The first knowledge of Photoshop layers

If we want to change the blue ball position above the lower left figure, we need to create a selection that matches the size of the ball, which is not difficult, and you can use the Elliptical marquee tool to create a positive round selection (you can enlarge the image by clicking the Space _ctrl_). You can then use the Move tool to move the contents of the selection, as shown in the following illustration, the white arrow represents the direction and destination of the mouse drag, which will be used in future legends to represent the drag trajectory.

But after moving, the place where the ball was originally produced a blank area, as shown on the right. This is because the original content is "dug away", so Photoshop use the background color to fill the vacancy, that is, depending on the background color, fill the area of the color is also different. Obviously this is destroying the image.

Who is responsible for destroying images? Strictly speaking is us, because that hole is not what we dug, hehe. The real reason is that all the images, or all the pixels in the picture, are all in the same layer, inseparable from each other. So moving pixels in one place creates a vacancy. It's like digging a piece of paper is bound to leave a hole. This is very inconvenient for the creative design process that is full of variables. If you need to change a part, you have to do it all over again.

Now understand why the real life of the calligrapher is not ordinary people can be, because the text must be a pen in the end coherent, can not be modified halfway, need to rely on a large number of long hours of practice to have such a driving force.

After using the layer, you can separate the ball from the background and store it on a different layer so that when you move the ball, it will not cause damage to the background, as shown on the left. The bottom right figure is the appearance of adjusting the front and back layer palette. From there you can see that the Layer palette is no longer a single background layer.

Layers are important in our design process. Beginners should pay special attention to layers of layer problems, because levels can cause occlusion. In addition, the layer blending mode is a difficult problem, according to our current knowledge level, it is more difficult to understand the layer blending mode. In fact, even professional and skilled users may not be proficient. In the actual use of the people on their own to test the effects of a variety of mixed mode. Later to understand the specific principles.

Now drink saliva, play the spirit, the content of this lesson "a little more". The content of the layer blending pattern will be systematically studied in the following course, and only a few tries in the practice of this section.

In the previous course we had a few and layers of the ball, now to formally learn the layer. Layers are an important part of Photoshop. Layers have also become one of the basic concepts of all image software. Similar concepts also existed in illustrator and GoLive.

What exactly is a layer? What is the meaning and function of it?

For example, we draw a person's face on the paper, draw the face first, then draw the eyes and nose, then the mouth. After the painting, I found the position of the eye was crooked. Then only wipe out the eyes and repaint, and the face to make some corresponding repair. Of course it's inconvenient. In the design process is also the case, rarely a molding of the work, often after a number of changes to get more satisfactory results.

Imagine, then, that if we were not directly drawn on paper, we would put a layer of transparent plastic film on the paper, and the face would be painted on this transparent film. Finish the painting and then lay a layer of film to draw your eyes. and a picture of the nose. The following figure, the face, nose, eyes divided into three transparent film layer, the final composition of the effect. The finished product after this completes, and the previous piece in the visual effect is consistent.

Although the visual effect is consistent, but the work of the layered painting has a strong modifiable, if you feel that the eyes are not correct, you can move the eye of the film alone to achieve the modified effect. You can even discard this film and paint your Eyes again. The rest of the nose and other parts of the face are unaffected because they are painted on different layers of film. This way, greatly improves the convenience of late modification. Most likely to avoid duplication of work. Therefore, it is advisable to make the image layered.

We can also use the concept of "transparent film" like this in Photoshop to process images. You can view and manage layers in Photoshop in the Layer palette 〖f7〗. The Layer palette is one of the most frequently used palette, usually merged with the channel and the Path palette. At least one layer must exist in an image.

If a new image is selected with a white or background color, a background layer exists in the new image and a locked flag is present. The following is the left figure. If the background selection is transparent, a layer named Layer 1 appears. The following is the right figure.

Now we're going to use layers to draw a simple human face. Create a new image 〖ctrl_n/ctrl_ double-click the blank area, size 400x300 or custom, RGB mode 8-bit channel. The background content is white.

