RGBA
A colour model that adds an Alpha channel to the standard RGB colour space to represent transparency.
RGBA is the four-channel colour model used by every modern background-removal pipeline. RGB stores the colour information (red, green, blue) and A stores the alpha (transparency). When a designer says 'this PNG is 32-bit RGBA', they mean each pixel has 8 bits for red, green, blue, and 8 bits for alpha — a total of 32 bits per pixel.
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RGBA is the four-channel colour model used by every modern background-removal pipeline. RGB stores the colour information (red, green, blue) and A stores the alpha (transparency). When a designer says 'this PNG is 32-bit RGBA', they mean each pixel has 8 bits for red, green, blue, and 8 bits for alpha — a total of 32 bits per pixel. The model is the de facto standard for any image that needs transparency.
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RGB has three channels (red, green, blue) and every pixel is fully opaque. RGBA has four channels (red, green, blue, alpha) and supports per-pixel transparency. For web and design, RGBA is the default for any image that needs transparency.
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In CSS, rgba(255, 255, 255, 0.5) is a 50% opaque white. The alpha value is between 0 (fully transparent) and 1 (fully opaque). Older CSS uses the 'opacity' property on a separate element; modern CSS prefers rgba() or hsla() for per-pixel control.
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32-bit PNG uses RGBA. WebP uses RGBA. JPG does not (it is RGB only). PSD supports RGBA per layer. When exporting a transparent image, always pick a format that supports RGBA or the alpha is discarded.
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RGBA images are 33% larger than equivalent RGB images (4 channels vs 3). For most web and design work, the trade-off is worth it for the transparency. For high-resolution photographs that do not need transparency, JPG or RGB-only PNG is smaller.
RGBA = Red, Green, Blue, Alpha — the four 8-bit channels that make a 32-bit image. RGB-only (no alpha) is 24-bit.
Continue learning
What is an Alpha Channel?
The technical deep-dive on the alpha channel.
What is a Transparent PNG?
The full glossary entry on PNG with alpha channel.
PNG vs JPG vs WebP
Format-by-format breakdown for the web, print, and product photos.
Apply this to your workflow
BGRemover turns the technical parts of background removal into a single click. Open the workspace and see the difference.