How can developers ensure optimal visual performance when testing web games on different displays?

When integrating complex game mechanics through a platform's API, ensuring that the visual output remains consistent across various monitor types is a common hurdle for many developers. While discussing technical implementation on forums, do you believe that using a specialized BlackScreen is a reliable method for identifying hardware-specific issues like backlight leakage or pixel defects that might ruin the player's immersion? Beyond standard debugging, what specific display calibration tests do you recommend to others to ensure their game’s dark scenes and contrast levels are perfectly optimized for a global audience?