Channel Principle of PS – Channel Tutorial

The channel principle of ps 1. What is a channel
When you see this question, if you feel a headache, then—-, no, no, the first thing you should do
Go get the painkillers, but be thankful you’ve gotten to this point, because it gives you a good chance to master the passage once and for all, and perhaps give you a headache for the last time.
Whether it is in various computer magazines or online media, various articles about Photoshop channels appear in endlessly, but so many people are still confused? To a large extent, we should not blame our readers, because we have also been confused at times; of course, we cannot blame our authors, I believe they really tried their best. From my point of view, the key issue should be the link between the author and the reader, right? In other words, the author’s clearer ideas must be explained from the reader’s vague perspective. The more careful and professional the explanation is, and the more abstract and profound the passage is told to them, the easier it will be for people to give up. On the contrary, if you give readers a vague explanation first (even if it is not actually accurate or even correct), they will be more likely to accept it. After all, we don’t need everyone to understand every technical detail of Photoshop. Be clear, otherwise, everyone will become a photoshop engineer!
Do you understand what I mean? Yes, I’m talking about: channel simplicity. So, what is a channel? A passage is a constituency, so to speak.
It sounds very simple (actually it is that simple), no matter how many ways a channel represents a selection, no matter how many explanations you have seen about a channel, at least from now on, it is a selection. Don’t tell me you’ve never needed a channel. When you make a selection with any selection tool, try the Save Selection command which you should know very well. Now, do you realize that you have successfully created a channel? You can’t change any part of the image without touching the channel, which is why I listed channels in the first place in this topic. Only by understanding the passage can you leave the ranks of beginners and move towards the realm of “lonely seeking defeat”.
Of course I won’t just tell you this, it’s just a preparation for the following content. After all, a master in any field cannot only see the appearance of things. But no matter what you read next, please always remember what I told you above. Do you remember what it was? Yes, the channel is the constituency.
2. What can the channel do
In the channel, most of the information of the image is recorded (sometimes I suspect it is all). This information is closely related to your operation from beginning to end. Related. Specifically, the main functions of the channel are:
⑴ Represents the selection area, which is the part represented by white. Using channels, you can create precise selections like hair strands.
⑵
Indicates the ink strength. You can appreciate this by using the Info panel. Different channels can use 256 levels of gray to represent different brightnesses. A pure red point in the Red channel is displayed as pure black on the black channel, that is, the brightness is 0.
⑶
Indicates opacity. In fact, this is the function we are most happy to use. Maybe you’ve ever seen a picture of a mountain fading into water? Have you ever been envious? So, just remember the channel, if you love it, it will help you.
⑷ Represents color information. You might as well experiment and preview the Red channel. No matter how you move the mouse, there will only be R value on the Info panel, and the rest will be 0.
⑸
Hehe, hehe, you can share what I have learned, show off your appearance, and earn some money.
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3. Classification of channels
As a component of the image, the channel is related to the image The format is inseparable. The difference in image color and format determines the number and mode of channels, which can be seen intuitively in the channel panel. The main channels involved in Photoshop are:
⑴ Compound Channel
The Compound Channel does not contain any information. In fact, it is just a shortcut for previewing and editing all color channels at the same time. It is usually used to edit one or more colors individually. After passing, the channel panel returns to its default state. For images in different modes, the number of channels is different. In Photoshop, for an RGB image, there are three modes: RGB, R, and RGB. There are four channels of G and B; for a CMYK image, there are five channels of CMYK, C, M, Y, and K; for a Lab mode image, there are four channels of Lab, L, a, and b. .
⑵ Color Channel (Color Channel)
When you edit an image in Photoshop, you are actually editing the color channel. These channels decompose the image into one or more color components. The mode determines the number of color channels. The RGB mode has 3 color channels, the CMYK image has 4 color channels, and the grayscale image has only one color channel. They contain all the colors that will be printed or displayed.
