Creating an alpha channel

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Making your background transparent in Sketchbook

The Background layer is at the bottom of the Layer Editor. When hidden (tap 1665122998684-layer_hide@2x.png 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 Pro for desktop

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.
  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 devices

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 in the Sketchbook 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 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, such as a phone, tap Layer icon in Sketchbook mobile 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. In the Gallery, tap Export icon, select Export PSD, then the method for export, such as Mail, etc.


Delete

Warning

The iOS Photos app is known to convert PNG files to JPG, with the most obvious result being the loss of a transparent background. It is more common for files over 4k and under 360px, but it can happen to any file. The only workaround if this is happening on your device is to save your PNGs to Files instead of to Photos.