Then open the Layer palette 〖f7〗, where you see a layer with the name "background" in it, and a locked flag on the top right of the layer. Similar to the left figure.

Layer panels can display thumbnails of the content in each layer, which makes it easy to find layers. The default is a small thumbnail that you can use in or out of, or you can close thumbnails. By right-clicking on a blank area of the layer palette (that is, where no layers are displayed), right-click to change the thumbnail size, as shown on the left. You can also click on the Small triangle button in the upper right corner of the layer palette and select "Palette Options" in the pop-up menu. The following is the right figure. The "cut thumbnails to layer boundaries" and "cut thumbnails to document boundaries" option below are the way thumbnails are displayed, and you can now select the following as the left image. Note: CS and earlier versions cannot select thumbnail display mode.

Even small thumbnail, Occupy layer palette space is also a lot of, sometimes instead of reducing the use of layer palette, so in the actual use of small significance. When you are proficient, it is recommended that you close the thumbnail to get a larger layer palette space to use. Let's use the small thumbnail to see the way below.

Now we learn the layers by using the following practical procedures, create a white background image with a 400x255 (note that the unit is pixel, and set yourself), and then create a new layer to paint the face. The way to create a new layer is to click the button below the Layer palette (the red arrow at the bottom left) to see that the Layer palette has a layer called layer 1, so that the layer is already built. In layman's parlance, a layer of transparent film has been covered.

The new layer created in this way is transparent, and note that "Layer 1" in the thumbnail shows the gray and white squares. This block pattern we have seen before, is a transparent part of the image of the representation method. The transparent part, where no pixel exists, is an "empty" state, just like a transparent glass without any pattern.

Hold down the ALT key and a dialog box appears in Layer 1 on the Layer palette, as shown in the figure below. You can change the layer name and color marker. The role of color markers is to make the layer name in the palette appear prominent, and the contents of the layer is not related to the content of their own preferences to choose any color tag. Here we change the name to face and change the color to red.

If you want to change only the layer name, double-click the layer name directly in the Layer palette (note that you do not double-click an area other than the layer name), the input box appears, as shown on the right. You can use the Chinese naming layer.

We use the ellipse 〖u or Shift_u〗 in the shape tool to draw, note that you must use the third "fill Pixel" drawing method (red arrow). Other settings refer to the following figure. It must be set correctly here.

Choose a foreground color that you like to draw an ellipse in the face layer as a cheek. Before painting, be sure to pay attention to the current selection of the Layer palette is the face layer, after painting from the face layer of the thumbnail can see the approximate shape. The following is the left figure. If the previously selected layer is a background layer, the ellipse is drawn to the background layer. Be careful not to make such a mistake.

A new layer is named Eye, and the color is labeled green. Select a circle that represents the eyes in a different color than before. Hold the SHIFT key while drawing to draw a positive circle. The following figure.

Thumbnails can be used to determine and select layers, but some of the finer parts are difficult to see in the thumbnail, such as the thumbnails in the eye layer below. This is because the proportions of the two thumbnails correspond to the actual proportions of the two layers in the image. To improve the readability of a layer thumbnail, you can use a larger thumbnail. However, large thumbnails also increase the height of the layer palette and reduce the efficiency of the layer palette, so in order to make it easier to find and choose, you should name the layers with the appropriate names, and use color markers to distinguish them. In addition, you can use the "cut thumbnail to Layer boundary" method (CS and earlier versions are not available), as shown below, the thumbnails will be scaled to the content in their respective layers instead of the whole image as a scaling criterion. The specific display methods can be based on their preferences and practical needs.

Is this face a bit like an egg? Haha, we do not feel that it is simple, because at this time we are trying to use simple graphics to explain the layer, now contact with too complex image will make everyone dazzled. After mastering the knowledge not to be an egg, even if it is an atomic bomb we can draw it. Besides, Leonardo da Vinci was not the beginning of the painting of eggs.

Now looks like a one-eyed dragon, should be the other side of the eye also fill the picture is complete. But there's a problem, two eyes should be the same size, how can you draw a circle of the same magnitude as before? This time you can copy existing layers to achieve your goal. We can copy one of the eye layers.

