Match Alpha
What It Does
The Match Alpha node calculates the opacity value needed to blend a foreground color with a background color to match a reference color. It reverse-engineers the alpha value that would create the target color.
Inputs
| Name | Description | Type | Required |
|---|---|---|---|
| Foreground | The color to apply transparency to | Color | No |
| Background | The background color for blending | Color | No |
| Reference | The target color to match | Color | No |
| Threshold | Maximum allowable color difference (0-1) | Number | No |
| Precision | Calculation precision for alpha value | Number | No |
Outputs
| Name | Description | Type |
|---|---|---|
| In Range | Whether a valid alpha value was found | Boolean |
| Color | The foreground color with the calculated alpha | Color |
| Alpha | The calculated alpha value (0-1) | Number |

How to Use It
- Drag the Match Alpha node into your graph.
- Connect your foreground color (like
#5C5656), background color (like#FFF), and reference color (#CFCDCD). - Adjust threshold and precision if needed (defaults are 0.01).
- The node outputs the calculated alpha value (0.3) and the semi-transparent foreground color (
#5C56564D). - If "In Range" is false, no suitable alpha value could be found.

Tips
- Lower threshold values require more exact color matching.
- If no suitable alpha is found, try different foreground and background colors.
- This node works best when the reference color is between the foreground and background colors.
See Also
- Flatten Alpha: For the reverse operation - merging a transparent color with a background.
- Contrasting Alpha: For finding alpha values that maintain contrast requirements.
Use Cases
- Color System Analysis: Discover the transparency values used in existing designs.
- Overlay Recreation: Recreate the exact transparency of an existing overlay or glass effect.
- Color Harmonization: Find transparency values that harmonize colors in a composition.