8.15. Compose
| 8. The “Colors” Menu |

### 8.15. Compose

#### 8.15.1. Overview

Figure 15.142. Example for the “Compose” command

Decomposed image (RGB decomposition)

“Compose” applied

This command constructs an image from several grayscale images or layers, for instance from extracted RGB, HSV... components. You can also build an image from grayscale images or layers created independently.

#### 8.15.2. Activate the command

- You can find this command in the image window menu under Colors → Components → Compose…. It is enabled if your image is grayscale.

#### 8.15.3. Options

Figure 15.143. “Compose” command options

Compose Channels

  You can select there the color space to be used: RGB, HSV... The options are described in the following Decompose command.

Channel Representation

  Allows you to select which channel will be affected to each image channel. You may use this option, for example, to exchange color channels:

  Figure 15.144. Channel Representation example: exchange two channels

  Original image

  Decomposed to layers

  Applied Channel Representation

  Composed image

  Mask Value: Instead of selecting a layer or an image to build the channel, you can give the channel a value from 0 to 255. But note that at least one channel must be formed from a layer or image.

| Tip
If Compose options are different from Decompose ones, for instance an image decomposed to RGB then re-composed to LAB, you will get interesting color effects. Test it!

8.14. Channel Mixer |  | 8.16. Decompose