Red Screen
Fullscreen tool for display testing. Works in-browser, no signup.
Red
Pure red — isolates dead red sub-pixels invisible on white or mixed colors.
Press Esc to exit
About this tool
Full red channel at maximum intensity. Each color pixel is made of three sub-pixels (red, green, blue). If a red sub-pixel is dead, it looks fine on white or yellow but shows as a black dot on this screen. Combine with the green and blue screens for full sub-pixel coverage.