detail in the highlights while still retaining contrast.
If your channel mixer conversion was good to begin with, your final image will have more detail in shadows and highlights. Here are the before and after images:
The "before" image (above) already has a good tonal range, but...

The "after" image shows better texture and highlights. Look at dirt around the window or at the bottom of the image. There is better overall contrast and the highlights haven't become too extreme.

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