As with layers, channels have their own palette that acts as command central for viewing, creating, and managing tasks. The first step is accessing channels by choosing Window-->Channels.
Viewing channels without a remote
To select a channel, click the channel thumbnail or name in the palette. To select more than one channel, Shift+click. To show or hide a channel, click in the eye column in the far left of the palette. Selecting a channel automatically makes it show. You can also drag through the column to hide or show the channels quickly. CMYK, RGB, and Lab images have a composite channel in addition to their individual channels. This composite channel is the combination of all the channels in the image and is named after the color mode.
Changing the default channel view
The default setting is to view your channels in grayscale. You can, however, view them in color. To do so, choose Edit-->Preferences-->Display & Cursors (Photoshop-->Preferences-->Display & Cursors on Mac OS X) and select Color Channels in Color. Although this option graphically exemplifies the way an image comprises separate color channels, it really does you no good if you want to work with your channels for editing. That’s because the color view obscures details and makes measuring the impact of adjustments and filters more difficult. You need to see the channels in their true grayscale form for that.
To change the size of the thumbnail that appears, choose Palette Options from the Channels palette pop-up menu. Select your desired thumbnail size. If you’re working with several channels and you have a dinosaur of a computer, you can also choose None to turn off the thumbnails — to improve its performance.
Duplicating and deleting channels
Duplicating channels is something you may do quite often. I know I do. And of course, deleting channels isn’t something you do only if you’re a neat freak. Channels take up a lot of memory, so it’s always good to get rid of the ones you no longer need. Here are some instances when duplicating channels is a good idea:
- When you want to create a channel mask: First, you find a suitable channel and then make a duplicate. You can use channel masks to select difficult elements involving fine details, such as hair, fur, smoke, and so on.
- When you want to make a backup copy of the channel before doing some editing: It’s always a good idea to have a backup just to be on the safe side. For example, you may want to apply an Unsharp Mask filter to one or two channels to improve the focus of the image.
- To insert a copy of an alpha channel into another image: For example, maybe you spent an hour creating elaborate alpha channels for shadows and highlights on a product photographed in flat lighting. You may have 12 products, all the same shape, but different colors that you need to apply those highlights and shadows to. Rather than re-creating the wheel each time, you could simply duplicate the alpha channels into each file.
Duplicating channels
To duplicate a channel, follow these short steps:
1. Select your desired channel in the Channels palette.
2. Choose Duplicate Channel from the palette pop-up menu.
3. In the Duplicate section, name the channel.
You can also drag the channel to the New Channel icon at the bottom of the palette. If you do this, Photoshop provides a default name and bypasses Steps 4, 5, and 6.
4. In the Destination section, select a file from the Document drop-down list. Or choose New to create a new image.
You can choose your current image or any open image with the same pixel dimensions (size and resolution) as your current image. If you choose New, Photoshop creates a new image that has a single channel. Provide a name for the file.
5. Select Invert if you want to reverse the selected and unselected areas of the duplicate channel.
You use the Invert option primarily when you duplicate an existing alpha channel.
6. Click OK.
The dialog box closes. Your duplicate channel appears in the Channels palette.
Replacing one channel over another
To replace one channel over another, you can use the copy-and-paste method. In your current image, select your desired channel. Choose Select-->All and then Edit-->Copy. Select the channel in the destination image that you want to replace and choose Edit-->Paste. The pasted channel replaces the original one.
Deleting unwanted channels
To delete an unwanted channel — something you definitely want to do because channels can eat up a lot of space — select the channel in the Channels palette and do one of the following:
- Drag the channel to the trash can icon at the bottom of the palette.
- Choose Delete Channel from the palette pop-up menu.
- Click the trash can icon and then click Yes.
- Alt+click (Option+click on the Mac) on the trash can icon.
Rearranging and renaming channels
Although you can’t shuffle or rename color channels, you can do so with spot and alpha channels. To move a spot or alpha channel, simply drag it up or down in the Channels palette. When you see a dark line appear where you want the channel to go, release your mouse button. You can move a spot or alpha channel above a color channel only in a multichannel image. In short, in a multichannel image, each channel becomes an independent spot channel, and the channels no longer have a relationship with each other. Multichannel images also do not support layers. The only file formats that support this mode are Photoshop, Photoshop Raw, and Photoshop DCS 2.0 (DCS stands for Desktop Color Separations). To rename a spot or alpha channel, double-click the name in the Channel palette and type a new name. You can also choose Channel Options from the palette pop-up menu.
