| Firstly, one can use the Desaturate Command in Photoshop (PS)
to convert a colour photograph into black and white, but this gives no
control over the tonal range.
A far better option is to use the Channel Mixer tool as this allows you to have control over the tonal range of your photograph by mimicking the filters one would commonly use in black and white photography. |
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| Here we can see the result when just using the Desaturate
command. While it does a far job, the resulting image is dull and lifeless.. |
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| Now we bring the Channel Mixer into play.
Image>Adjustments>Channel Mixer. Make sure the Monochrome button is checked. |
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| As we can see, when using the default setting of the Red Channel
at 100%, this mimics the effect a red filter would have on BW film. The sky has darkened and the red tin roof of the church has lightened a touch. The tonal range so far is still a bit flat, but we will fix that later on. |
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| Setting the Green slider to 100% instead gives this result. Notice how the foliage has lightened as it is green. |  |
| Setting the Blue slider to 100% The sky has lightened considerably. |  |
| I have chosen to go with the red channel set at 100% as I would normally shoot with a deep red filter as prefer my skies to be dramatic and dark. | |
| The next step is to open the Levels Palate.
Image>Adjustment>Levels.
This shows a Histogram of the tonal range of your image. Working from shadow detail on the left to highlights on the right. Probably the easiest thing here is to take the eye dropper tools and mark your absolute black and absolute white points. I chose to set my BP in the window on the left and the WP in the cloud. This should give you a better range of tones. But we aren't done yet.. |
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| Open up the Curves Palate. Image>Adjustment>Curves What we are going to do here is to adjust the contrast to that we have a bit or punch to the shot without losing shadow detail or highlight detail. An 'S' curve is what we need here.. click on a point on the bottom of the curve line and roughly where shown and pull the curve down a touch. You should notice the shadow areas on your shot darkening a bit. Do the same at the top of the curve, but pull the curve slightly upwards. This will brighten the highlights without degrading the shadows. |
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| When you are done you should have an image that is full of tones
for you to work on. You now have a basic black and white image, all
you need to do now is to dodge and burn so you make full use of
your tonal range..
This will be covered in my next tutorial. |
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