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How to create an alpha channel

Making your background transparent in SketchBookThe Background layer is at the bottom of the Layer Editor. When hidden (tap Hiding a layer group icon to hide it), this creates an alpha channel.

It’s handy when compositing (combining) an assortment of images. The alpha channel will enable the background of one image to show through the alpha channel of the other images. This is because it doesn’t contain any pixels. SketchBook will display a grey and white checked pattern to indicate an alpha channel.

Creating an alpha channel in SketchBook for Desktop

Example of an alpha channel in SketchBook

Before saving a file, you can turn off the background layer to have a transparent background (alpha channel).

  1. In the Layer Editor, in the Background layer, tap Create alpha to turn off the background layer and create an alpha channel.Making your background transparent in SketchBook
  2. Select File > Save. When saving an image with an alpha channel, select TIFF, PNG, or PSD.

Creating an alpha channel in SketchBook for Mobile

The Background layer is at the bottom of the Layer Editor. When hidden (tap Hiding a layer group icon to hide it), this creates an alpha channel.

1. Do one of the following, depending on the device and version of SketchBook you’re using:

  • If you’re on a tablet, the Layer Editor is visible by default, along the right of your screen.

    If you want to work without it displayed, tap Hide UI tool. Tap this to enter Dual Mode in the Autodesk SketchBook for mobile version to hide the UI. Tap it again to display the UI.

  • If you’re on a tablet and the UI is hidden, quickly access the Layer Editor using the trigger. With one hand, tap Trigger icon in the Autodesk SketchBook iOS version and drag down to select and hold Layer from the menu that appears. This will open the Layer Editor, which appears along the right of your screen. While you continue with Layer selected, use your other hand to make changes in the Layer Editor. When you release the Layer menu option with your other hand, the UI will disappear again.
  • If you’re on a handheld device using SketchBook v.4.0 or above, such as a phone, tap Layer icon in SketchBook for Mobile to open the Layer Editor.
  • If you’re on a handheld device using SketchBook v.3.7.4 or below, such as a phone, tap  to open the Layer Editor.

2. Within the Layer Editor, find the Background layer. Tap Hiding a layer group icon to hide the Background layer. A grey and white checked pattern will appear in the background. This is the alpha channel.

This creates an alpha channel in SketchBook for Mobile

If a checkered pattern doesn’t appear in the background, that indicates that the background of one of your layers is filled with pixels. Turn off each layer until you find the troublesome layer. Use Magic Wand selection to remove the pixels.

3. Tap Info Settings icon in the mobile version of SketchBook, select Gallery icon in the mobile version of SketchBook Gallery, then Save current sketch.

4. Tap Export icon, select Export PSD, then the method for export, such as Mail, iCloud Photo Sharing, etc.

Creating an alpha channel in SketchBook for Windows 10 (Pro)

Not available to Free users

When saving a file, you can saving with an alpha channel and set the format of the saved file.

Transparent Background with layers in SketchBook

  1. If the Layer Editor isn’t open, in the toolbar along the top, tap Layer Basics - UI Toggle and select Layer Editor.
  2. In the Background layer, tap Show/Hide Background icon to hide the background layer. This creates an alpha channel and make the background of a layer transparent.
  3. Select File > Save. When saving an image with an alpha channel, select TIFF.

 

Updated on March 7, 2018

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