Why does adjustable emissivity matter?

Different surfaces emit infrared differently. Shiny stainless steel and polished metals read low on a fixed-emissivity gun; matte, dark surfaces read closer to true temperature. Specialist communities like r/carbonsteel repeatedly warn that fixed-emissivity guns give misleading readings on shiny cookware, so an adjustable model (typically 0.1–1.0) is worth the small upcharge for kitchen and metalwork use.