The way to copy a layer is to drag the layer onto the new Layer button below the Layer palette. This will result in a new layer called "Replica". The color flag of the layer is also copied. The following is the left figure. You can also hold down the ALT key to drag the layer. The following figure.

When the layer is selected, it is copied through the layer _ new _ through copy layer 〖ctrl_j〗, but the color flag is not copied. The layer _ Copy Layer command allows you to copy layers to other images, provided that you have multiple images open in Photoshop, you can select the name of the image you open in the target, and you will create a new image if you select New (the right below).

Here is a clear picture of the relationship between the layers: the layer is from an image, and there can be multiple layers in an image.

After the copy, see the picture is still only one eye. This is because this method copies the layer and the original layer position exactly the same, is overlapping. At this point, select the eye copy layer in the Layer palette and drag in the image using the Move tool 〖v〗. Hold down the SHIFT key while holding the drag in a horizontal, vertical, or 45-degree direction. The following is the left figure. The options for the Move tool in the public column are two options: Automatically select the layer, display the bounding box, and here we'll close all of them. Their role will be described later.

In addition, in the course of the move, there may be the pink lines of the figure below, which are smart guides that make it easier for us to observe the effect of the layer alignment, which will be introduced later in this article, but not now. If you feel unsightly, you can use the view _ display _ Smart guides to close.

Note that the move tool is moved by the current selection layer in the Layer palette, which has no relation to the position of the mouse in the image. In other words, as long as the eye layer is selected in the Layer palette, the eye layer will be dragged regardless of whether the move tool presses the drag anywhere in the image. Drag the eye layer even if you put the cursor over the face or other layers of the image. Below the right figure, press the mouse at several red dots to drag the eye layer. However, the prerequisite is that the Auto Select layer option in the public bar of the move tool must be turned off.

In addition, when using the Mobile tool, you can use the keyboard around the next key to move the layer, the use of the direction of the key to move the way is also known as "light Move." The distance between each nudge is different depending on how the image is displayed, and if the 100% zoom is 1 pixels each time, hold down the SHIFT key and move 10 pixels at a time. The smaller the display ratio, the greater the actual distance of the light shift.

It's important to keep in mind that any action we make on a layer should be targeted and the selected layer can be moved or some other operation. For example, if you want to draw with a brush tool, you must first specify which layer you want to draw. Choosing the wrong layer is a common mistake for beginners to make. Or forget the concept of hierarchy, the part that should be layered made on the same layer. It is only after a few steps that the original error is detected. For example, before we finish painting the face without a new layer, and the eyes are then painted on the face of this layer. This is wrong, but at this point in the image but can not see, because at this time the screen effect and layering production is the same. To copy the eye layer, you will find the error, because the copied layer is also a face plus an eye. From now on, we must have the idea of layers in our hearts. Just like to remember to eat with chopsticks in the same dish.

Although you can select multiple layers in Photoshop at the same time (CS and earlier versions can only select one layer), the move tool can also move multiple layers at the same time, but drawing class tools such as brushes are used only in one layer, such as the possibility of drawing images simultaneously in the face and eye layers. Filters that you want to learn later can only work on a single layer. Keep in mind, therefore, whether the currently selected layer is correct. The way to select a layer is to click on the corresponding layer on the Layer palette.

In addition to copying layers using the above methods, you can also use the Move tool to replicate directly in the move. By selecting the Move tool, holding down the ALT key in the image, the cursor changes from to, indicating that the mobile copy function is started, and the mouse is dragged to copy the new layer (the ALT key can be released after the mouse is pressed). The following figure. Hold down the SHIFT key at the same time to maintain the level (hold down the whole process).

In fact, in the layer palette you can also hold down the ALT key to drag the layer to complete the copy, the following right figure.

Now let's define the relationship between the layer and the image: The image is the overall effect created by the creation of a new command (or open an existing image), which is synthesized by multiple (at least one) layers. It has dimensions and boundaries.

