In an 8-bit RGB image, each channel (R,G,B) ranges from 0 to 255. Equal intensities in all three channels produce a neutral colour (no hue):
- (0,0,0) $⇒$ black,
- (255,255,255) $⇒$ white,
- any equal mid-level like (127,127,127) $⇒$ mid-gray.
\[
\boxed{\text{gray}}
\]