my flickr photostream

Monday, June 8, 2009

Converting to Black and White

Yosemite B/W
© 2009 Simon Hucko

Today's post is about converting your color shots to black and white. You can just click the button to make the conversion, but to get the best black and white shots you're going to want to do some additional work.

Take the two images below:

© 2009 Simon Hucko

© 2009 Simon Hucko

The conversion to black and white really makes the texture of the trees stand out.

I did the conversion in Picasa, but the principles are the same no matter what editor you choose. The first step is deciding how you want the color channels (RGB) to be represented in black and white. You could just completely de-saturate the image, which will leave you with the luminance portion of each pixel. However, this will usually not give the best results. Using a channel mixer to decide how much of each channel gets used can help enhance the contrast of your image and generally produces a better result. Picasa doesn't have a channel mixer, but it does give you the option to do a "filtered black and white" conversion. The reference is to when photographers used to put different color filters over their lens before shooting on b/w film to enhance contrast or produce a specific look, but essentially it behaves like a channel mixer. See here for a good explanation on how this works.

After doing a filtered conversion, you're also going to want to tweak the levels in your photo. Colors appear more saturated at lower luminance levels, and while texture is important, color is usually the dominating source of contrast and interest in a picture. When converting to black and white, all you have is texture and tones to make an interesting image. Contrast and detail become very important. I boosted the highlights and the mid-tones of the above shot in order to bring up the texture on the bark. Generally, a boost in the highlights and mid-tones will be required. Things that look almost white in color can take on a gray cast when converted, and that will have to be corrected for.

I haven't really done much black and white up until now, but after playing with the Yosemite pictures and doing several conversions (see album here) I may have to do more.


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