What is the role of mask in ps? There are also channels.

Masking is used to cover the parts you don't want. For example, if you have a square picture, but you want to turn it into a circle, you need to use a mask here. You should first draw a circular selection on the picture with the selection tool, and then make a mask on the picture, so that the picture becomes circular. Masking is to cover up the part outside your drawing constituency and achieve the desired effect of your drawing constituency!

What is Channel One?

If you feel headache when you see this topic, then-this is a good opportunity to help you master the article thoroughly, or it may be your last headache.

No matter in all kinds of computer magazines or online media, there are endless articles about photoshop channel, but there are still so many people who are confused. So, what is the channel? It can be said that the channel is the constituency.

It sounds simple (in fact, it is that simple). No matter how many ways a channel represents a constituency, no matter how many explanations you have read about channels, at least from now on, it is a constituency. Please don't tell me that you never need an article. When you make a selection with any selection tool, try the storage selection command that you should know very well. Now, do you realize that you have established a channel in a * *? You can't change any part of the image without touching the channel, which is why I listed the channel as the beginning of this topic. Only by understanding the channel can we break away from the ranks of beginners and move towards the realm of masters.

Of course, I won't just tell you this, it's just my preparation for the rest. After all, experts in any field can't just see the appearance of things. But whatever you see next, please always remember what I told you above. Do you remember what it is? Yes, the passage is the constituency.

What can Channel 2 do?

In the channel, most of the information of the image is recorded, which is closely related to your operation from beginning to end. Specifically, the functions of channels seem to mainly include:

(1) indicates the selection area, that is, the part indicated in white. Using this channel, you can create precise selections, such as hair.

(2) indicates the ink concentration. This can be achieved by using the information panel. Different channels can use 256 gray levels to represent different brightness. The pure red dot in the red channel appears as pure black on the black channel, that is, the brightness is 0.

(3) indicates opacity. In fact, this is a function that we are most willing to use. Maybe you have seen a picture of Zhang Shan disappearing into the water? Have you ever envied it? Then, just remember the channel. If you love it, it will help you.

(4) color information. Try an experiment and preview the red channel. No matter how your mouse moves, there is only R value on the information panel, and the rest are 0.

Classification of three channels

As an integral part of an image, the channel is inseparable from the format of the image. Different colors and formats of images determine the number and mode of channels, which can be directly seen in the channel panel.

The channels involved in photoshop mainly include:

(1) composite channel.

The composite channel does not contain any information. In fact, it is just a shortcut to preview and edit all color channels at the same time. It is usually used to return the channel panel to its default state after editing one or more color channels individually. For different modes of images, the number of channels is different. In photoshop, channels involve three modes. For an RGB image, there are four channels: RGB, R, G and B; For a CMYK image, there are five channels: CMYK, C, M, Y and K; For images in Lab mode, there are four channels: Lab, L, A and B.

(2) Color Channel

When editing an image in photoshop, you are actually editing the color channel. These channels decompose the image into one or more color components, and the mode of the image determines the number of color channels. RGB mode has three color channels, CMYK image has four color channels, and grayscale image has only one color channel, which contains all colors to be printed or displayed.

③ Spot Channel.

Spot color channel is a special color channel, which can use colors other than cyan, magenta (some people call it magenta), yellow and black to draw images. Because spot color channels are generally used less, there are more related to printing, which I will talk about later.

(4) Alpha Channel

Alpha channel is a term in computer graphics, which refers to a special channel. Sometimes, it refers to transparent information, but it usually means an achromatic channel. This is the channel we really need to know. It can be said that all kinds of special effects we do in photoshop are inseparable from the Alpha channel. Its most basic purpose is to save the selection range, which will not affect the display and printing effect of the image. When an image is output to a video, the Alpha channel can also be used to determine the display area. If you go deeper into nonlinear editing software such as After Effects, it will be clearer.

5] monochromatic channel

The emergence of this kind of channel is quite special, which can also be said to be abnormal. Just try it. If you delete one of the channels in the channel panel, you will find that all the channels become "black and white", and the original color channels will become gray even if they are not deleted.

Four-channel editing (especially the Alpha channel in most cases)

Editing an image is essentially an editing channel. Because the channel is the place where image information is really recorded, no matter the change of color, the increase or decrease of selection area and the generation of gradient, it can be traced back to the channel.

For special editing methods, I won't introduce them here. Let's see what are the regular ones!

