As you were convinced at performance of exercise of the previous section, to select the necessary area of the image sometimes difficultly enough and long. At the same time at passage to editing of other area the previous selection disappears. In real operation often there are situations when the same selection is necessary for using at different stages of editing. Therefore in Photoshop function of saving of selection then it it will be possible to load and activate, produce with it arithmetical actions is provided, to modify its form. This saved selection name a mask. It is possible not only to include masks in document composition, but also to transfer from one document to another.

The mask represents the halftone image which size is automatically saved equal to the size of the main image in the document. For example, the selection shown on fig. 3.84, д, in the form of a mask is represented how on fig. 3.84. As a mask — the halftone image, on it it is possible to draw, changing thus the form of selection stored in a mask. The mask exists in the document as the additional channel. When you activate a mask, it turns to selection. White areas of a mask become selected, gray — partially selected, black — not selected. The shade of gray is proportional to a level выделенности areas.

As it was already told, the mask is stored in a channel type. For operations with channels palette Channels (Channels) is used:

1. Open the edited variant of the document Basketball.jpg.

2. Select a background (for this purpose enough one click by a magic wand).

3. Pass to palette Channels (Channels) (fig. 3.85), click on the button of saving of the channel with help Save selection as channel (to Save selection in the channel)

4. In a palette there will be a new channel. Black the masked areas, white — selected are marked. To the channel name Alpha 1 is automatically appropriated.

5. Cancel selection. Then bring the cursor to a line of alpha channel and click on it at pushed CTRL key. It is possible to load also alpha channel click on its line, and then — on the button of loading with help Load channel as selection (channel Loading as separation). Selection again appeared, the channel is loaded as selection.

6. Again cancel selection in the document.

7. Click on a line of alpha channel, now in a document window the alpha channel (fig. 3.86,) will be visible only — it is active.

8. Without canceling activity of alpha channel, click on an eye tag in a line of the combined channel. Now in a document window there was visible a image, and over it in the form of a red translucent film the alpha channel is shown. It is a mode of superimposing of alpha channel (fig. 3.86,).

9. Make double click on a line of the channel. In window Channel Options (Property of the channel) (fig. 3.87) change a channel name on Floor. At desire by means of switch Color Indicates (Colour to show) it is possible to change the circuit of display of the masked and selected areas. Position Masked Areas (the Masked areas) is by default active, i.e. by color (black or red) the masked areas are shown. Delivering the switch in position Selected Areas (the Selected areas), you force the program to show color the selected areas.

10. In the course of operation conveniently that in a mode of superimposing color of alpha channel was contrast in relation to colors of the image. So, if in it prevail red tone, color of the channel is good for changing, for example, to the green. For this purpose click in the field Color (Colour) and select the necessary color from window Color Picker (a color Choice). In the field Opacity (Opacity) is defined opacity of the channel in a superimposing mode.

11. For duplication of the channel it is enough to drag of it to the button of creation of the channel with help Create New Channel (to Create the new channel). Double alpha channel Floor. A copy name Ball (fig. 3.88).

You ask, what for to see alpha channel in the image? Certainly, that it to edit.

1. Activate alpha channel Ball. You can draw on it, as if this normal image. All changes in the channel are changes in selection which will be made on its basis.

2. Draw white color. Certainly that appearance of the channel changes-in it there are white (selected) sections. Drawing by white color expands selection. Drawing black color, you increase the black (not selected) areas.

3. Select worker green color then it will be transformed in gray with appropriate brightness. In the channel it is possible to work only in shades of gray, after all the channel is a halftone image. Draw the selected gray shade. Areas, you created, at channel loading become partially selected.

4. Paint over white color everything, except balls (fig. 3.89,). Invert the image in the channel command Invert to (Invert) submenu Adjust (Correction) of menu Image (Image). You created a channel negative (fig. 3.89,).

5. Load the channel as selection. The result of editing is available! Balls are selected, all remaining is masked (fig. 3.91).

6. It is sometimes convenient to create the channel not on the basis of selection, and from zero. For this purpose or select command New Channel (the New channel) from the menu of a palette and set parameters in window New Channel (the New channel), or simply click on the button of creation of the channel. The new channel name Light. Button usage has a lack — the program creates the channel with the conditional name and that it to call, all the same it is necessary to open a channel property sheet. However, if in the image there are not enough alpha channels, it is quite possible to manage and the conditional name.

