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Photographic Tips & Techniques

Converting dull blue water images into black & white

If you've taken underwater pictures this is a fact: too many are an ugly shade of blue with poor color and contrast.  Here's an easy way to salvage the better ones and have fun with Photoshop.


Original color


From Grayscale command -

Prints will have magenta color cast


Desaturate command -

Prints will have magenta color cast

Channel Mixer - 

Prints will match screen


Creating a better B&W image

There are several methods to convert digital images to black & white, or more appropriately, shades of gray.  Although your results may not vary that much at first glance there is a big difference when prints are made at a local photo lab.

Easy but less desirable methods to convert color images to grayscale include 'Grayscale' and 'Desaturate' commands.  They don't provide control over highlight, midtones, and shadows and discard valuable color information.  This becomes a problem when printing at a color photo lab.  Since these labs use a color print process there will be an ugly color cast, usually magenta, if the operator isn't experienced enough to correct for it.  Even with professional help there will be some trace of color in the finished print.  I would add blue and cyan to grayscale images to compensate but the resulting print had faint blue highlights.

The Channel Mixer in Photoshop is my preferred method for creating good grayscale images that look and print great.  The secret behind this is retaining color information rather than discarding it during conversion.  In other words, you are working with a full-color image that simply looks black & white.  Color lab prints made from these files look exactly like they do on screen.  In addition you are able to make an unlimited number of adjustments for highlights, midtones, and shadows by moving individual color sliders.  Be sure to save your creation as a new file so the original can be used again.