Fast curve color matching method for digital image

I hope this article can help digital photography enthusiasts and friends who love Photoshop to the digital image of "fast" "simple" color adjustment.

After opening the image in Photoshop, we can use the shortcut key CTRL M to pull up the curve adjustment function.

Before we use the curve adjustment function, let's briefly introduce the principle of the curve tool. Photoshop roughly divides the image into three parts: darkened, midtones, and high light. Like the following image:

We can use the "Go Color" command to convert color images to grayscale images, so that you can see the distribution of light and shade: The sky is partly high, and trees and grasslands are darkened.

The two endpoints of the line in the Curve panel represent the high light region and darkened region of the image, the remainder of the line is collectively called the midtones, and the two endpoints can be adjusted separately.

The following two animations demonstrate the effect of changing darkened and highlight points individually, with the result that the darkened or highlight portion is highlighted or dimmed.

and change the midtones can make the image as a whole highlight or darken (click in the line to produce a drag point), but the contrast has not changed (different from the brightness of the television increase), while the saturation of the color also increased, can be used to simulate the natural light intensity of the effect.

Now we properly reduce the dark harmonic and improve the high light.

Can get a strong image of light and shade (the so-called High Contrast)

But doing so may leave the image details of the lighter areas (such as clouds in the sky), and this does not conform to natural phenomena, by altering the midtones to create realistic landscapes.

So the image will look more natural, there will be no obvious changes in the traces.

In front of us, we are all tuned in to the overall image, now let's take a look at the effect of the channel adjustment alone, the electronic equipment produced by the red, green, blue color of the three colors in accordance with the different proportions of the mix, (near the screen of TV, you will see countless red, green and blue dots, Computer monitors are the same, but more subtle, in other words, the image displayed on the screen is actually made up of three separate colors red, green and blue, the so-called channel that refers to the individual red, green, blue part, also known as RGB.

If we highlight the red channel individually, it is equivalent to adding a red component to the entire image, and the whole image will be redder.

If we separate dark red channel, the result image will be green, green and red is inverted color (also known as complementary color), red and green, yellow and blue is also inverted color.

The inverse color is the relationship between the two:

To add bright yellow, then reduce the dark blue;

To add bright pink, then reduce the dark green;

To brighten the golden (golden yellow consists of red and yellow), you need to highlight both red and dark blue.

Now let's try to change the color of the sky part to Golden. Because the sky belongs to the high light area, we need to highlight the red channel's high light portion.

At the same time reduce the dark blue channel of the High Light section.

So we get a golden sky effect.

Although the effect is gorgeous, but carefully look at the distant green hills also turned yellow, the mountain should belong to the middle of the tune, so we in the red and blue channel in the middle of the original place.

So we get the golden sky, but also keep the blue of the distant mountain

As can be seen from the above example, the use of curve tools can be a very comprehensive color adjustment, in terms of digital post-processing (not art), it should be able to cope with most of the situation.