The color of the flame

I am fascinated by the color of the fire. OK, I’m fascinated by fire, but right now I’m thinking about the color of the fire.

I made a fire tonight and for a long time it was an orange flame. It seems to me that an orange flame is what I call an ugly fire, a dirty burning fire. Mary has suggested that the amount of daylight determines the color of the flame. And I admit that as it gets darker outside the colors become more visible. But Tiernan and I have seen all kinds of color in full daylight. As night fell, the orange softened, but it was still an orange-ish flame.

I like the yellow flame. It seems cleaner, and hotter. I got to yellow for a little while tonight. When I have a yellow flame I know I have a really good fire.

We have occasionally seen green flames (not tonight). It usually occurs when we are burning boxes and seems to be the ink, but we have seen it from wood. That is the most interesting flame – “Look, it’s green!”

The prettiest flame is blue. And it’s funny how the blue is always at the bottom of the flame, usually a yellow flame. At the end of my fire tonight, there were blue flames dancing all over the remaining wood, even when they were not topped by yellow.

Here’s my conclusion as to heat and the color of the flame. This is from coolest to hottest:

Red

Orange

Yellow

Blue

(I don’t know what to think of that pretty green flame.)

After my observations, I googled “flame color” and found this

“Flame color depends on several factors, the most important typically being blackbody radiation and spectral band emission”   I understand everything up to "factors"!

“In the most common type of flame…the most important factor determining color is oxygen supply and the extent of fuel-oxygen pre-mixing, which determines the rate of combustion…thereby producing different color hues.
In a laboratory under normal gravity conditions and with a closed oxygen valve, a Bunsen burner burns with yellow flame... With increasing oxygen supply, less blackbody-radiating soot is produced due to a more complete combustion and the reaction creates enough energy to excite and ionize gas molecules in the flame, leading to a blue appearance.”
I think this means blue is the result of more oxygen and cleaner burning. Hotter fire.

“The colder part of a diffusion (incomplete combustion) flame will be red, transitioning to orange, yellow, and white as the temperature increases….”
Hey, that is what I observed! With only one eye, too!!

This article also said something about visible light spectrum. This is so cool.

Here is the illustration they offered

“Different flame types of a Bunsen burner depend on oxygen supply. On the left a rich fuel with no premixed oxygen produces a yellow sooty diffusion flame; on the right [4] a lean fully oxygen premixed flame produces no soot and the flame color is produced by molecular radicals, especially CH and C2 band emission. The purple color is an artifact of the photographic process.”