Lightroom Tip: Adjusting Colours using the Tone Curve
Today's tip is all about the RGB Channels in the Tone Curve in Lightroom. Most of us use the Tone Curve to adjust luminosity and contrast in our images. But did you know that you can also use it to colour grade your images, using the RGB channels in the Curve?
The first thing you need to do is set your Tone Curve into a draggable tone curve (instead of the tone curve with the sliders for highlights, lights, darks and shadows). If your tone curve still has sliders on it, click the little tone curve icon (yellow arrow in the image) to switch to the draggable tone curve.
Then, you can simply drag points on the curve to adjust contrast and so on. But, if you click on the Channel drop down box (red arrow in the image), you can select one of the three channels (R, G or B) and then drag and drop that channel to adjust hue and colour for each of the three channels (Red lets you adjust between reds and cyans; Green adjusts between greens and magentas; Blue adjusts between blues and yellow). As the tone curve allows you to adjust for different tonal areas within the image, you can do the same with the R, G or B channels for the different tonal areas in this image. For instance, in this instance, raising the reds in the highlights infuses the sky with red, while dropping the reds in shadows gives the darker mid-tone areas in the image a blue/cyan cast.