Creating Black And White Images Using Photoshop Channel Mixer

1. Select the channel mixer from the adjustment layer popup menu in the layers palette. You can also access the channel mixer by selecting it from under the image menu. Opening the channel mixer from the adjustment palette allows you to modify your grey scale conversion if the need arise.
   
   
2. Check the monochrome check box at the bottom of the channel mixer window. Checking this box gives you the ability to blend the red, green and blue channels of your grayscale image.
   
3. Using the sliders on the channel mixer move the red channel slider to a value of +60 and move the green channel slider to a value of +40. The values I have given you are simply starting points, you can tweak the image to your liking. As a rule make sure that the total values selected for each channel adds up to 100%.
4. The brightness of your image can be adjusted with the use of the constant slider at this point.
5. Click Ok and the channel mixer is applied to your image.