Adobe Photoshop uses channels to store color information about an image. Geographic Imager Channel Management allows you to control channel mapping and assignment of channel color roles for false-composite multi-band imagery. Channel Management is available on the Geographic Imager panel and when using Advanced Import.
Click the Channel Management button on the Geographic Imager panel.
Channel Management button
The Color Mode drop-down list provides available color modes: RGB Color, Lab Color, Grayscale, and CMYK Color. Each color mode has its own set of channel colors:
Color Mode Channels
Red, Green, Blue
Lightness, A, B
Cyan, Magenta, Yellow, Black
To edit how the color mode channels are assigned, click the Channel Role drop-down list to assign that channel a new color (such as Red, Green, or Blue, for an RGB color mode). To change a channel name, double-click one in the Channel Name column and type a new name.
Important Channel Management Notes
Live Preview and Display One Channel Only options is not available in Adobe Photoshop 2021 and is not available on macOS. On Windows for Adobe Photoshop 2020 and older, if Live Preview is not functioning, go to Adobe Photoshop Preferences > Performance and ensure that Use Graphics Processor is enabled.
By default, if the color mode of an image can't be detected, the color mode is set to Grayscale Color with alpha channels if it has fewer than three channels. Otherwise Color Mode is set to RGB Color with alpha channels.
Channel management is not compatible with 32-bit images.
Color Mode is not available for images imported from a Web Map Service.
Channel name read and write capability is only supported with the IMG format.
Changing color modes will flatten layers and any transparencies will be lost.
When using Advanced Import, the MrSID encoder (MG4) adds an extra alpha channel as transparency when it saves an image. This means that one channel is used as transparency and the total number of alpha channels is less than is shown in the channel management dialog box.
You can only apply transparency from a channel using Advanced Import.