7. Select tool Gradient (Gradient). Flood the new channel a gradient from black to the white. A gradient radial, its circuit and a gradient line are shown on fig. 3.92.

This new channel is useful to us in following section.

Saving in channels the necessary separation, you can fulfill with them arithmetical actions — to add, subtract, find intersection. For this purpose it is enough to load the first channel, and then to click on other channel, holding pushed the necessary key pattern (each combination there corresponds the type of the cursor):

Ctrl + Shift — for addition of channels

Ctrl + Alt — for subtraction of channels

Ctrl + Shift + Alt — for obtaining of intersection of channels

1. Load selection from channel Light. In the image there is very dim selection in the upper part.

2. Click on a line of channel Floor at pushed CTRL keys + Alt. The intersection, that is the general area of channels is found. It is the upper part of a background. Flood its dark green color.

3. Load selection from channel Ball. Click on a line of channel Floor at pushed CTRL keys + Shift. The total of channels is found. Now all background is selected, the figure and a basket with a grid is masked only.

4. Invert the received selection and save it as the channel.

Practically, the material considered in the previous section, is sufficient for high-grade usage of channels. Here we only is very short enumerate additional convergence on channels.

Control of channels can be produced from the menu. For selection saving in the channel command Save Selection (to Save selection), for loading — Load Selection (to Load selection) is provided. Both commands are in menu Select to (Select). Command Save Selection (to Save selection) opens a dialog box (fig. 3.93). (Document) it is possible to select any open document From uncovered list Document. This possibility allows to save selection as the channel not only in the current image, but also in any of open files or in the new document automatically created for the sake of such case. Is and. Restriction:

(Channel) it is possible to select saving from list Channel in the new channel (in this case it is necessary to enter his name in the field of input Name (the Name)), or in one of existing in the image selected from list Document (Document). If selection is saved in the existing channel, the type of interaction with its contents is selected: Replace Channel (to Replace the channel). Add to Channel (to Add to the channel), Subtract from Channel (to Subtract from the channel) and Intersect with Channel (to Find intersection with the channel). Click on button OK creates the new channel on the given parameters.

Window Load Selection (to Load selection) is very similar to the previous. As select the image from which it is necessary to load selection and a name of the channel for loading. If you want to load the channel from other document, its sizes should be identical to the active. Flag Invert to (Invert) inverts selection after loading. At loading of selection by means of window Load Selection (to Load selection) it is possible to produce addition, subtraction and intersection of loaded selection with already existing in the image, or to replace current selection loaded.

Arithmetical operations with channels are accessible in окнеB (Calculations). Operation in it is based on interaction of channels, an alpha and color, in the given modes of superimposing. Calculations can subject simultaneously some channels, defining the contribution of everyone. The given operations help to reach very unusual effects and are used for correction and exact separation. However, the amount of admirers of window Calculations (Calculation) is insignificant, as the method is deprived any visualization. If you are inclined to the analysis, try to research this area of the program independently.

At last we mark that after creation channels are saved together with the document in formats TIFF and PSD. The graphic file created by the program of adobe Photoshop, can include to 24 channels, it is enough this amount for any task. Additional channels increase file size (from calculation of 8 bits/piksel). For example, RGB-images increase at adding of each channel for 1/3 initial sizes. On the press alpha channels are not deduced.

Command Color Range (color Choice) unites in itself receptions of selection and operation with masks. On action it is similar enough on tool Magic Wand (Magic wand) in a mode of nonadjacent colors. The main differences two: at first, you see at once the received mask, and secondly, пикселы, not getting to the installed threshold, can be selected partially. Exists and still set of additional functions which are given by this useful command.

3. Click the mouse on the button of tool Eyedropper (Pipette) in dialog box Color Range (a color Choice). He allows to take a sample of color for creation of the selected area. All colors of the image will be compared to this sample and, depending on result of comparing, to join the selected area or to be eliminated from it.

4. Click tool Eyedropper (Pipette) around a front sail (fig. 3.94). It is possible to take a sample of color as from a miniature in view pane of dialog box Color Range (a color Choice), and in a document window.

5. The program builds a mask according to the given sample. The switch in the bottom of view pane is by default installed in position Selection (Selection), and it is possible to see the constructed mask directly in a dialog box. In position Image (Image) in the field of review is shown the source image (fig. 3.95).

