There was a recent question on the iColorama Facebook page about the purpose of the Range command. I decided to put together a quick blog entry to help explain. There is a silent video embedded here, and the explanation of that video is right here.
Range is used to build a mask. In other masking tutorials, I have explained how to use the Threshold command to build a black and white mask which can then be re-imported. When you create an iColorama mask, black reveals the changes you are making, while white conceals those changes. Black reveals, white conceals. When you use the Threshold command to create a mask, as I show in the beginning of the video, the resulting blacks and whites are based on the luminosity, or brightness, of the underlying image. So as I adjust the Threshold, you can see that both the dark green leaves and the dark trunk are turned to black, while light green, blues and grays are turned to white.
But what if you want to mask certain colors instead? When you want to change the greens in the image, but not the reds of the same brightness, you turn to the Range command. I use the Blacks color picker, and the eyedropper tool, to pick up a green color, and everything turns black. Then I pick a light blue from the sky with the Whites picker, and the mask begins to take shape. I choose another color with the Whites picker, and another green with the Blacks. I Apply those changes. Then, since I know that I will not want the changes to apply to anything in the lower part of the image (green or not), I paint white over the bottom. Then I save the mask, return to the original photo in Steps, and re-import the mask in the Brush Mask area.
My first change uses the Hue command to change the color of the leaves to pink. The resulting image is below.
Of course, just because I use color to determine the mask doesn’t mean I have to change the color. In the second example I use Tensor and Painterly>Van Gogh 1 instead.
I hope that that gives you an idea of what Range can do for you! Enjoy!