What is saturation?
Artists and photographers use hue, saturation and lightness (HSL) to describe colour. Hue refers to the dominant wavelength of light that the human eye interprets as colour, but you can think of it as the basic colour on the colour wheel. Saturation describes the intensity of the colour. And lightness refers to how light or dark the colour is.
A grayscale or black-and-white photo has no colour saturation, while a full-colour photo of a field of sunlit wildflowers might be extremely saturated. Some photos are naturally more saturated than others, but how much you decide to add depends on your subject and your intention.
How saturation changes the feel of a photo.
Highly saturated photos can look artificial, so use saturation with care — especially if you’re going for a natural look. Many people can tell when photo saturation has been altered. We judge the health of plants and the freshness of food by colour, so we notice unnatural saturation shifts very quickly.
If you want to create surreal images, you might make larger shifts in saturation. But for realistic pictures, keep real-world references in mind as you edit, so you don’t overdo the colours. “It’s rare to see pure colours in nature because ambient light makes colours less saturated,” says photographer Heather Barnes. “That’s why you have to be really careful in post to not overly saturate your colour.”
Make slight moves for big impact.
Consider what you’re trying to say in your photography. If you want to capture a foggy mountain lake early in the morning, you might find that low saturation adds wistfulness to the photo. With fashion photos, you might want the colours in an article of clothing to stand out. “Think about the story you’re telling,” says Barnes. “Maybe you take a picture of a woman in a red dress and you want it to have this vibrant, fiery feel. In that case, boost the saturation.”