1hew-ComfyUI-1hewNodes/web/docs/1hew_ImageAlphaSplit/en.md

Image Alpha Split - Extract alpha and flatten to background

Node Purpose: Image Alpha Split extracts the input image alpha as a mask output, while also compositing transparent areas onto background_color and returning the processed RGB image.

Inputs

Name	Port	Type	Default	Range	Description
image	-	IMAGE	-	-	Input image, supports single image or batch; RGBA inputs extract alpha and composite against the background color
background_color	-	STRING	1.0	same formats as Image Solid color: named / #RRGGBB / r,g,b / 0~1 grayscale / single-letter shorthand	Background color used to fill transparent areas

Outputs

Name	Type	Description
image	IMAGE	RGB image flattened onto the selected background
mask	MASK	Alpha mask extracted from the input image; becomes a full-white mask when the input has no alpha

Features

• RGBA input: returns the original alpha as mask and composites transparency onto background_color.
• RGB input: passes image through unchanged and returns a full-white mask.
• Batch support: image batches are processed frame by frame and return synchronized image and mask outputs.
• Color parsing follows the same rules as the Image Solid node.

Typical Usage

• Split alpha from transparent PNGs while also generating a background-filled preview or downstream-safe RGB image.
• Prepare white-background images for nodes that do not support alpha, while keeping the transparent area as a mask.
• Standardize batch workflows that need both a flattened image and the original alpha mask.

Notes & Tips

• The image output is always RGB and does not preserve the original alpha channel.
• If the input image has no alpha channel, mask becomes fully white and background_color does not affect the image result.