Colour Wheel

The Colour Wheel Reference Tool

A simple but genuinely useful device, this colour wheel reference tool is something you can reach for in a number of different situations – whether you’re hunting for complementary colours to use in a design or composition, or whether you’re trying to understand and fine-tune how different black and white conversion methods affect the tones in your image. The image has six different areas, each serving a distinct purpose:

1. The colour wheel itself is the most obvious element. It shows the entire range of hues arranged in 10 degree steps, each rendered at 100% saturation and 100% brightness. Think of it as a complete map of colour, giving you a clean reference point before any conversion or adjustment is applied.
2. Ring ‘A’ shows the brightness of each of those hues when overlaid with a Desaturate layer in Photoshop. What’s worth paying attention to here is that the brightness of every single segment comes out identical. That’s the nature of a straight desaturate – it treats all colours as equally bright, which is rarely how our eyes actually perceive them.
3. Ring ‘B’ shows the brightness of each hue when overlaid with a Channel Mixer layer in Photoshop set to Red=30%, Green=60%, Blue=10%. You’ll immediately see how differently the tones fall compared to Ring ‘A’ – reds darken, greens lift, and the whole conversion takes on a more considered character.
4. Ring ‘C’ shows the same Channel Mixer approach but with different values: Red=21%, Green=71%, Blue=8%. These particular numbers are a close approximation of how the human eye naturally weighs luminosity, placing heavy emphasis on green and very little on blue. It’s a subtly different result to Ring ‘B’, but on certain images the difference can be quite striking.
5. A 24-step tonal graduation from black to white. This gives you a clear, stepped tonal scale to compare against – useful for checking whether your black and white conversion is holding detail at both ends of the range.
6. A 256-step tonal graduation from black to white – essentially a continuous, smooth ramp covering the full tonal range available in an 8-bit image. Where the 24-step version shows you broad jumps, this one reveals the finer gradations in between.

Import the file into your editor of choice, or simply overlay the colour wheel onto your image as a temporary layer, and you’ll be able to see at a glance what difference each black and white conversion strategy has on the outcome. Comparing Ring ‘A’ against Ring ‘C’ side by side is often enough to make you think twice about ever reaching for a straight desaturate again.