To my knowledge I am not color blind, however, I never see red in hot steel only shades of orange to yellow then white. I see cherry red on color charts, red cool aid, blood, etc., never in steel. I think I've seen red in a YouTube video of steel never in my forge or on hot metal as it cools through the spectrum

Working outdoors in the daytime you will never see the true colors in the steel. At night or stuck in a barrel with the inside painted black, the real heat colors will pop out at you.

Depends on how much light, bright light only orange and up. At night, or under a hood, all the way down to dark red.

Dim room and maybe a shadow box and NO tinted safety glasses will make the color clear enough that if you still can't see them you need to have your eyes checked.

 

Frosty The Lucky.

Assuming the set-up is right for allowing a normal person to see heat colours, there are some medical / physical conditions that may prevent other individuals from not being able to do so. Colour-blindness is commonly known of, but some people don't mistake colours for other ones, they simply can't register a given colour at all. This may be due to an inherent problem or due to later injury and damage from.

When I need to be that precise I close the big door to my forge. It helps alot. If you are outside forget it. You won't see it until it's real hot.

I think of it as the same as watching a sunset as far as the color range I see as a piece cools. Having black out curtains over the windows during the day time helps. Should be able to see the black shadows of desaclence too.