First of all, it should be noted that due to the particularity of the channel, it is inextricably linked with many other tools, such as masking. Anyway, we operate the channel together:

(1) Use the selection tool

Selection tools in photoshop include box selection tool, lasso tool, magic wand, text mask and selection area converted from path, including setting of different feathering values. Using these tools to edit in a channel is the same as operating on an image. All you need is a little courage.

You can use the selection tool to complete some basic operations.

(2) Using drawing tools

Drawing tools include airbrush, brush, pencil, stamp, eraser, gradient, paint bucket, blur sharpening and smearing (blur, sharpen and smear), deepen and brighten, and sponge (fade and smear).

Now it should be easy to understand the color of the channel we usually operate. When you see the white color brought by any choice, you must have an impulse to smear it with your fingers. Of course, the result of this may only change the color of your beloved display screen, but you can use tools such as brushes as substitutes for experiments. Indeed, you can create any selection area with the drawing tools at your fingertips. The only difference may be that you can't see the moving black and white lines.

One advantage of editing channels with drawing tools is that you can accurately control strokes (although not as good as sketchpad), so that you can get softer and more complicated edges. Use them practically, and you will soon like them. Every picture I make now, as long as it involves channels, more than 80% starts with brushes. Because I don't need a mass of black or white.

What I want to mention here is the gradient tool Because this tool is special. It's not that it's particularly complicated, but it's easy to be ignored. But it is particularly useful relative to channels. It is a painting tool in photoshop that I know can paint many colors at once and contains smooth transition. For the channel, it also brings a smooth and delicate gradient. It's a good idea to start here when you want to integrate yourself perfectly into nature.

(3) Use filters

The filtering operation in the channel is usually carried out under different gray levels, and the reason for using the filter is usually because we deliberately pursue an unexpected effect or just to control the edge. In principle, you can experiment with any filter in the channel. Of course, this is only when you have no purpose. In fact, most people usually have a clear desire when using filters to operate channels, such as sharpening or blurring edges to establish a more suitable choice. All kinds of situations are complicated and need to be dealt with according to different purposes, but you can try your best and you will always get something.

(4) Use adjustment tools

Particularly useful adjustment tools include levels and curves.

When you use these tools to adjust the image, you will see a channel menu in the dialog box where you can edit the color channel. After selecting the channel to adjust, hold down the shift key, click another channel, and finally open the composite channel in the image. So you can force these tools to work on the same channel at the same time.

This is certainly useful for editing channels, but it is not often used in practice, because you can create adjustment layers without destroying the most original information.

Thirdly, it is impossible for a simple channel operation to produce any effect on the image itself, and other tools must be combined, such as selection and masking (of which masking is the most important). Therefore, it is best to contact these tools when you understand the channel, so that you can know what role your carefully crafted channel can play in the image.

Five supplements

The information recorded in the (1) color channel is not strictly the whole file, but comes from the layer we are currently editing. When you preview a layer, only the content of the layer is in the color channel, but if you preview multiple layers at the same time, the color channel will show the blending effect of the layers. However, since we can only edit one layer at a time, any changes made using the color channel will only affect the currently selected layer.

⑵ When we click a channel on the channel panel for preview, a gray image will be displayed, and you can clearly see the information in the channel, but if multiple channels are opened at the same time, the channel will be displayed in color. You can open the display and cursor settings dialog box and view the Clolr channel in color item, but I believe you will eventually give up this seemingly significant change, because you can hardly find what you could have easily found.

(3) Sometimes, you set a selection area that you are very satisfied with in the channel, but when you load this selection area in the image, you are shocked: this is not the same as in the channel at all! Maybe, but don't doubt yourself. You know you didn't make a mistake, and of course photoshop didn't make a mistake. To understand this truth, we still have to start with gray scale.

Do an experiment, select an area in the new channel and fill it with 5 1% gray level; Create a new selection in the same channel, fill it with 49% gray, and finally load this channel into the image as a selection. Did you see the result? It's just that the place shows less than 50% gray, but the area filled with more than 50% gray has not disappeared and has been selected. You can think that the transparency represented by these gray levels makes the selection itself transparent. Therefore, when you load a channel completely filled with more than 50% gray as a selection, there is nothing to worry about. It is worth noting that the volume of the speaker should be turned down in advance to avoid being scared by the sound of the pop-up warning box.

(4) Do you want to create a constituency with feathering value on only one side? Try it in the article. Create a selection (use a rectangular mask to make it easier to understand) and fill it with the gradient tool. Load this channel! Remember what you saw, go back to the channel and re-edit the selection. Try a few more times and you will understand that the channel is for you! ! ! !