Channel Mixer is a great tool for not just adding color saturation to an image, but also in creating well-toned black-and-white (BW) images. Go to Image > Adjustments and select the Channel Mixer controls. When the dialog box opens click the Monochrome check box. You will see the Output Channels setting change to Gray. The Red, Green, Blue sliders now become gray channels. There is a set of numbers that I use to begin my conversion to BW.
Red at 70, Green at 16, and Blue at 14. Then I select OK and apply the changes. Now I go to Image > Adjustments and then go to the Brightness and Contrast setting and apply 12 to the contrast setting. This is my basic setting to create the initial BW image. I have tried applying the initial amount of Contrast in the Contrast Control in the Channel Mixer but find it comes on a lot stronger by using that adjustment. I created a simple action for this set of BW tool applications.
You can also create the same BW image by going to the Adjustment Palette, selecting Black/White (the half black and half white square) and entering the same numbers, leaving the yellow, cyan, and magenta colors at zero. A white mask is added to that layer (black conceals, white reveals) so you can paint out parts of the BW mask. Neat. You can also try some the Custom settings which will tone the BW differently. You can also use the AUTO button to see how the programs interpretation of the scene might vary, then make your corrections accordingly.
As you can see in the bridal example above, just desaturating the colors (in the Image > Adjustments > Hue/Saturation dialog box) leaves a murky, poorly toned BW. The Saturation slider provides linear adjustments to all colors (including Yellow, Cyan, and Magenta) that bias the BW grayscale image. I’ve never created a BW that I thought looked good just by desaturating. But there are other ways to create a great BW image in Photoshop.
In the image below, right, of the lone oak tree in a meadow of green in Yokohl Valley, Ca – I found that by going to Channels Palette (usually located with the Actions Palette) and selecting the Green Channel I got a better BW image than I did by either desaturating or using the Channel Mixer.
These different ways for creating a black-and-white image are only the starting point.
Once you have a well toned BW layer, then other tools can be brought into play to tweak that image. Local contrast can be added using a mask and sharpening can be applied. Many BW images will benefit from the “grainier” appearance of over-sharpening, similar to the look of Kodak’s 400 Tri-X film, an industry standard look back in the day.
Another way to tweak your BW is to adjust the levels of each color (as shades of gray) in either the Channel Mixer or in an Adjustment Layer BW. Your eye might like a different mix of grays, or even more contrast in that initial conversion to gray.
There are many software programs out there that (for a high price) will perform the same functions, using basically the same tools – the Channel Mixer and/or Adjustment Layers. Learning these valuable tools allows you to move your photography to a higher level – especially since BW imaging has had traditional marketplace appeal.
Create Actions for each of these different tool applications and if the first step of the Action is to create a New Layer, you can run them one after another to see which provides you with the best starting point for you BW image.