How to Convert a Digital Photo to Black and White in GIMP

There is more than one way to convert a photo to black and white in GIMP and which you choose will be a matter of convenience and personal preference. It may seem surprising to hear that different techniques produce different results, however, that is the case. With this in mind, I'll show you how you can take advantage of the Channel Mixer feature to produce more striking black and white photos in GIMP.

Before considering the Channel Mixer, let's look at the easy way to convert a digital photo to black and white in GIMP. Typically when a GIMP user wants to convert a digital photo to black and white, they'll go to the Colors menu and select Desaturate. While the Desaturate dialog does offer three options for how the conversion will be made, namely Lightness, Luminosity and the average of the two, in practice the difference is often very slight.

Light is made up of different colors and the proportions of the different colors will often vary from area to area within a digital photo. When you use the Desaturate tool, the different colors that make up the light  are treated equally. 

The Channel Mixer, however, allows you to treat the red, green and blue light differently within an image meaning that the final black and white conversion may look very different depending on which color channel was emphasized.

For many users the results of the Desaturate tool are perfectly acceptable, but if you want to take more creative control over your digital photos, then do read on.

• How to Convert a Digital Photo to Black and White in GIMP
• The Channel Mixer Dialog
• Convert a Photo to Black and White with a Dark Sky
• Convert a Photo to Black and White with a Light Sky