Ever wondered what RGB means in photography, or indeed why astrophotographers talk about RGB filters?
Colour images are made up of data collected using red, green and blue (RGB) filtering.
On a ‘one-shot colour’ camera like a DSLR or colour astro camera, tiny filters are built into the sensor surface, but if you’re using a mono CCD or CMOS camera, the filters have to be introduced externally.
Usually, red, green and blue filters are held in a filter wheel that will allow you to capture a series of images.
These images are then stacked in their colour groups and combined in image processing software to produce a single RGB colour image.
It is possible to create an image using just red and blue - read our guide on how to create a synthetic green channel for more info.
