PulkownikSwiatlo
December 6th, 2006, 01:41 PM
So this is it: plugin free, do-it-yourself channel mixer.
1. Duplicate your background layer three times. The bottom layer name 'Background' and make it invisible. Name other layers going from bottom to top: 'Blue', 'Green', 'Red'. So Red is topmost, then there is Green in the middle and Blue beneath.
The order can be, however, anything you want, but the calculations are based on the spiecified order. If you change the order then make sure to adjust the calcs as well. The result will be the same.
2. Starting with the Red layer do this: apply a solid color fill adjustment layer to it, set the mode to 'Multiply' and fill with color RGB(255,0,0) (i.e. #FF0000). Don't forget to group it with it's base layer.
The result will be the image in the red channel.
3. Make another grouped Hue/Saturation layer where you set the saturation to -100. This will make a gray representation of the channel layer.
4. To the steps 2 and 3 on the Green and Blue layers, where the fill colors are RGB(0,255,0) and RGB(0,0,255) correspondingly.
5. Now we have three main layers named from top to bottom: Red, Green and Blue.
6. Change the contribution of each channel to the final image by moving the opacity sliders of the Red and Green channels. Make sure that the opacity of Blue (or the bottom channel) always stays at 100%. The opacity will have to be set according to the formula:
Opacity(Red) = Requested%(Red)
Opacity(Green) = Requested%(Green) / (100 - Reqested%(Red))
where Reguested%(color) is the desired percentage contribution of the channel.
For example, I wanted to set my B&W portrait to the desired channel contribution R=20%, G=70% and B=10%. To accomplish that, according to the formula the opacities should be:
Opacity(Red) = 20%
Opacity(Green) = 70 / (100-20) = 87%
7. At the end create a topmost Levels adjustment layer to adjust the overall image brightness and contrast.
For greater flexibility you can also play with the brightness and contrasts of particular channel layers.
I tested the formula on several images and it worked great!
The formula can be also used for chromatic channel mixing. To do that just omit step 3, i.e. don't desaturate the channel layers.
1. Duplicate your background layer three times. The bottom layer name 'Background' and make it invisible. Name other layers going from bottom to top: 'Blue', 'Green', 'Red'. So Red is topmost, then there is Green in the middle and Blue beneath.
The order can be, however, anything you want, but the calculations are based on the spiecified order. If you change the order then make sure to adjust the calcs as well. The result will be the same.
2. Starting with the Red layer do this: apply a solid color fill adjustment layer to it, set the mode to 'Multiply' and fill with color RGB(255,0,0) (i.e. #FF0000). Don't forget to group it with it's base layer.
The result will be the image in the red channel.
3. Make another grouped Hue/Saturation layer where you set the saturation to -100. This will make a gray representation of the channel layer.
4. To the steps 2 and 3 on the Green and Blue layers, where the fill colors are RGB(0,255,0) and RGB(0,0,255) correspondingly.
5. Now we have three main layers named from top to bottom: Red, Green and Blue.
6. Change the contribution of each channel to the final image by moving the opacity sliders of the Red and Green channels. Make sure that the opacity of Blue (or the bottom channel) always stays at 100%. The opacity will have to be set according to the formula:
Opacity(Red) = Requested%(Red)
Opacity(Green) = Requested%(Green) / (100 - Reqested%(Red))
where Reguested%(color) is the desired percentage contribution of the channel.
For example, I wanted to set my B&W portrait to the desired channel contribution R=20%, G=70% and B=10%. To accomplish that, according to the formula the opacities should be:
Opacity(Red) = 20%
Opacity(Green) = 70 / (100-20) = 87%
7. At the end create a topmost Levels adjustment layer to adjust the overall image brightness and contrast.
For greater flexibility you can also play with the brightness and contrasts of particular channel layers.
I tested the formula on several images and it worked great!
The formula can be also used for chromatic channel mixing. To do that just omit step 3, i.e. don't desaturate the channel layers.