The answer to how do you convert a digital photo to black and white in Pixelmator may seem obvious to anyone with a little experience of the image editor. However, while the Desaturate command is a one click process, it lacks any degree of user control.
Photoshop users will be familiar with the Black and White adjustment tool that allows you to fine tune how the final mono image will look by adjusting six different colors individually. In practice this opens up the possibility of producing very different looking black and white images, all produced from the same original color photo.
Before the introduction of the Black and White adjustment tool, the Channel Mixer in Monochrome mode was a popular, though slightly less versatile, way to achieve different results and for many GIMP users, this remains the favored option.
At first glance of the different adjustment tools available in Pixelmator, it would seem that the Channel Mixer will also be the favored technique for converting digital photos to black and white. However, on closer inspection, you'll see that the Channel Mixer control doesn't have the Monochrome option available in Photoshop and GIMP and so is a non-starter.
However, there is always more than one way to skin a cat and in this basic tutorial, I'll demonstrate how you can use the Hue and Saturation tool to make some preparations to a digital photo before applying the Desaturate tool to convert it to mono. This isn't a perfect technique and it is prone to introducing a bit more noise to your images, but that may give the converted images a feeling of grain from traditional black and white film photos.