And the layer actually has no boundaries, can contain larger than the entire image content, the simplest proof is: You can move the eye or face layer outside the image edge to move back. However, parts that are outside the image size range will not be visible. This is like the relationship between the scenery and the camera, the photos taken can reflect the local scenery, but does not mean that the actual scenery is only so many photos.

You can assume that the size of each layer in an image is the same, because it is infinitely large. Only the pixels that are contained in different layers may be different. The so-called pixel difference refers to the size or color of the image in the layer. For example, the number of pixels in the face layer above is more than the eye layer. And we copied the two eye layers, the number of pixels and color are the same. If you change the color of one of the eye layers, the pixels of these two layers are the same number and the colors are different.

We can experience it through experiments, first select the eye layer, set the overall opacity of the layer to 9% (or smaller) in the Layer palette, and then use the Move tool to 〖v〗 the position of the eye layer in the image by right-clicking, and there is no eye layer in the list of layers that appear. The following is the left figure.

Now press the new button below the Layer palette to create a new layer (level doesn't matter) set the foreground color to black 〖d〗, and then select the Pencil tool 〖b/shift_b〗, set the opacity of the pencil to 9% in the public column (red Arrow below), 30 pixels in diameter, and point to the new layer. This shows a slightly gray circle (it should be called a dot), then switch to the Mobile tool 〖v〗 on the circle right click on the list of layers appears no new layer name, and at this time the opacity of the layer is 100%. The following is the right figure.

Now to test everyone, the following figure, in the same transparent layer, divided 3 times to draw 3 circles, transparency is 9%, 9%, 10%. 22 intersecting finished glyph arrangement. So, using the Mobile tool to right-click at 123,456 points, which points will appear in the layer's name, which points will not appear? The answer is at the end of this section. Please continue to learn the following after completing the subject.

We already know that by clicking the right button in the image with the mobile tool, Photoshop will judge the layer that appears in the list, which is the point at which the mouse clicks (known as the mouse point) to determine the pixel status of each layer on this mouse point (that is, the opacity is equal to 9% or greater than 9%). This creates a phenomenon where if the content of the layer is hollow, that is, surrounded by pixels and the middle part is transparent, click in the transparent position and the layer will not appear in the Layer list.

Let's do an experiment. First you copy the eye layer again and move underneath (you can use the Move tool to press the ALT key to move the copy), and then use the Rectangular marquee tool to select a piece in the middle and delete the contents of the selection "edit _ Clear" 〖delete or Backspace〗, and then cancel the selection 〖ctrl _d〗. Then click the right mouse button in the deleted area (Figure 1 below) to see if the copied eye layer appears in the list of layers. The approximate process is shown in the following figure.

Remember before in the school to do health, we put the classroom inside and outside every corner are swept polished, the results of the Health Inspection Unit with hands to touch the top of the classroom door, that is one of us who did not notice the place. No matter how clean the other place, or to check the hands of the inspection team, the place is rated unqualified. Just as the layer selection is the same as clicking on the mouse.

As I said before, in a layer where there is no pixel is transparent. is a state of nothing. Photoshop is transparent with the gray and white square squares, if you want to change the color and size of the box, you can use the edit _ preferences _ transparency and gamut 〖ctrl_k,ctrl_4〗 modified. It is recommended that you use the default settings.

In addition to the above method of clicking the right button when using the Mobile tool, there is a way to select the layer more quickly. It can be called "the speed of light choice".

Also, when using the Move tool 〖v〗, hold down the CTRL key and click directly in the image, then the top-level layer on the mouse point is selected. The equivalent of clicking the right button and then selecting the highest level in the list. The following is the left Figure 3 Place, hold down CTRL click 1 will select the eye layer, click 2 will select the face layer, click 3 will select the background layer. Holding down the CTRL and SHIFT keys simultaneously selects multiple layers ().

Note, however, that this method is not valid for layers with opacity below 50%. The 50% here is the same as the 10% mentioned above. One is that the layer's overall opacity is set below 50%, or the opacity of the pixel itself in the layer is less than 50%. Please note the section on the opacity that follows.

