Photoshop about the selection of images

In the process of editing and modifying digital image, the best selection of image is the first work of the whole procedure. Only if we correctly select the parts that we need, can we modify the image in a specific way. So here, I'll start with a detailed discussion of the basic methods and techniques for selecting images in Photoshop.

Basic tools and methods of use.

Selection Tool:

Let's take a look at the general selection tools.

The first line is: rectangles, ellipses, single-line, single-column, and trim.

The second line is: Lasso, polygon sleeve and magnetic lasso tool.

Then let's look at how to use them.

Rectangle and Ellipse selection tool.

When using rectangles (rectangular Marquee Tool) and ellipses (elliptical Marquee Tool) tools, we can hold down SHIFT and drag. In this way, we can draw a square and a circle of the selection area. As we use the selection tool, we should open the Tools Options Panel, double-click the Selection tool or execute the window/show Options command.

The image above is the option panel.

Feather (feather) is used to set the selected feather range, the larger the feather value, the more blurred the selection edge, the smaller the value, the clearer the edge.

Anti-aliased (antialiasing) can be set when using the Ellipse selection tool, which can be smoothed to create a toothed edge formed by a selection.

Effect chart after feathering without feathering

There are three options in style: normal (normal) when you choose the normal, there is no limit, what you choose is what it is; constrained Aspect ration (proportional limit) If you fill 4 in width, fill in 3 in height, your chosen area will meet 4 : 3 of the height-to-width ratio; Fixed size (specify size) at this point, you have a long and wide length of your selection box, you can get a certain size of the selection box!

Single row selection tool.

Single row and Single-column (single column) tools are used to select a selection with a height of 1 pixels or a width of 1 pixels, respectively. Just click to get the selection, but because the selection is only 1 pixels high or wide, we can zoom in on the image to work better when we use it. The use of Single-line single row tools is not very frequent, but it is useful when making some drawing charts, as this is only an introduction to the selection of images, so the production of drawing lines will be introduced in detail later. In addition, in some of the entire image of the thin line can also be used to repair a single row!

Lasso type Tools.

In fact, the basic use of lasso-type tools and the first few similar, but more flexible. But I think the use of lasso (Lasso Tool) and polygonal lasso (polygonal Lasso Tool) is not very convenient. Unless you can control your hands very well, it is very inconvenient to rely on these two tools to select a certain image. Let's take a look at the magnetic lasso (Magnetic Lasso Tool) it is fuzzy square

, let's click it and move the mouse along the edges of the selected object (without holding the mouse down), and the path will automatically close to the image as if it were sucked past. This is useful when we make rough, irregular selections. In which, if there is a wrong stroke, we can press the Del button to delete, we can also click to add any trace points to help the selection positioning, to achieve a more accurate selection effect. If you press the ALT key at the same time as the selection, you can draw a straight line.

The option options for the magnetic lasso are set more, and he has more lasso width (lasso breadth), Frequency (frequency), edge contrast (edge contrast)

In the case of a small set of cable width, the selection will be more fine, but the accuracy of the cursor movement requirements are higher, and the larger value set, even if the mouse far away, the lasso can automatically paste to the image. Therefore, when we select objects and the image of the background map demarcation is not obvious

or require more accurate, we should choose a smaller nib; instead, choose a large nib when choosing a clear edge image such as the above. Frequency is used to automatically place the stroke frequency, this value is too large and too small will affect the normal selection, generally set to the default value (57) can! Edge contrast used to determine the impact of the image edge on the selection, we can use it to adjust the sensitivity of the magnetic lasso, the high value is suitable for the edge of the strong contrast with the surrounding, while the low value is suitable for the detection of low contrast edge.

Edge contrast set to 1 o'clock edge contrast set to 90 o'clock

Obviously, in such a strongly contrasting image, the effect of using high values is better than low values.

Magic Wand Tool.

The Magic Wand tool (Magic Wand) is selected based on the color of the image clicked, and is considered to be the most powerful in all selection tools. Because when you choose a region where the image is complex but the color is similar, it is often only a matter of choosing an incredibly perfect graphic. But its use is very convenient, here I only introduce one of its parameters. Tolerance (tolerance), this option is used to set the value from the click of the area began to spread the color difference rate of the selected image, when you adjust the hour, for the surrounding image Color matching degree is high, conversely low.

Say this for the use of basic selection tools. Then we'll talk about some advanced applications and techniques.

Advanced applications and techniques.

A lot of friends say to choose the image in Photoshop is too difficult, sometimes the image is too complex, that is, the use of magic wand may not be able to achieve the desired effect, now let us look at the following two pictures, the left is the original image, and the right picture is removed

The blue image, obviously, the right side of the temple and the surrounding environment contrast is larger than the original, so we can do a better job of selection. The whole process works like this: Open the original image-decide to select the area-go into the Channels Control Panel (windows/show Channels)-Remove and observe an item from red, Green, and blue in the panel-use the Magic wand and other selection tools to select the work.

But sometimes, regardless of which color is deleted, the selection of the image is still not very good, this is what we need to use another method. In Photoshop, menu commands provide the most comprehensive functionality, and the work of a constituency is no exception. Let's go to the Select/color range (color range) and get the following dialog box. The Select Drop-down list is used to select the color

Way: Sampled Colors (sample color) is the selection of the color of the image by the eyedropper, as well as the red, Blue, and green options for selecting a particular color in the image, as well as the highlights (high light), Shadows (shadow), and so on selected for the tone of the image. After selecting the selection (select range) option under the image, you can preview to the selected range, where white represents the selection and black represents the unselected region. When image is selected, we will not be able to see the selection, but we can preview the entire image. (Note: We can switch between these two states by ctrl) You must have found three little straws under save, what is this for? The first straw is used to select the color, the second has a small plus, of course, is used to add another color unit, and the last one with a minus sign is to remove a selected color unit. fuzziness (color tolerance) used to specify the color range of selected colors, it and the magic wand in the same tolerance, to choose a small range of colors, the number should be small, conversely, if the scope of large, the number can be adjusted. Finally, let's look at the selection Preview (Selection preview) at the bottom of the panel, normal is a normal state, nothing to say. Other four items: Grayscale (grayscale): According to the image displayed under the gray channel; black Matte (Dark Miscellaneous): Black as the backplane, selected areas to display color; white Matte (mixed): White as the backplane, selected area to display color; Quick Mask (Quick Mask): Displays a selection using the current mask settings. When we use these items, we'd better select the image option, which is more convenient.

Finally, let me tell you a special feature in Photoshop: Image/extract.

Let's take a look at the tool bar in the first one:

A:edge highlighting tool (edge fluorescence)

B:fill tool (filled)

C:eraser Tool (Eraser)

D:eyedropper tool (Straw)

E:zoom tool (magnifying glass)

F:hand Tool (MOBILE)

We have B, C, D, E, F Five are more familiar with, and the first edge of the fluorescence seems to be a new thing, in fact, this is a very good tool, we choose the following picture, and to select the outline of yak, but to the yak on the fine hair can also be better elected seems to have some difficulties, But let's use the edge fluorescence to draw a fluorescence along the Yak's contour, as shown on the left. Then click the Fill tool in the selected contour to get the middle effect, where green grass is not only the selected area, the last click Preview, get the right graph effect preview, if satisfied click OK, or you can make a new selection.

How about that is not more convenient? Well, for the chosen method, there are a few ways to discuss the masks and paths later in detail.