⑶ Spot Channel
The spot color channel is a special color channel that can use colors other than cyan, magenta (some call it magenta), yellow, and black to draw images. Color channel is used by ordinary peopleLess and more related to printing, so I will leave it to the content later.
⑷ Alpha Channel (Alpha Channel)
Alpha channel is a term in computer graphics, which refers to a special channel. Sometimes it refers specifically to transparent information, but usually it means the “achromatic” channel. This is the channel we really need to understand. It can be said that all kinds of special effects we create in photoshop are inseparable from the Alpha channel. Its most basic use is to save the selection range and will not affect the display and printing effects of the image. . When the image is output to video, the alpha channel can also be used to determine the display area. If you’ve ever been a little bit into non-linear editing software like After
Effects, you’ll have a better idea of ​​what I’m talking about. But because
the video is not directly related to what I am going to talk about now, I will ignore it for now.
⑸ Monochrome channel
The generation of this channel is rather special, and it can also be said to be abnormal. Try it, if you delete one of the channels in the channel panel, you will find that all channels become “black and white”, and the original color channels become grayscale even if they are not deleted.
Having said all this, my purpose is not to confuse you. If you already know it clearly, that’s the best; if you don’t understand it, it doesn’t matter, keep reading or just stop thinking about it. In the end, as long as you know how to do it, you will succeed.
4. Channel editing (in most cases, it refers specifically to the Alpha channel)
It has been mentioned when talking about color channels. Editing of images is essentially just editing of channels
>edit. Because the channel is where image information is actually recorded, any change in color, the addition or subtraction of selections, or the generation of gradients can all be traced back to the channel. Now, it’s time to apply what you’ve learned.
As for the special editing methods, I won’t introduce them here. Let’s take a look at the conventional ones!
First of all, it should be noted that due to the special nature of the channel, it is inextricably linked to many other tools, such as masks. So here, the so-called conventional method is a relatively common editing method for channels, and it can also be considered as a simple selection method. We’ll cover the rest when discussing other tools.
Back to business, let’s operate the channel together:
⑴ Use the selection tool
The selection tools in photoshop include the mask tool (Marquee), the lasso tool (Lasso), and magic Magic Wand, Type Mask, and selections converted from paths, etc., including settings of different feathering values. Editing in a channel with these tools is the same as working on an image, all you need is a little courage.
Using the selection tool can accomplish some of the most basic operations, but if you ask me to give an exact example, it would be a bit difficult, because I really can’t remember any part of my recent work that just uses selection. Tools for editing channels. Perhaps when making slight changes to a constituency that has already been established through other methods? This method is really so basic that you have to understand it but you are almost unaware of its existence.
⑵ Use drawing tools
Drawing tools include Airbrush, Paintbrush, Pencil, Stamp, Eraser, Gradient, and Paint bucket
Bucket), blur sharpening and smudging (Blur, Sharpen, Smudge), burn dodge and sponge (Dodge, Burn, Sponge).
Now it should be easy to understand the color problem of the channels we usually operate. When you see the white color from any of the options, you should feel the urge to apply it with your fingers. Of course, the consequences of doing this may only change the color of your beloved display screen, but you can use tools such as brushes as an alternative to experiment. I believe the consequences of doing this for the first time will be exciting. (If you say no, then you promise me that the color you are painting with is not the same color as the color where you are painting). Indeed, you can create any selection area with any drawing tool you can find. The only difference may be that you can’t see those black and white lines that are constantly moving.
One advantage of using drawing tools to edit channels is that you have precise control over your strokes (although not as well as a drawing tablet), allowing you to get softer and more complex edges. Give them a try and you’ll quickly fall in love with them. Now every picture I make, as long as it involves channels, more than 80%
starts with a brush. Because I don’t need a ball of black or a ball of white.
What I want to mention here is the gradient tool. Because this tool is quite special. It’s not that it’s particularly complicated, but it’s that it’s easily overlooked. But it is particularly useful for channels. It is the only painting tool in Photoshop that I know of that can paint multiple colors at once and contains smooth transitions. For channels, it brings smooth and delicate gradients. I think when you want to perfectly integrate yourself into nature, this is a good idea to start.
