Photoshop about Channels

The application of the channel is very extensive, we can use the channel to establish the selection, the various operations of the constituency. The channel can also be regarded as an image composed of primary colors, so the filter can be used for the transformation of single color channel, color adjustment, copy and paste work. Combining channels with masks, can greatly simplify the same selection of repeated operations, the use of masks can be established in various forms of the selection to save, and then convenient to call, and with the channel, we can easily use the filter, to create a tool can not use the selection tool and path tools to produce a variety of effects images.

The concept of a channel

The concept of channel is very unique in Photoshop, it is not as easy as the layer, the mystery is much more than the layer. It is based on the color model on the basis of the derivation of a simplified operation tool. For example, an RGB three-color diagram has three default channels: Red (red), green, Blue (blue). But if it is a CMYK image, there are four default channels: Cyan (blue-green), magenta (mauve), yellow (yellow), Black (dark). As a result, each channel is actually a single channel of a basic color in an image. In other words, the channel is to use the color value of the image to modify the image, we can take the channel as a camera in the filter light. Let's look at how an image is under a different independent channel.

Artwork Blue Red Gre En

Cyan Magenta Yellow Black

Channels can be divided into two types: the first to store the image color data, it belongs to the built-in channel, that is, the channels we see above; the second can be used to solidify the selection and mask and perform the same editing work as the image to complete the blending with the image, create a new selection, and so on, such as the alpha channel that is said in the mask. For the basic use of the channel, I will not say more, the basic is the operation of the mask. Here, let's look at some of the special channel applications.

Spot color (Spot channel)

We know that the color mode of print is CMYK mode, and spot color is a series of special premixed inks, we use to replace or supplement the CMYK ink color. In order to better reflect the image effect, and to add spot color, you must take advantage of the spot color channel. Spot colors can be used locally or as a hue to apply to the entire image. But first we want to add spot channels, and to allow spot colors to apply to the entire image, you must first convert the image mode to Duotone (duotone) mode, and then make further changes in the Conversion Mode dialog box. Let's take a look at:

1 converts the image to grayscale mode.

2 Execute Image/mode/duotone, this time out of the Duotone Options dialog box.

3 Select the number of spot-color channels you want to use in the Type Drop-down list.

4 Click in the gray box next to the ink and edit the hue of the image.

5 Click within the color block next to the ink, click the Custom button from the subsequent Open Color Picker dialog box to select a spot color.

6 Click OK to return to the Duotone Options dialog box.

7 converts the image to a two-color mode, while applying spot colors.

We can create up to four spot colors. However, if you want to use spot colors locally in the image, you should add a spot channel for the image. The method is as follows:

1) to add spot color part of the image to establish a constituency.

2 The implementation of the new spot Channel in the Channel face board (newly spot color channel), the New Spot Channel dialog box option appears

3 in solidity (density) Zhong, enter the value between 0~100. Used to simulate the density of a print spot color on the screen. When the density is 100%, the simulation completely covers the bottom of the ink, the density is 0 o'clock, the simulation completely shows the bottom of the ink

3 in name is of course a name for this new monochrome channel. However, this name is very important, in order to facilitate spot color by those who read the files of other applications to identify, we can not arbitrarily take some strange names, preferably in Chinese, otherwise, the file can not read the correct print, do not blame me!

4 Finally, let's click Color in the ink characteristics (Ink feature) and select a color in the picker that appears. Here I choose the light blue. The density is set to 25.

5) and then click the OK button, the image added a spot color, while the channel work panel appears new channel Pantone xxx CVC, where xxx represents the color of the selected ink color code.

Final effect Diagram

The effect of a spot-color channel can be achieved by using other tools such as the selection tool. But in print it has a very

Important role that I will discuss in detail in color.

Split and merge Channels

When a color mode image file is too large, we can not copy it completely to the media (floppy disk, etc.) can be used to split the channel method, a picture into a number of grayscale, when necessary, and then merge them into a picture.

In addition, image splitting and merging can get different image effects. Let me give you an example:

1) Open the original image, and then perform windows/show channels

Original artwork (red as the main color)

Set blue as the primary color to set green as the primary color

2 Click on the channels panel in the small triangle, in the pop-up dialog box, select Split channels, a picture split into several grayscale, including alpha channel. The split file can be edited separately, and if you do not change the image mode, you can also merge to an RGB image.

