There are a number of ways to convert colour images to black and white in Photoshop. You can simply convert to grayscale via the colour mode menu (Image > Mode > Grayscale), or simply desaturate the image. In this tutorial we are going to crate a black and white image using the channel mixer.
For this tutorial I’m using an image I took from the South Bank in London. Below you can see the outcome of just regularly converting to grayscale, the results are flat and dull, we want an image that has a little more ‘punch’ and contrast.
Below is a black and white conversion using the channel mixer. As you can see, the result has far more impact and contrast.
Making the conversion
To start using the channel mixer we create a new adjustment layer, this way our editing is non-destructive and can be changed or deleted at a later point if we wish. To achieve this we select a new adjustment layer from the menu at the bottom of your layers palette in Photoshop, then select channel mixer in the menu, that will then bring up the options for the Channel Mixer filter.
The panel below shows the settings I used for the final shot in this tutorial. Let’s look at the options in more detail. Firstly you need to check the ‘monochrome’ option. Then you can select from the preset filters menu if you wish. These simulate the image as if it was originally shot with a coloured filter over the lens, so there are green, red, blue orange options etc. These presets can produce reasonable results, but below I have created custom settings, this is the best way to get the exact results that you want.
To customise the settings simply drag the red, green and blue sliders shown above to get your desired effect. You will normally be looking for good contrast from a black and white image. You will notice the ‘100%’ total shown below the sliders. The general guide here is that the combination of all three colour channel settings should equal 100%. You can break this rule of course, but you may lose tonal detail by doing so, so it is something worth keeping an eye on.
The final ‘constant’ slider makes the overall image darker if a negative value if used, and conversely adds more white to the image with a positive value. For this image I added a small 5% value just to make the whites pop a little more. And that’s it, have another look at the final image below: