As objects are heated they reach a temperature where they begin to glow. First dull-red-hot, then cherry-red, then white-hot. Seems the temperature and color outputted are the same regardless of material. For centuries, iron workers, glass blowers and ceramic potters, have used the glowing color as a marker. The Celsius temperature scale is favored by scientists because it blends in with the metric system.
There seems to be no limit as to how high a temperature is possible, however the lower limit is -273.16°C. It is presumed that if a material is cooled to this absolute lowest possible temperature, molecular motion ceases. The Absolute temperature scales sets -273.16°C as the zero point. Thus all readings will be positive, no confusing negative temperatures with positive. The Absolute scale was renamed the Kelvin scale to honor William Thomas, 1st Baron Kelvin.
K = C + 273.16
C = K – 273.16
All objects above
-268°C --- 5°K Infrared radiation (electromagnetic radiation) invisible to human.
400°C --- 673°K Red heat, visible in the dark
474°C --- 747°K -- Red heat, visible in the twilight
525°C --- 798°K -- Red heat, visible in the daylight
581°C --- 854°K - Red heat, visible in the sunlight
700°C ---973°K - Dark red
800°C --- 1073°K - Dull cherry-red
900°C --- 1173°K - Cherry-red
1000°C -- 1273°K - Bright cherry-red
1100°C --- 1373°K - Orange-red
2525°C --- 2800°K - Yellow
3225°C --- 3500°K - Yellow-White
4225°C --- 4500°K - Warm-White
5225°C --- 5500°K - White
6125°C --- 6400°K - Sky Blue