Hot Spot to Spill Ratio

[BOBBYBOB]

I just heard this term today, would one of you nice gentlemen please
explain what it means. In simple terms please, I am challenged. Thanks

 

[magic_elf]

I believe its simply the ratio of the spot brightness to that of the spill brightness (usually measured in lux).

 

[Beastmaster]

To add - here's a pic of hot spot vs. spill