Channel basics

  1. Photoshop User Guide
  2. Introduction to Photoshop
    1. Dream it. Make it.
    2. What's new in Photoshop
    3. Edit your first photo
    4. Create documents
    5. Photoshop | Common Questions
    6. Photoshop system requirements
    7. Migrate presets, actions, and settings
    8. Get to know Photoshop
  3. Photoshop and Adobe services
    1. Photoshop and Adobe Stock
    2. Creative Cloud Libraries
    3. Creative Cloud Libraries in Photoshop
    4. Grid and guides
    5. Creating actions
    6. Undo and history
    7. Default keyboard shortcuts
    8. Touch capabilities and customizable workspaces
    9. Use the Touch Bar with Photoshop
    10. Use the Capture in-app extension in Photoshop
  4. Photoshop on the iPad
    1. Photoshop on the iPad | Common questions
    2. Get to know the workspace
    3. System requirements | Photoshop on the iPad
    4. Create, open, and export cloud documents
    5. Add photos
    6. Work with layers
    7. Draw and paint with brushes
    8. Make selections and add masks
    9. Retouch your composites
    10. Work with adjustment layers
    11. Adjust the tonality of your composite with Curves
    12. Apply transform operations
    13. Crop and rotate your composites
    14. Rotate, pan, zoom, and reset canvas
    15. Work with Type layers
    16. Work with Photoshop and Lightroom
    17. Get missing fonts in Photoshop on the iPad
    18. Japanese Text in Photoshop on the iPad
    19. Manage app settings
    20. Touch shortcuts and gestures
    21. Keyboard shortcuts
    22. System requirements 1.x | Photoshop on the iPad
    23. System requirements 2.x | Photoshop on the iPad
    24. Edit your image size
    25. Livestream as you create in Photoshop on the iPad
    26. Correct imperfections with the Healing Brush
    27. Create brushes in Capture and use them in Photoshop
  5. Cloud documents
    1. Photoshop cloud documents | Common questions
    2. Photoshop cloud documents | Workflow questions
    3. Manage and work with cloud documents in Photoshop
    4. Upgrade cloud storage for Photoshop
    5. Unable to create or save a cloud document
    6. Solve Photoshop cloud document errors
    7. Collect cloud doc sync logs
    8. Share access and edit your cloud documents
  6. Workspace
    1. Workspace basics
    2. Create documents
    3. Use the Touch Bar with Photoshop
    4. Microsoft Dial support in Photoshop
    5. Tool galleries
    6. Performance preferences
    7. Use tools
    8. Touch gestures
    9. Touch capabilities and customizable workspaces
    10. Technology previews
    11. Metadata and notes
    12. Quickly share your creations
    13. Place Photoshop images in other applications
    14. Preferences
    15. Default keyboard shortcuts
    16. Rulers
    17. Show or hide non-printing Extras
    18. Specify columns for an image
    19. Undo and history
    20. Panels and menus
    21. Place files
    22. Position elements with snapping
    23. Position with the Ruler tool
    24. Presets
    25. Customize keyboard shortcuts
    26. Grid and guides
  7. Web, screen, and app design
    1. Photoshop for design
    2. Artboards
    3. Export files in Photoshop
    4. Device Preview
    5. Copy CSS from layers
    6. Slice web pages
    7. HTML options for slices
    8. Modify slice layout
    9. Work with web graphics
    10. Create web photo galleries
  8. Image and color basics
    1. How to resize images
    2. Work with raster and vector images
    3. Image size and resolution
    4. Acquire images from cameras and scanners
    5. Create, open, and import images
    6. View images
    7. Invalid JPEG Marker error | Opening images
    8. Viewing multiple images
    9. Customize color pickers and swatches
    10. High dynamic range images
    11. Match colors in your image
    12. Convert between color modes
    13. Color modes
    14. Erase parts of an image
    15. Blending modes
    16. Choose colors
    17. Customize indexed color tables
    18. Image information
    19. Distort filters are unavailable
    20. About color
    21. Color and monochrome adjustments using channels
