I am not sure how many people out there in the industry use this. When I first learned this trick it really struck a chord with me. Have you ever had an image that just was destined for black and white, but when you converted it things were just "off?" Perhaps it had too many low key-tones or there was a section that was too dark and automatic conversion just wont cut the mustard or maybe you just want more creative control over your image. Let me share my secret with you. Actually how much of this is a secret I really can't say. It just sounds better when I use the word secret...
The name of the game is splitting channels. The program, Photoshop.
Step 1: Splitting the channels of a RGB file. You do this by selecting the channel tab in the Layers Panel. You then click the carrot in the panel. A drop down will appear. The option to separate channels will be available. Select this option.
Step 2: At this point you will see three separate canvases open up each on is a different gray-scale file.
Step 3: You then compare the three separate images against a the single desaturated RGB image.
The red channel is loaded with highlights - notice them predominantly in your Red Channel image? Green Channel has more middle tones and finally the Blue Channel holds the darkest values. A lot of times you may not even need the blue channel image. In some cases, you can chose to use it as a layer mask for extra depth as you build your final piece. The Blue Channel typically holds the most noise if you're shooting at a higher ISO. Eliminating or minimizing the use of the channel can clean up you B&W image quite a bit.
Step 4: Loading the channels. Simply copy and paste (or click and drag) the green and blue channels into the red channel file. Or the Red and Blue Channels into the Green file. It doesn't matter as long as you have all three channels layered in one file.
a.) I sometimes place the green channel over the red channel, and change the layer properties of the green channel to "soft light" to blend the two layers together. This deepens some of the shadows and softened some highlights. Play with the opacity until you like it... you can also mask off some areas as well. It's wide open to how you want to work it.
b.) I then place the Blue Channel mask on the top layer and air-brush at 20% just to bring back some details in the shadows adding some extra depth and a bit more tonality. As mentioned above, sometimes this layer isn't even necessary.
Lastly: My final 3-minute B&W Conversion. It's a different way to control your digital B&W conversions.
posted by http://michaelabela.weebly.com