Why Do PNG Logos Turn Black When Converted to JPG?
A common and frustrating surprise when converting a company logo, brand watermark, or graphic illustration from PNG to JPG is watching transparent backgrounds turn into an opaque, solid black block.
This happens because of a fundamental architectural difference between graphic containers:
- PNG (Portable Network Graphics): Uses a 32-bit RGBA color model containing 8 bits of Red, 8 bits of Green, 8 bits of Blue, and an 8-bit Alpha channel that defines pixel opacity from 0 (100% transparent) to 255 (100% opaque).
- JPG / JPEG (Joint Photographic Experts Group): Uses a 24-bit RGB color model strictly limited to photographic colors. It has no alpha channel.
When an unconfigured image converter strips the alpha channel without compositing, transparent pixels (where RGB values are stored as \