    22. Choose colors in the Color and Swatches panels
    23. Sample
    24. Color mode or Image mode
    25. Color cast
    26. Add a conditional mode change to an action
    27. Add swatches from HTML CSS and SVG
    28. Bit depth and preferences
  9. Layers
    1. Layer basics
    2. Nondestructive editing
    3. Create and manage layers and groups
    4. Select, group, and link layers
    5. Place images into frames
    6. Layer opacity and blending
    7. Mask layers
    8. Apply Smart Filters
    9. Layer comps
    10. Move, stack, and lock layers
    11. Mask layers with vector masks
    12. Manage layers and groups
    13. Layer effects and styles
    14. Edit layer masks
    15. Extract assets
    16. Reveal layers with clipping masks
    17. Generate image assets from layers
    18. Work with Smart Objects
    19. Blending modes
    20. Combine multiple images into a group portrait
    21. Combine images with Auto-Blend Layers
    22. Align and distribute layers
    23. Copy CSS from layers
    24. Load selections from a layer or layer mask's boundaries
    25. Knockout to reveal content from other layers
    26. Layer
    27. Flattening
    28. Composite
    29. Background
  10. Selections
    1. Select and Mask workspace
    2. Make quick selections
    3. Get started with selections
    4. Select with the marquee tools
    5. Select with the lasso tools
    6. Select a color range in an image
    7. Adjust pixel selections
    8. Convert between paths and selection borders
    9. Channel basics
    10. Move, copy, and delete selected pixels
    11. Create a temporary quick mask
    12. Save selections and alpha channel masks
    13. Select the image areas in focus
    14. Duplicate, split, and merge channels
    15. Channel calculations
    16. Selection
    17. Bounding box
  11. Image adjustments
    1. Perspective warp
    2. Reduce camera shake blurring
    3. Healing brush examples
    4. Export color lookup tables
    5. Adjust image sharpness and blur
    6. Understand color adjustments
    7. Apply a Brightness/Contrast adjustment
    8. Adjust shadow and highlight detail
    9. Levels adjustment
    10. Adjust hue and saturation
    11. Adjust vibrance
    12. Adjust color saturation in image areas
    13. Make quick tonal adjustments
    14. Apply special color effects to images
    15. Enhance your image with color balance adjustments
    16. High dynamic range images
    17. View histograms and pixel values
    18. Match colors in your image
    19. How to crop and straighten photos
    20. Convert a color image to black and white
    21. Adjustment and fill layers
    22. Curves adjustment
    23. Blending modes
    24. Target images for press
    25. Adjust color and tone with Levels and Curves eyedroppers
    26. Adjust HDR exposure and toning
    27. Filter
    28. Blur
    29. Dodge or burn image areas
    30. Make selective color adjustments
    31. Replace object colors
  12. Adobe Camera Raw
    1. Camera Raw system requirements
    2. What's new in Camera Raw
    3. Introduction to Camera Raw
    4. Create panoramas
    5. Supported lenses
    6. Vignette, grain, and dehaze effects in Camera Raw
    7. Default keyboard shortcuts
    8. Automatic perspective correction in Camera Raw
    9. How to make non-destructive edits in Camera Raw
    10. Radial Filter in Camera Raw
    11. Manage Camera Raw settings
    12. Open, process, and save images in Camera Raw
    13. Repair images with the Enhanced Spot Removal tool in Camera Raw
    14. Rotate, crop, and adjust images
    15. Adjust color rendering in Camera Raw
    16. Feature summary | Adobe Camera Raw | 2018 releases
    17. New features summary
    18. Process versions in Camera Raw
    19. Make local adjustments in Camera Raw
  13. Image repair and restoration
    1. Remove objects from your photos with Content-Aware Fill
    2. Content-Aware Patch and Move
    3. Retouch and repair photos
    4. Correct image distortion and noise
    5. Basic troubleshooting steps to fix most issues
  14. Image transformations
    1. Transform objects
    2. Adjust crop, rotation, and canvas size
