Updated : 2021
window menu
channel command
go to the channel panel in Photoshop
select a brush
go to the red channel
apply brush stroke to red channel etc
How to use Color Channels and Photoshop brushes tutorial, using Red and Green and Blue channels split and merge. Photoshop brushes can be used with color channels on the PC and MAC.
You can use the color channels to create all kinds of super interesting color effects with the Photoshop brushes. You can use the Photoshop brushes on different color channels via the channels panel.
Select the red channel or cyan channel etc and then add the Photoshop brush strokes to that. You can then select another color channel and apply another or the same Photoshop brush to that and so on. You can also combine effects with the Photoshop brushes and the color channels. You can also then use adjustments to further modify the result of the color channels. This tutorial shows you how to use the color channel panel and use the channels with the Photoshop brushes.
It also shows you how to use them in separate channels and use with effects. The tutorial finishes off with showing how to create even more amazing color effects with channels and the brushes with adjustments in Photoshop.
Select channel red
Select channel green
Select channel blue
To return to before, select RGB
The key thing is that you have the channel panel displayed (found via the window menu). The channel panel for RGB is made up of a red channel, green and blue with a little eye / visibility indicator which can be turned on or off.
Select the brush tool
Select red channel
Apply brush in black or other color
Select blue channel
Apply brush in black or other color
The strokes can be applied to the red channel and then applied (the same or differently) to the green channel and to the blue channel. You can then re-combine the end result strokes into RGB. Of course, if you are in LAB mode then you can do the same with lightness and the A and B channels. The strokes work in most of the color modes as well as 8 bit and 16bit modes and beyond. The Photoshop brushes and channels (and image modes) are a really flexible feature of the application.
And you don't just have to use the brush tool, you can use the smudge tool instead. You don't have to add them to all the channels either so you can fill the red and green and totally leave the blue alone. The end results also depends on the color of the strokes.
Select brush tool
Apply brush stroke to red channel
Go to the filter menu and blur and gaussian blur
OK
Go to the green channel and so on
You can use strokes across channels, you can also combine them with effects. Add stroke to the red and then to the green etc and then use an effect in the red or green etc and in most cases you will find that you can combine the artwork with effects - most filter gallery effects are fine but you may find that some cannot be used with a single color channel such as the blur gallery. How to resolve this ??
Go to the channels panel
Right side menu
Split
If there are effects that cannot be used in a single channel, use the split.
You can use the split command which will split the RGB etc into red, green etc images (all in grayscale). You can then use the channels as well as the Photoshop brushes / channels with most of the effects such as the blur gallery as well as add more strokes to the artwork. If you wish to use filters that cannot work with grayscale then just go to the image mode and set the image mode to RGB. How to get back to a standard RGB document ?? Just use the merge command found in the panel (window menu).
You can then bring back the all the images as red / green / blue - you can also even get creative there as you can bring back the red channel as the green channel, the blue as the red and so on resulting in some truly abstract artwork.
Select brush
Go to channels
Select the red channel
Go to the little selection button at the bottom of panel and click
Apply brushes
Select menu and deselect
Go to the green channel and repeat
You can use them across red, green etc but you can also apply strokes to the red channel combined with a selection; you can also do the same with the green but with a different selection etc. You can use multiple selections and multiple strokes in different locations to create all kinds of extreme color effects.
Go to the red channel
Apply brush stroke to channel
Go to the green channel
Apply different brush stroke etc
Go to the image menu
Adjustments
Invert etc
Go to blue channel etc
You can add into the mix adjustments. Go to the individual red and add a stroke and then the green and add a stroke etc and then go back to the red one and you can then go to the adjustments in the image menu. You will notice that not all are available and you will be able to use invert, threshold, posterize etc It is odd that some of them such as exposure are not available but I guess that is the way they are coded and you will find that if you go to the 32bit channels etc even less adjustments are available.
If you wish to use adjustment layers (as well as the other adjustments) then the only way to do this would be to use the panel and then split the image into grayscale and then set to image mode RGB and then use the adjustment layers with the full range of colors and then merge them all back together