3 Click on the channels panel in the Black Triangle, pop-up dialog box, select the merge channels.

4 in the left of the dialog box, we can choose a different stacking order, red can be seen as the main color, we put it in order as 1_g.bmp and 1_r.bmp, and then click OK, we saw the above two effects picture. As we can see, such a simple operation can change the overall style of a picture. Visible flexible and skilled application channel, can

With the color of the image to make many other tools do not have the effect.

Adjust image tones

Channel image editing mainly embodies in two aspects: one is to adjust the color channel image, so that the overall tone of the image changes, the other is to the channel image itself for the compilation process, the production of complex, using other tools can not make the selection and effect.

The principle of image color is not described here. Let's look at an example to see how powerful the channel is for color editing.

Original Tutu II

1) Open the original artwork.

2 select red (red) channel, perform filter/artistic/colored Pencil, then click OK directly. Get the second effect of graph. We see that the red in the image produces the special effects of the color pen.

Figure three Figure Four

3 then choose Green (green) channel, execute Filter/artistic/water Color, click OK directly. Get the results shown in Figure three. We see that the green image part of the image produces the effect of a watercolor marker.

4 finally select the Blue (blue) channel, execute the Filter/distort/shear, and pull the twisted line open, so that you can see more obvious effects, as shown in Figure four. In this way, an ordinary image becomes the effect of Tusi, imagine how to use other tools to do it?

We can create a selection and then make further image modifications to the established selection through the channel, and we can also use the channel to mix several selections and use the filter to get a good effect image.

Apply Image and Calculations commands

These two commands are mixed with the image for the alpha channel, and are then blended to create a few selections, often with fantastic images.

Let me see the application Image command first:

1 Open an image file, create a new alpha channel, click on the Channels Panel has a new icon below.

2 Click on the alpha channel, this time the image is dark, but this is a normal phenomenon. Then let's use the text Mask tool, write a few words on the image, and create a new selection.

3) filled with white

4) but hit the main color channel and switch to the normal image.

5 Execution image/apply image appears on the left side of the set area.

We change the channel from RGB to alpha 1 and then click Invert. Other inconvenience, at this time get the bottom right figure effect. When we cancel the invert, we get the bottom left image effect. As you can see, apply image fills the layer in the source with the image in channel or outside the channel selection.

No invert selected invert

We see a target at the bottom of the option box, where the blending (blending) refers to the blending method (which is a lot of content that will be mentioned in the description of the layer); Opacity (transparency) is, of course, the control of the transparency of the image. At the bottom there is a mask, right, this is a mask option, is to select the area you want to protect, three options and source exactly the same, there is a invert.

Then look at the calculations command:

The calculations command in image provides a number of features similar to the Apply Image command, such as the ability to choose a blending option and opacity to produce a blending effect. But there are also differences, mainly because calculations cannot produce effects in a composite channel.

Let's take an example of an image file with only a background layer and an alpha channel to see what functionality the calculations has.

1 Open an image file, such as Figure A

Figure I figure II

2 Alt-click the New button on the channels face board to establish channel Alpha 1 in the Mask range, or select Masked Areas in the pop-up dialog box.

3 Use text to create a selection, if you are dissatisfied with the size or position of the text, you can execute the edit/free transform command, then adjust, and finally fill with white, and cancel the selection.

4 make the foreground color and background color The default black and white, and then directly click on the New button in the channel face board to establish the channel Alpha 2 channel in the selection range.

5 Using the Rectangular selection tool, select the two rectangle and the text to intersect the rectangular marquee. As shown in Figure two.

6 Select Alpha 2 channel, execute filter/blur/radial Blur command, set amount value to 25,blur method to select spin, quality select Draft. Get the results as shown in Figure three.

Figure Three

7 then go back to the RGB image, perform select/all or press CTRL + A to select all the original images, and then execute the edit/cut command to cut the image onto the Clipboard. Then execute the image/calculations command and make Source 1 alpha 1,source 2 Alpha 2,result for selection, (Make the result a selection) and select blending (blending mode) to be a difference (difference) opacity value of 100.

8 Open the Mask panel, the channels selected as ALPHA1, and finally the result selected as selection.

9 execute edit/past into; Get the result as shown in Figure four.

Calculation Advanced Options

Figure Four