    3. How to crop and straighten photos
    4. Create and edit panoramic images
    5. Warp images, shapes, and paths
    6. Vanishing Point
    7. Use the Liquify filter
    8. Content-aware scaling
    9. Transform images, shapes, and paths
    10. Warp
    11. Transform
    12. Panorama
  15. Drawing and painting
    1. Paint symmetrical patterns
    2. Draw rectangles and modify stroke options
    3. About drawing
    4. Draw and edit shapes
    5. Painting tools
    6. Create and modify brushes
    7. Blending modes
    8. Add color to paths
    9. Edit paths
    10. Paint with the Mixer Brush
    11. Brush presets
    12. Gradients
    13. Fill and stroke selections, layers, and paths
    14. Draw with the Pen tools
    15. Create patterns
    16. Generate a pattern using the Pattern Maker
    17. Manage paths
    18. Manage pattern libraries and presets
    19. Draw or paint with a graphics tablet
    20. Create textured brushes
    21. Add dynamic elements to brushes
    22. Gradient
    23. Paint stylized strokes with the Art History Brush
    24. Paint with a pattern
    25. Sync presets on multiple devices
  16. Text
    1. Work with OpenType SVG fonts
    2. Format characters
    3. Format paragraphs
    4. How to create type effects
    5. Edit text
    6. Line and character spacing
    7. Arabic and Hebrew type
    8. Fonts
    9. Troubleshoot fonts
    10. Asian type
    11. Create type
    12. Text Engine error using Type tool in Photoshop | Windows 8
    13. World-Ready composer for Asian Scripts
    14. How to add and edit text in Photoshop
  17. Video and animation
    1. Video editing in Photoshop
    2. Edit video and animation layers
    3. Video and animation overview
    4. Preview video and animations
    5. Paint frames in video layers
    6. Import video files and image sequences
    7. Create frame animations
    8. Creative Cloud 3D Animation (Preview)
    9. Create timeline animations
    10. Create images for video
  18. Filters and effects
    1. Use the Liquify filter
    2. Use the Blur Gallery
    3. Filter basics
    4. Filter effects reference
    5. Add Lighting Effects
    6. Use the Adaptive Wide Angle filter
    7. Use the Oil Paint filter
    8. Layer effects and styles
    9. Apply specific filters
    10. Smudge image areas
  19. Saving and exporting
    1. Save files in graphics formats
    2. Save your files in Photoshop
    3. File formats
    4. Save and export video and animations
    5. Save PDF files
    6. Digimarc copyright protection
  20. Printing
    1. Print 3D objects
    2. Print from Photoshop
    3. Print with color management
    4. Contact Sheets and PDF Presentations
    5. Print photos in a picture package layout
    6. Print spot colors
    7. Duotones
    8. Print images to a commercial printing press
    9. Improve color prints from Photoshop
    10. Troubleshoot printing problems | Photoshop
  21. Automation
    1. Creating actions
    2. Create data-driven graphics
    3. Scripting
    4. Process a batch of files
    5. Play and manage actions
    6. Add conditional actions
    7. About actions and the Actions panel
    8. Record tools in actions
    9. Add a conditional mode change to an action
    10. Photoshop UI toolkit for plug-ins and scripts
  22. 3D and technical imaging
    1. Creative Cloud 3D Animation (Preview)
    2. Print 3D objects
    3. 3D painting
    4. 3D panel enhancements | Photoshop
    5. Essential 3D concepts and tools
    6. 3D rendering and saving
    7. Create 3D objects and animations
    8. Image stacks
    9. 3D workflow
    10. Measurement
    11. DICOM files
    12. Photoshop and MATLAB
    13. Count objects in an image
    14. Combine and convert 3D objects
    15. 3D texture editing
    16. Adjust HDR exposure and toning
    17. 3D panel settings
  23. Color Management
    1. Understanding color management
    2. Keeping colors consistent
    3. Color settings
    4. Work with color profiles
    5. Color-managing documents for online viewing
    6. Color-managing documents when printing
    7. Color-managing imported images
    8. Proofing colors