Splitting channels
You can split the channels of your image into separate images in separate files. Choose Split Channels from the palette pop-up menu. When you do so, your original image closes. The channel files have the name of your original image plus the channel name. You can split channels only on a flattened image — in other words, an image with no individual layers. You might want to split channels if you need to save your original file in a format that doesn’t preserve channels — such as EPS, which doesn’t support alpha channels — or you may want to split channels to merge them later on. Make sure that you save all changes in your original image before you split it because Photoshop closes it.
The Quick and Dirty Method for Duplicating Channels
You can also duplicate a channel to another image by dragging the channel. Open your destination image and drag the desired channel from your current image into the destination
image window. The duplicated channel appears in the Channels palette.
Merging channels
You can merge channels into a single image. The channels must be open, in grayscale mode, and have the same pixel dimensions. You can merge channels only when they are flattened images and have no layers. You may find a need to merge channels because you have a DCS (Desktop Color Separation) file that has lost its link (the original image) and it’s unusable. You can open the individual channel files and merge them into a single image. Then resave it as a DCS EPS. You can also merge color channels to create some unique special effects. For example, by mismatching your channels when you merge them, you can create some really bizarre, and sometimes beautiful, color shifts.
To merge channels, follow these steps:
1. Open your channel files and activate any one of them.
2. Choose Merge Channels from the palette pop-up menu.
3. Choose your desired color mode.
Any modes that are unavailable are grayed out. That’s because you may not have enough channels for that mode.
4. Enter the number of channels you want.
When you choose your mode in Step 3, Photoshop automatically fills in the number of channels for the mode. If you deviate and enter something different, the file becomes a multichannel file.
5. Click OK.
6. Select your channels.
If you want to merge the channels normally, make sure that each channel matches (Red for Red and so on). If you want to rearrange the channels, you can mix them.
7. If you are merging into a multichannel image, click Next. Repeat for each channel.
8. Click OK.
You have now merged your files into a single image, which appears in your Photoshop window. Photoshop closes individual channel files and merges any spot channels as alpha channels. If you have an image with alpha or spot channels, choose Multichannel from the Mode drop-down list in Step 3 or Photoshop will not include those channels in the merged image. After you merge the image, Photoshop gives all the channels the names Alpha 1, Alpha 2, Alpha 3, and so on. To get back to a color composite, choose Image-->Mode-->RGB Color or CMYK Color.
Viewing channels without a remote
To select a channel, click the channel thumbnail or name in the palette. To select more than one channel, Shift+click. To show or hide a channel, click in the eye column in the far left of the palette. Selecting a channel automatically makes it show. You can also drag through the column to hide or show the channels quickly. CMYK, RGB, and Lab images have a composite channel in addition to their individual channels. This composite channel is the combination of all the channels in the image and is named after the color mode.
Changing the default channel view
The default setting is to view your channels in grayscale. You can, however, view them in color. To do so, choose Edit-->Preferences-->Display & Cursors (Photoshop-->Preferences-->Display & Cursors on Mac OS X) and select Color Channels in Color. Although this option graphically exemplifies the way an image comprises separate color channels, it really does you no good if you want to work with your channels for editing. That’s because the color view obscures details and makes measuring the impact of adjustments and filters more difficult. You need to see the channels in their true grayscale form for that.
To change the size of the thumbnail that appears, choose Palette Options from the Channels palette pop-up menu. Select your desired thumbnail size. If you’re working with several channels and you have a dinosaur of a computer, you can also choose None to turn off the thumbnails — to improve its performance.
Duplicating and deleting channels
Duplicating channels is something you may do quite often. I know I do. And of course, deleting channels isn’t something you do only if you’re a neat freak. Channels take up a lot of memory, so it’s always good to get rid of the ones you no longer need. Here are some instances when duplicating channels is a good idea:
- When you want to create a channel mask: First, you find a suitable channel and then make a duplicate. You can use channel masks to select difficult elements involving fine details, such as hair, fur, smoke, and so on.
- When you want to make a backup copy of the channel before doing some editing: It’s always a good idea to have a backup just to be on the safe side. For example, you may want to apply an Unsharp Mask filter to one or two channels to improve the focus of the image.
- To insert a copy of an alpha channel into another image: For example, maybe you spent an hour creating elaborate alpha channels for shadows and highlights on a product photographed in flat lighting. You may have 12 products, all the same shape, but different colors that you need to apply those highlights and shadows to. Rather than re-creating the wheel each time, you could simply duplicate the alpha channels into each file.