⑶ Use filters
Someone once asked me what makes a good piece of art. I told him at the time that they were works that perfectly combined natural elements with man-made creations. In essence,I have also been thinking about this issue for a long time.
Like most people, I firmly believe that human creativity and imagination are unlimited, but I also know that this does not mean that one person can imagine everything. Sometimes, it’s not a bad thing to isolate yourself and let photoshop do your work. It’s actually a pretty fun way to do it.
Filter operations are usually performed in channels with different grayscales. The reason for using filters is usually because we deliberately pursue an unexpected effect or just to control the edges. In principle, you can use any filter in the channel to experiment. Of course, this is only when you don’t have any purpose. In fact, most people usually have a clear desire when using filters to operate channels, such as sharpening. Or blur the edges to create a more suitable selection. Various situations are more complicated and need to be handled accordingly according to different purposes, but you can try it and you will always gain something.
⑷ 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 on the dialog box, where you can select the color channel you want to edit. When you select the channel you want to adjust, hold down the shift key, click on another channel, and finally open the composite channel in the image. This way you can force these tools to work on a channel at the same time.
This is certainly useful for editing channels, but is actually not commonly used because you can create adjustment layers without destroying the original information.
Actually, if you didn’t understand what a channel was before, you should understand it now
In the final analysis, the understanding of the passage is just a matter of perception, and the epiphany may only take a moment.
I would like to emphasize again that pure channel operation cannot produce any effect on the image itself. It must be combined with other tools, such as selection and mask (mask is the most important among them), so when understanding the channel It’s best to connect with these tools to know what role your carefully crafted channels can play in an image.
5. Is there anything else you want to say?
⑴
The information recorded in the color channel is not strictly speaking from the entire file, but from the layer we are currently editing. When previewing one layer, there is only the content of this layer in the color channel. However, if multiple layers are previewed at the same time, the color channel displays the mixed effect of the layers. But since we can only edit one layer at a time, any changes made using the color channels only affect the currently selected layer.
⑵
When we click a channel on the channel panel and preview it, a grayscale image will be displayed. You can clearly see the information in the channel, but if you If multiple channels are opened at the same time, the channels will be displayed in color. You can open the Display and Cursor Settings dialog box and check the Color
channel in color item, but I believe you will eventually give up on this change that seems quite significant at first, because you can hardly find what you could have easily changed. Easy to find stuff too.
⑶
Sometimes, you create a selection area in the channel that you are very satisfied with, but when you load the selection in the image, you are shocked: it is not the same as the one in the channel. Well! Maybe, but never doubt yourself, know that you didn’t make any mistakes, and neither did Photoshop. To understand this truth, we still have to start with grayscale. (Hey, it’s all the grayscale that’s to blame.)
As an experiment, select an area in a new channel and fill it with 51% gray; create a new selection in the same channel and fill it with 49% gray. Fill, and finally load this channel as a selection in the image. Did you see the results? Only the area filled with less than 50% gray is displayed. In fact, the area filled with more than 50% gray has not disappeared. It is also selected. You can think that the transparency represented by those grayscales makes the selection itself Also made transparent. Therefore, when you load a channel that is completely filled with more than 50% gray as a selection, there is nothing to worry about. What is worth noting is to turn down the volume of the speaker in advance to avoid the pop-up warning box. The sound just scared me.
⑷
Want to create a selection with feather value on only one side? Try it in the channel. Create a selection (use a rectangular mask to make it easier to understand) and fill it with the Gradient Tool. Load this channel! Remember the effect you see, go back into the channel and re-edit that selection. Try it a few times, and you’ll better understand what the channel does for you.
⑸ Photoshop5 supports up to 24 channels, but there seems to be no limit in 6.0. But it seems that there is no need to use so many channels, right?
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