Render Layer Output

The example shows the Still Image rendering of two interlocking rings.
The outer (blue) and inner (white) rings were put on two separate Render Layers.

• Straight Alpha – Unmatted – (Default) This alpha mode extends the color at the edges of Render Layers to the semitransparent pixels of anti-aliased edges. This avoids any black fringing when compositing the Render Layers in post-processing. This alpha type is the default, as it provides the best results in most situations.
• Premultiplied Alpha – Matted with Black – This alpha mode premultiplies the Render Layer image by blending or matting any semi-transparent pixels, due to anti-aliasing, with black. This can cause black fringing when compositing the Render Layers, if the image editing application does not support specifying the black matting color and adjusting for it. In Photoshop, the issue can be remedied by trying one of the matting options, found under Image > Matting.
• Aliased – Opaque Fringe – This alpha mode extends the color at the edges of Render Layers and creates fully opaque (aliased) edges. This avoids any transparent gaps between adjoining Render Layers when compositing the Render Layers in post-processing. Due to the negative visual consequences of aliased edges, this mode should only be used if gaps between Render Layers are a dealbreaker. Rendering at higher resolutions will make the aliasing less noticeable though.

“Straight Alpha – Unmatted” enabled, the Render Layer edges don’t show fringing (black matting), and the green background color bleeds through the anti-aliased gap between the two Render Layers.

“Premultiplied Alpha – Matted with Black” enabled, the Render Layer edges show black fringing, and the green background color bleeds through the anti-aliased gap between the two Render Layers.

“Aliased – Opaque Fringe” enabled, the Render Layer edges show opaque and aliased fringing, and there is no gap between adjoining Render Layers, so that the green background color does not bleed through.

Render Layer “Body Panels”

Render Layer “Black Parts”

Render Layer “Flames”

Render Layer “Wheels”

Render Layer “Tires”