Duplicating channels
To duplicate a channel, follow these short steps:
1. Select your desired channel in the Channels palette.
2. Choose Duplicate Channel from the palette pop-up menu.
3. In the Duplicate section, name the channel.
You can also drag the channel to the New Channel icon at the bottom of the palette. If you do this, Photoshop provides a default name and bypasses Steps 4, 5, and 6.
4. In the Destination section, select a file from the Document drop-down list. Or choose New to create a new image.
You can choose your current image or any open image with the same pixel dimensions (size and resolution) as your current image. If you choose New, Photoshop creates a new image that has a single channel. Provide a name for the file.
5. Select Invert if you want to reverse the selected and unselected areas of the duplicate channel.
You use the Invert option primarily when you duplicate an existing alpha channel.
6. Click OK.
The dialog box closes. Your duplicate channel appears in the Channels palette.
Replacing one channel over another
To replace one channel over another, you can use the copy-and-paste method. In your current image, select your desired channel. Choose Select-->All and then Edit-->Copy. Select the channel in the destination image that you want to replace and choose Edit-->Paste. The pasted channel replaces the original one.
Deleting unwanted channels
To delete an unwanted channel — something you definitely want to do because channels can eat up a lot of space — select the channel in the Channels palette and do one of the following:
- Drag the channel to the trash can icon at the bottom of the palette.
- Choose Delete Channel from the palette pop-up menu.
- Click the trash can icon and then click Yes.
- Alt+click (Option+click on the Mac) on the trash can icon.
Rearranging and renaming channels
Although you can’t shuffle or rename color channels, you can do so with spot and alpha channels. To move a spot or alpha channel, simply drag it up or down in the Channels palette. When you see a dark line appear where you want the channel to go, release your mouse button. You can move a spot or alpha channel above a color channel only in a multichannel image. In short, in a multichannel image, each channel becomes an independent spot channel, and the channels no longer have a relationship with each other. Multichannel images also do not support layers. The only file formats that support this mode are Photoshop, Photoshop Raw, and Photoshop DCS 2.0 (DCS stands for Desktop Color Separations). To rename a spot or alpha channel, double-click the name in the Channel palette and type a new name. You can also choose Channel Options from the palette pop-up menu.
Splitting channels
You can split the channels of your image into separate images in separate files. Choose Split Channels from the palette pop-up menu. When you do so, your original image closes. The channel files have the name of your original image plus the channel name. You can split channels only on a flattened image — in other words, an image with no individual layers. You might want to split channels if you need to save your original file in a format that doesn’t preserve channels — such as EPS, which doesn’t support alpha channels — or you may want to split channels to merge them later on. Make sure that you save all changes in your original image before you split it because Photoshop closes it.
The Quick and Dirty Method for Duplicating Channels
You can also duplicate a channel to another image by dragging the channel. Open your destination image and drag the desired channel from your current image into the destination
image window. The duplicated channel appears in the Channels palette.
Merging channels
You can merge channels into a single image. The channels must be open, in grayscale mode, and have the same pixel dimensions. You can merge channels only when they are flattened images and have no layers. You may find a need to merge channels because you have a DCS (Desktop Color Separation) file that has lost its link (the original image) and it’s unusable. You can open the individual channel files and merge them into a single image. Then resave it as a DCS EPS. You can also merge color channels to create some unique special effects. For example, by mismatching your channels when you merge them, you can create some really bizarre, and sometimes beautiful, color shifts.
To merge channels, follow these steps:
1. Open your channel files and activate any one of them.
2. Choose Merge Channels from the palette pop-up menu.
3. Choose your desired color mode.
Any modes that are unavailable are grayed out. That’s because you may not have enough channels for that mode.
4. Enter the number of channels you want.
When you choose your mode in Step 3, Photoshop automatically fills in the number of channels for the mode. If you deviate and enter something different, the file becomes a multichannel file.
5. Click OK.
6. Select your channels.
If you want to merge the channels normally, make sure that each channel matches (Red for Red and so on). If you want to rearrange the channels, you can mix them.
7. If you are merging into a multichannel image, click Next. Repeat for each channel.
8. Click OK.
You have now merged your files into a single image, which appears in your Photoshop window. Photoshop closes individual channel files and merges any spot channels as alpha channels. If you have an image with alpha or spot channels, choose Multichannel from the Mode drop-down list in Step 3 or Photoshop will not include those channels in the merged image. After you merge the image, Photoshop gives all the channels the names Alpha 1, Alpha 2, Alpha 3, and so on. To get back to a color composite, choose Image-->Mode-->RGB Color or CMYK Color.
Working with Photoshop Channels
![Working with Photoshop Channels]()
Reviewed by Pepen2710
on
1:56:00 AM
Rating:
No comments:
Post a Comment