There may be times when you want to apply different conversion methods to different parts of the image. Here’s how.
UPDATE: This tutorial uses some obsolete methods such as the hue/saturation method. I created this example about ten years ago, before Photoshop CS3 introduced black and white filters. If I were to redo this today I would use different conversion methods. However this tutorial, along with Selective Color, is a good example of how to use color selection during black and white processing. – DK
Here is the original color photo of Parliament Hill in Ottawa. For this example I’ll convert the sky using one method and the rest of the photo using another method.
Steps in Photoshop
- Select the sky using the Magic Wand tool.
- Save the selection as the Alpha channel. From the menus choose:
- In the Save Selection dialog box leave the Name field blank and click OK.
- With sky selected add a Channel Mixer layer.
- Set red channel to 125%, check monochrome, and set constant to -25%.
The image now looks like this:
Notice how when the channel mixer layer was created it also created the layer mask. This means that the channel mixer layer applies only to the selected part of the image, ie. the sky.
Now I’ll convert the ground using the hue/saturation method. Since I’m only going to apply it to the ground I’ll need to select it before adding the hue/saturation layers. I do this by reloading the saved selection.
- Reload the previous selection. From the menus choose:
- From the Channel drop-down select “Alpha 1”. Check “Invert”. This will invert the selection so that the ground will be selected.
- With the ground selected add a Hue/Saturation layer.
- Duplicate the Hue/Saturation layer.
- In the second Hue/Saturation layer set the saturation to -100%
- Select the first Hue/Saturation layer and set the blend mode to Color
- Adjust the hue in the first Hue/Saturation layer
This is what the image looks like now.
- Add a Curves layer
- Use Warm Midtones curve
Now I’ll add the s-curve
- Adjust brightness and contrast
This is the final image