Gradient Maps are one of those adjustments in Photoshop that people feel they couldn’t use for any useful purpose with their images.
So what do gradient maps do ….. they allow you to assign different colours to the tonal values of an image. When you open a gradient map adjustment layer, it will default to the colours you have set as your f/ground and b/ground. Go ahead and use the image below to practise on if you like.
Set your f/ground to black and your b/ground to white, duplicate the layer and then, using the adjustment layer icon at the bottom of the layers palette, click on gradient map. You can do a comparison with how the gradient mapped image (now B&W) compares if you had simply desaturated the original image.
The gradient mapped image has more contrast and would be a much nicer image to start with if you were looking to produce a B&W image.
So what is the gradient map doing ? If you look at the small dialogue box below
You will see that the shadows are at the left and the highlights at the right and it has mapped the image with black in the shadows, moving through to white in the highlights. You can choose whatever colours you want. In the image below, of a rather sucky sunrise, I have chosen red as my foreground colour and yellow as the background. Applied the gradient map, changed the blend mode to overlay and taken the opacity down to about 40%. I could probably have used a mask to take away the molten lava look on the rock shelf 🙂
You can also check the Reverse box to change the way the image is mapped, in this case white is being mapped into the darker parts of the image, and black into the lighter parts.
With the gradient dialogue box open, click on the bar to bring up the gradient editor.
You will then get the gradient editor dialogue box. You can mess around with the presets to try them, I chose Silver from the Metal/s.
You could leave it at Silver if you wanted, but why not go ahead and see what you can create. The image below will give you a visual idea of the process.
Click on one of the colour stops – circled on the above image, and that will bring the colour into the colour box – outlined with a rectangle – you can go ahead and choose a new colour. You can see in the image above that all except one stop have been changed to blue – the other is a pink colour. I left the editor like that and clicked OK to accept it. You go ahead and fiddle around to your hearts content. I then changed the blend mode to Colour Burn and took the opacity down to 50%.
You can also add additional stops to the gradient if you want. Place your cursor just below the bottom line of the gradient bar (where the stops are) and you should get a little hand that says add colour stop (or add stop …. can’t remember) Also, if you come up with a gradient map that you would like to keep, name your map in the small box that says name … and then click save. See image below.
That is all there is to using a Gradient Map adjustment layer. You can do the wild and whacky thing, a B&W conversion, or simply use it enhance the colours in an image like I did with the sunrise image earlier on.