Curves

Another way to carry out color corrections, is by means of the option “Curves”.

In the previous lesson we saw how we are using “Levels”, a color correction that can take on three points, highlights, midtones, and shadows.

When we use curves, we can customize each of the 256 gray levels.
In this example I’ll show you how to adjust the brightness and contrast through curves.
As always, I start to make a copy of the original photo.

Open the window “Adjustments”, and click the “Curves”.

This opens the panel “Curves”.

First, let us first see what we have here.
What is most striking is the diagonal line (1) in the graph that runs from the lower left to upper right corner.

The point in the upper right corner represents the lightest color, the point in the lower left corner represents the darkest color. In between, there are various shades of gray.

At the bottom of the chart we have two bars, which are provided with a gradient from black to white (2).

The graph under that represents the display of the picture at that time.

When we work with curves, old display is replaced with the new display.
This new display is seen in the vertical bar.

As an example, I want the midtones of the image lighter. How do I proceed?

The mid-range are located in the middle of the graph. So I click in the middle of the chart and drag the mouse pointer up.

You can see that the horizontal axis is moving upwards (2), and the new midrange is lighter.

The later can be seen at the intersection of the horizontal axis with the vertical bar (3).

A number of different preset curves are present in the “Curves” (4).

By now you know that you should try this and see how the diagonal line is adjusted to the option you have chosen.

The first thing we do is to check the “Show Clipping for Black / white points” option so that it is activated.
Just click the downward pointing arrow in the title bar of the “Adjustments” panel, and click this option.

Then we set the light colors.
Click and drag the white triangle at the bottom the graph from right to the left (1). Once you see the white color appear in the picture, release the mouse button.

We do the same for the dark colors.
Click and drag the black triangle below the graph from left to right (2). Once you see the black color appear in the picture, release the mouse button.

And finally we fit the curves on the “Curves” panel.
For this, select the “Edit Curve” button in the “Adjustments” panel and click and drag the picture up or down. Move the mouse pointer up, the picture becomes lighter, move it down, the picture becomes darker.
As you click and drag the cursor, you will see the curve move and you will also see an example in the picture.
This places a point in the curve at the position of the cursor (4).
If you want this particular place in your picture darker, you can still drag this point to the right. If you want it lighter, slide your point to the right.

If you want multiple reference points on the diagonal line in the graph, you can do this with the “Curve editing” button or by clicking on the diagonal line. When you choose the later, you do not know, of course, what position it represents in the picture.

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