Black and white conversions

July 12, 2008

When converting color images to black & white, a common technique is to control how each color contributes to the resulting image.  This is the same idea as using color filters when shooting a black and white film stock.

In the two images below, the top image uses channel blending to use 70% red and 30% green while the bottom image uses the standard Black & White filter in Sony Vegas.  (These shots are from a music video.)  Controlling the black and white conversion this way can be used to increase contrast in the image.

Another way of changing contrast is simply to use curves with a s-shaped curve.  The image below shows curves applied to the image above (it may help to open both images in Tabs and to click between the tabs to see the difference).

An interesting way of doing black and white conversions is to use channel blending to decrease contrast and then use curves to add contrast back.  Doing this on the right channels can result in an image with increased detail and texture.  Michael Kieran talks about this in his book Photoshop Color Correction.  Results can be seen below:

Play around these techniques and see if they give you more dynamic shots!

Filed under: color correction |