Removing Colour Casts with HSL

Although the Lightroom HSL tool doesn't have the same level of control as Photoshop for selectively adjusting colours in specific regions of an image, the HSL tool is perfect for altering the hue, saturation and luminance of colour to the entire image.

With a little experience and know-how it's incredibly easy to remove colour casts without having to leave Lightroom.

One of my favourite uses of the HSL tool is to remove the colour cast from window light when balancing the colour temperature to the internal lighting.

The image below is an example of the typical colour cast that can occur when mixing light with different colour temperatures.

To clearly illustrate the colour cast I have increased the blue saturation to 100%. This is a simple technique I often use as a quick visual check for blue colour casts.

In this image I have balanced the white to the internal lighting and with the blue saturation set to 100% you can clearly see the colour cast created by the window light in the kitchen. To remove this I simply reduce the blue saturation until the colour cast is completed eliminated or until it's at an acceptable level. In the example below I have reduced the value to -100%

The unfortunate issue with this technique is that all the blue is removed from the entire image including any part that did not have a colour cast. An example of this this could be the groom's blue tie or someone's blue hat.

Fortunately there is a neat little trick that will resolve this issue. Simply take the Adjustment Brush and set the saturation to 100%. Now carefully paint over the areas that were inadvertently desaturated and the blue will return. Take care to control the density and feather of the brush so as not to further increase the saturation of surrounding areas.

This technique doesn't work with all images, but for a quick fix it's a handy tool to have in your toolbox and can even be used to remove green colour casts such as those you find from grass.

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