6. The mask can be displayed and in a document window. Variants of review for a document window are selected from uncovered list Selection Preview (selection Review):

• None (is not present) — the source image.
• Grayscale (Half-tone) — a mask (the same that Selection (Selection) in dialog box view pane).
• Black Matte (the Black background) and White Matte (the White background) — the selected area on a black or white background accordingly.
• Quick Mask (the Fast mask) — a mask in a superimposing mode. Try to select each of variants.

7. Slider Fuzziness (Blur) fulfills the function similar to parameter Tolerance (Tolerance) for tool Magic Wand (Magic wand). Move it to the right until it will be selected as the sea and the sky (fig. 3.96) is possible the big area of a ship, but not.

8. After adding of colors you should eliminate superfluous shades as sky and sea sections got to the selected area also. We delete them from the selected area by means of tool Minus Eyedropper (the Pipette a minus), available in dialog box Color Range (a color Choice). Select this tool and click on those fragments of the image which should be removed from selection. The mask is corrected.

In

9. When the mask will include only the ship, close a dialog box click on the button APPRX. On the image there was a selected area (fig. 3.98,). Now the ship having very difficult form, is accurately selected against and it can be used separately. Save a mask in the channel casually not to lose result of operation.

10. Invert selection in the document Ship.jpg (fig. 3.98,) and flood the selected background a gradient at own discretion (fig. 3.98,).

• The bitmap image consists of points, instead of from objects. For instructions of boundary of object on such image it is necessary to create the selected area. Further with the received selected area it is possible to manipulate as with uniform object: to move it, to double, rotate or distort. The remaining (not selected) part of the image is protected from influence of any tools of editing Photoshop and is called as masked.
• The selected area forms by tools of square-topped and elliptic selection (if object (Magic wand) and commands Color Range (a color Choice) has the correct boundaries), manual оконтуриванием by means of group Lasso tools (Лассо), and also automatically, proceeding from a sign of proximity of color, by means of tool Magic Wand.
• Boundaries of the selected areas can be added and subtracted the friend from the friend, and also to change their sizes and to distort transformation commands that does not influence the image.
• If the image contains unnecessary fields, it can be кадрировано.
• Paint tools use general options are a paintbrush, a transparency (or pressing) and a superimposing mode. The paintbrush defines the form and a thickness of a dash of the drawing tool, pressing — an interaction level пикселов a dash with the image, a superimposing mode — a method of it взаимодейстия.
• It is possible to create new and to edit existing paintbrushes, and also to save created samples in a file.
• For filling of sections of the image with color command Fill (Filling) and fill tools Paint Bucket (Filling) and Gradient (Gradient) are used. Filling can be homogeneous, patten, graded-index. All types of filling are characterized by a mode of superimposing and a transparency.
• In the program there are sets of ready patterns for filling, but you can easily create new samples of patterns and save them.
• Samples of gradients also are stored in special sets which are accessible to change and addition. You can edit colors of gradients, add and delete color passages, regulate a transparency. There are five types of gradients — linear, conical, radial, square, mirror.
• Color passage in a gradient can happen between certain colors or between the casual. The first variant of an extension name a color ramp, the second — noise.
• As the image can contain some objects demanding editing, saving of separation (masks) for a reuse in alpha channels is possible. The mask saved in alpha channel, at any moment can be loaded in the form of the selected area.
• Alpha channels are treated Photoshop as halftone images and programs (paint tools, acoustical correction, filters and etc.) can be edited directly by all means.
• The shade of gray on a mask defines, in what level the given section of the image, if a mask will be selected. To load. As a rule, white color specifies on masked, black — in the selected section of the image, however you can and change a mask display mode. By means of paint tools and selection it is possible to create alpha channel "from zero", drawing it as a normal half-tone picture.
• For fast creation of the selected area mode Quick Mask (the Fast mask) is used. In this mode Photoshop creates the temporary channel of a mask. It is especially convenient that it is displayed over the image and it is possible to see simultaneously both a mask, and those sections of the image which it masks.
• If masks have the identical sizes, they can be exposed to mathematical handling: to be added, be subtracted, be multiplied and etc. It allows to create masks for group of objects of separate masks for each of them.