Do you want to beautifully increase the contrast of a color photo or quickly create a mask, saving as much time as possible and avoiding manual painting with a brush? Do you need to cut out a solid background or a person, while maintaining a neat outline of the hair? Or maybe you are tired of presets and filters and want to tone the photo yourself?
In any of these different and sometimes difficult situations, the same thing will help — working with channels. Yes, those very incomprehensible ones that cause horror among beginners. We tell and show visually what trichromatic channels are, and also share tricks on how to cut out the background using channels, tint, increase contrast and quickly get black and white photos.
What are channels in Photoshop
Our vision consists of 4 sensitive cones, three of which are responsible for the perception of the three primary colors — green, red and blue. When looking at an object, such as an orange, the red cones will react more strongly, while the green and blue cones will react less. It is their joint work that helps us to see and perceive the whole variety of colors.
Channels in Photoshop are essentially three layers—red, green, and blue—that add up to the color image as we see it. It turns out that in each color there is a certain amount of each of the three colors.
If you take green, blue and red dice and go to the palette Channelsthen the following is seen:
- Red channel. With the help of white and black, it shows where there is a lot of red, and where there is not enough. If you click on it, the red plate will be white, and the green and blue ones will be black.
- Blue channel. Works the same as red. Where there is a lot of blue, the black-and-white image will be white or light, and where there is little, black or dark gray.
- Green channel. The same as with blue and red. Light areas are where green is present, dark areas where there is little or no green.
All three colors add up to white. That is, if you see a white sky in the photo, it means that there is blue, red, and green in the maximum possible amount. By contradiction, black is the absence of all three colors.
Where are channels in Photoshop?
To find channels in Photoshop, in the command line at the top, find the menu Window / Window — Channels / Channels. After that, a special palette for working with channels will open.
Why channels are needed — 4 processing steps
Channels can be affected separately by changing color and contrast. But, what is even more useful, the desired channel can be “isolated” in order to make a mask based on it, cut out an object or get a black and white photo in a couple of seconds. We tell you how to do it.
Color grading with channels
By influencing the amount of a certain color in the channels, you can create many high-quality tonings in a couple of mouse movements.
Important: colors change best and most noticeable in bright photographs with a wide variety of shades. For example, if you are photographing with colored light or just bright objects. It will not work well to make a color correction of a winter landscape with a minimum of colors — it will come out dirty and ugly.
1. Open the palette Layers (you can quickly do this with the 7 key) and click on the black and white circle.
2. In the list of adjustment layers that appears, select Channel Mixer.
3. Click on the drop down list Output Channel. You will see three colors — red, green, blue. Select the color you want to change. For example, if you want to affect red, then choose red. Use the Red, Green, and Blue sliders to change the amount of color in the channel.
Thus, by switching between channels and moving the sliders, you will get a unique tint.
Important: below is the total number of colors in the channel. It is represented by the inscription Total / Total: +70% (for example, as in the screenshot above). For the correction to be of high quality, do not allow the sum of the channels to exceed 150–190% (depending on the specific photo).
Take a black and white photo in 30 seconds
Open palette Channels and switch between them. Choose the channel with the black and white image that you like the most. Remember your choice.
2. On the palette Layers click on the black and white circle and select Channel Mixer.
3. Click the checkmark Monochrome / Monochrome. The picture will turn black and white.
4. To get exactly the image that you liked in step 1, in the sliders with channels, put 100% in the channel that you liked, and 0 in the remaining two. Ready!
How to remove background using channels
With the help of channels, you can cut out the background, even if the object is quite complex. For example, a tree with a lush crown or a person with fluffy hair. Also, the channels easily cut out a solid background. For example, if you took pictures with chroma key.
1. Create a duplicate of the original layer using the hot keys Ctrl + J.
2. Open the palette Channels and click successively all three channels. You want the one where the background and subject are the most different from each other.
3. Holding down the left mouse button, select the channel with the highest object/background contrast and move it to the plus sign in the Channels menu.
4. Go to Image / Image — Corrections / Adjustments — Levels / Levels.
5. Click on the dotted circle in the Channels panel.
After that, switch to the palette layers, select the copy of the layer and click on the black rectangle with the white circle — the mask created based on the channel will be applied to your copy of the layer.
Important: If the object is missing instead of the background, click on the mask and invert it. To do this, press Ctrl + I.
6. If the mask turned out to be imperfect, it needs to be finalized! Open palette Propertiesclick on the picture icon in the palette Layers / Layers and click Select Object / Select Subject.
A dotted line will crawl across the object — marching ants. Take a Brush / Brush and white paint over the object inside so that it becomes pure white.
7. To refine the background, paint over the areas that are not being painted over with a regular black brush.
Thus, you can not only cut out the background, but also create any mask that you will later use in processing. For example, to recolor parts of a photo.
Boost Contrast with Channels
If you raise the contrast through one, common slider, the brightness of all three channels changes the same way. And often it ruins the photo. For example, you want to increase the contrast in a portrait. Skin is a reddish color, meaning the red channel will be the lightest. But the brightness will rise equally in blue, and in red, and in green, that is, for example, the blue channel will become a little brighter, and the red will turn into a solid white spot. Because of this, the result will be clumsy and rough. We tell you how to get a more accurate and eye-pleasing result with the help of channel-by-channel contrast enhancement.
1. In the palette Layers click on the black and white circle and click on the adjustment layer Curves. Read more about what curves are and how they work.
2. Click on the RGB drop-down list (in curves this is called the master channel, the sum of all three channels). You will see a list of three curves — red, green and blue. Left click on any of them. For example, you can start with red.
3. Place the foot on the lightest area of the person’s face. Hold down the left mouse button — a point will be placed on the curve. Without releasing the button, lift this point slightly up.
Place the foot on the darkest area on the human skin. Put a point on the curve by clicking the left mouse button, and, without releasing, lower the point a little down.
4. Repeating point 3, in the same way raise the contrast in the remaining two channels — green and blue. If the correction seemed too strong for you, go through the channels, adjusting the height of the set points, or lower Layer Opacity.
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