Black-and-white imaging is tricky - if it's done well, it looks amazing; but if it's done poorly it looks awful.
So what's the key to a good one? Well, it's right there in the name -
black and
white.
The name of the craft is not "Shades-of-dark-grey-and-light-grey photography". It's "Black-and-white photography".
For a B-W photo to smack the viewer in the face, it needs to have plenty of blacks and whites. Any area of significant detail without a black and a white in it somewhere is flat, dull, and uninspiring. The photo needs plenty of contrast, not only globally, but in all the detail.
Let's take a look ...
Here's a snap, desaturated. Flat, right?
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Here it is with contrast improved globally. Now it has at least one area of black and one area of white in it. Better.
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Now it's had the works - plenty of selective enhancement to create plenty of contrast. Much better!
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Now I've pushed the boundaries, searching for that really stark effect. This may not be to everyone's taste ...
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... but you can't deny it's much more eye-catching than where it began:
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*shudder*
See what I'm talking about? Plenty of areas of black, and plenty of areas of white. That's the key.
Let's look at another. Here's the photo, desaturated. Not very inspiring.
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Now, with global adjustment. Slightly better, but not much.
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Now with selective adjustments to find plenty of local contrast. Looking good!
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Finally, with a moderately aggressive S-curve for the strongest effect.
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So, when you are evaluating your next black-and-white photo, take a frank look and ask yourself "what's boring about this photo?" It might be a bland background, or some dull clothing, or the whole darn image! I guarantee that if you improve contrast to create blacks and whites, it will look much more exciting.