About channels

Channels are grayscale images that store different types of information:

  • Color information channels are created automatically when you open a new image. The image’s color mode determines the number of color channels created. For example, an RGB image has a channel for each color (red, green, and blue) plus a composite channel used for editing the image.

  • Alpha channels store selections as grayscale images. You can add alpha channels to create and store masks, which let you manipulate or protect parts of an image. (See About masks and alpha channels.)

  • Spot color channels specify additional plates for printing with spot color inks. (See About spot colors.)

    An image can have up to 56 channels. All new channels have the same dimensions and number of pixels as the original image.

    The file size required for a channel depends on the pixel information in the channel. Certain file formats, including TIFF and Photoshop formats, compress channel information and can save space. The size of an uncompressed file, including alpha channels and layers, appears as the right-most value in the status bar at the bottom of the window when you choose Document Sizes from the pop‑up menu.

 

Note:

As long as you save a file in a format supporting the image’s color mode, the color channels are preserved. Alpha channels are preserved only when you save a file in Photoshop, PDF, TIFF, PSB, or raw formats. DCS 2.0 format preserves only spot channels. Saving in other formats may cause channel information to be discarded.

Channels panel overview

The Channels panel lists all channels in the image—composite channel first (for RGB, CMYK, and Lab images). A thumbnail of the channel’s contents appears to the left of the channel name; the thumbnail is automatically updated as you edit the channel.

Photoshop Channel types
Channel types

A. Color channels B. Spot channels C. Alpha channels 

Display the Channels panel

  1. Choose Windows > Channels.

Resize or hide channel thumbnails

  1. Choose Panel Options from the Channels panel menu. Click a thumbnail size or click None to turn off the display of thumbnails.

    Viewing thumbnails is a convenient way of tracking channel contents; however, turning off the display of thumbnails can improve performance.

Show or hide a channel

You can use the Channels panel to view any combination of channels in the document window. For example, you can view an alpha channel and the composite channel together to see how changes made in the alpha channel relate to the entire image.

  1. Click in the eye column next to the channel to show or hide that channel. (Click the composite channel to view all default color channels. The composite channel is displayed whenever all the color channels are visible.)
    Note:

    To show or hide multiple channels, drag through the eye column in the Channels panel.

Show color channels in color

Individual channels are displayed in grayscale. In RGB, CMYK, or Lab images, you can view the individual channels in color. (In Lab images, only the a and b channels appear in color.) If more than one channel is active, the channels always appear in color.

You can change the default to show the individual color channels in color. When a channel is visible in the image, an eye icon  appears to its left in the panel.

  1. Do one of the following:
    • In Windows, choose Edit > Preferences > Interface.

    • In Mac OS, choose Photoshop > Preferences > Interface.

  2. Select Show Channels In Color, and click OK.

Select and edit channels

You can select one or more channels in the Channels panel. The names of all selected, or active, channels are highlighted.

Photoshop Select multiple channels
Selecting multiple channels

A. Not visible or editable B. Visible but not selected for editing C. Selected for viewing and editing D. Selected for editing but not viewing 

  • To select a channel, click the channel name. Shift-click to select (or deselect) multiple channels.
  • To edit a channel, select it and then use a painting or editing tool to paint in the image. You can paint on only one channel at a time. Paint with white to add the selected channel’s color at 100% intensity. Paint with a value of gray to add the channel’s color at a lower intensity. Paint with black to fully remove the channel’s color.

Rearrange and rename alpha and spot channels

You can move alpha or spot channels above the default color channels only if the image is in Multichannel mode (Image > Mode > Multichannel). For information about that mode’s limitations, see Multichannel mode.

  • To change the order of alpha or spot channels, drag the channel up or down in the Channels panel. When a line appears in the position you want, release the mouse button.
Note:

Spot colors are overprinted in the order of their appearance from top to bottom in the Channels panel.

  • To rename an alpha or spot channel, double-click the channel’s name in the Channels panel, and enter a new name.

For more information, see Create a new spot channel.

Delete a channel

You may want to delete spot or alpha channels you no longer need before saving an image. Complex alpha channels can substantially increase the disk space required for an image.

  1. In Photoshop, select the channel in the Channels panel and do one of the following:
    • Alt-click (Windows) or Option-click (Mac OS) the Delete icon .

    • Drag the channel name in the panel to the Delete icon.

    • Choose Delete Channel from the Channels panel menu.

    • Click the Delete icon at the bottom of the panel, and then click Yes.

    Note:

    When you delete a color channel from a file with layers, visible layers are flattened and hidden layers are discarded. This is done because removing a color channel converts the image to Multichannel mode, which does not support layers. An image isn’t flattened when you delete an alpha channel, a spot channel, or a quick mask.

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