Color Channels

[imgaryshap74]

Hi All, 

I have an image of a map that I want to change the colors on.

I thought the simpliest way was to duplicate the image, and then remove a color from each layer in the color channels window.  In the end i'll make each layer accordingly so as to create a red > white > blue color gradient acoss the entire image. (I'm sure there are numerous way to do this, but this was how I started).

However - once I make a change or remove a color (for example - unclick "Red" and the entire image turns blue), this applies to all layers AND it does not stay.  The moment I click on another layer, the color channel defaults back to the original image and all colors are selected.

What am I doing wrong?

I'm running Photoshop 25.9.1 on an Intel Macbook Pro using Sonoma 14.5

[Chuck Uebele]

When you turn off a color channel, the color you see will be that of the remaining channels, and if you really wanted to keep the look of with the channel removed, you need to create a new layer, and paste each of the channels that you like into the channels for that layer The ones that you don't want, should be all black. There are lots of ways to do this.

If you just want to change the color, I would try a hue saturation adjustment layer, and change the hue.

[Conrad C · Accepted solution]

Channels isn’t the best way to do this, because a channel is a component of the pixels themselves…so any change to a channel necessarily alters the color of all pixels (the entire original image), and can’t be controlled at the layer level.

You are correct that there are many ways to do this. One way is a gradient blended with the map. Create a Gradient Fill adjustment layer with red, white, and blue color stops, and use a layer blending mode (I used Color) to apply that so that it replaces the map colors. The colors are hard to see because the original map is so dark, so to lighten the dark areas, I added a Curves adjustment layer applied using the Screen layer blending mode.

If you think the white is still too hard to see, you can add another layer that lightens just the middle part of the map so that the final color looks more white. The problem is that the original map is so dark, and the light areas so small, that when you apply white to the middle stop of the gradient through the Color blending mode, the middle part of the map is too dark to look white.

[imgaryshap74]

This is exactly what i wound up doing.  Was just wondering about the channels and your explanation was helpful.  Thanks!