This method of selecting layers should be the most commonly used in practice, but it has limitations, and if a higher layer of content completely obscures a lower layer, then the lower layer cannot be directly selected in this way. You can only use the previous two methods to select.

Also, if you open auto Select Layer in the options in the Move tool's public bar, it is equivalent to holding down Ctrl-click As previously mentioned. You can select a layer without holding down the CTRL key and clicking directly in the image. However, in practice, it is often easy to cause misoperation, so it is recommended that this feature be turned off. When you open this item, you can decide whether the Auto select group is turned on, and its role is to select a layer group. The content for the layer group will be learned later in this lesson.

Show transform controls option we will introduce later, here you can try first. It is recommended that you turn off this feature in peacetime. The following is the right figure.

About the selection of layers Finally, note that Photoshop can allow (CS and earlier versions do not allow) No one layer is selected, we can hold down CTRL click on the layer palette to the currently selected layer, so that no layer is selected. The following is the left figure. If you use the Move tool at this point, you will receive an error in the right image below.

When using the Mobile tool, hold down the CTRL key, you can use the mouse to drag out a selection box in the image, all the layers that touch the selection box will be selected, as shown below.

Note that the start position of the drag, not in the "nose", "eye copy", "Eye", "face" layer has the presence of pixels, otherwise the selection box will not appear and move the layer directly. Although there are also white pixels in the background layer, the specificity of the background layer allows this to be done. If the start point of the selection box must be in the position of the "face" layer, you need to lock the layer first. The contents of the lock will be covered later in this lesson.

In practice, you should use the Mobile tool to select a single or multiple layers, this method does not pass the layer palette to improve productivity. One trick to note here is that when you have selected multiple layers at the same time, holding down CTRL and clicking on one of the layers, you cannot select it individually. For example, we also select the "Eye" layer and the "face" layer, then if you want to select the "eye" layer, hold down CTRL click it is invalid, still maintain the selection of two layers of the state. Of course, we know that you can click the face layer by holding down CTRL and shift to deselect it, but if there are many layers selected at the same time, click to deselect them individually. So this theoretical approach is not practical.

A more practical approach is to hold down CTRL and click elsewhere in the image (areas other than the selected layer) so that either the other layer is selected or no layer is selected. Then hold down CTRL and click on the "Eye" layer to select it individually. This operation we should do more exercises, we suggest that in the full screen without adjusting the status of such layer selection exercise, after skilled can greatly improve the efficiency of the work.

Now answer the question mentioned earlier.

The points that do not appear in the layer name are: 1, 2. Because the pixel opacity in both places is less than 10%. The opacity at 3 is 10%, so it appears.

4 is made up of two 9% circles, in other words, this place is painted two times by a 9% brush, and its opacity should be 17%. Think about 5 and 6 in this way, their opacity is certainly higher than 9%, and therefore will appear.

See here Everyone may have a question: how do you know that two 9% will get 17%? How much will it continue to accumulate? Here is a list of the first 4 times the opacity superposition formula, we can find the law. This formula does not need to delve into, even if completely do not understand also does not affect our next study and use.

1:9%

2:9%+ (1-9%) x9%=17.19%

3:17%+ (1-17%) x9%=25.19%

4:25%+ (1-25%) x9%=31.75%

From here we want to realize that even in the same layer, the opacity of the image may be different. So it's not possible to think of the entire layer because one place clicked without a list. As mentioned earlier I had because the top of the door is not clean on the same as health unqualified, is a sweeping approach, is wrong.

In addition, you can switch the information palette to an opacity mode (the red arrow at the bottom left) to see the opacity of the mouse position in the image. Note that the values shown here are for the overall image, not for a layer. So if you have a background layer, no matter how you move, you can see only 100% of the value, in which you see the correct opacity value, you need to hide the background layer (close the background layer of the eye flag), the following right figure (because the opacity is too low so the image is not obvious).

In future operations, if you only want to view the opacity information for a layer, you should hide all other layers, especially those that overlap with their pixel positions.