Is medieval BLACK ARMOUR better?

If Monty Python is to be believed, it may confer increased resistance to pain.

Never underestimate the power of looking cool.

Showing wealth was Life insurance. In a pinch being worth a ransom could save your life

He neglected to mention the chief true advantage of blackened armor..."The Black Knight always triumphs!"

Yes because black armor with brass highlights simply looks amazing

Wearing such beautiful armour is a reminder that none shall pass.

Another advantage of blackened armour is its slimming effect. After all, it is very important to remain stylish on the battlefield.

I'm not a chemist, but I know a bit of the science behind it. Iron has a couple common ions +2 and +3, I believe). Magnetite and rust are the two most common oxides of iron. Rust expands when it forms, which weakens the metal and causes it to flake off. Magnetite does not. When you blue steel, you're converting the outside into magnetite, which is mostly done for aesthetics, but does offer added rust/scratch resistance. It's worth noting that cold bluing (the paste you mentioned) doesn't create a very deep or protective finish, so it's best used for touching up a damaged finish. As I understand it, historically it was done by burning pitch onto armor, and largely by less-affluent knights to reduce the necessary maintenance for their armor.

Regarding heat and black armour: The people who did do the research were the gentlemen involved in making air-cooled cylinders, originally on aero-engines but adopted by British motorcycle manufacturers. They found that blackened metal loses heat faster than unfinished metal, both with steel and aluminium and even when that blackening agent is a film of paint. So, going by that, black armour should heat up in the sun quicker, but at the same time any good absorber of radiation is also a good radiator, so it'll cool down quicker too. That's all based on reading in old books, though, and experience has taught me that old books sometimes contain old bollocks, so bear that in mind.

Till ten years ago I did a lot of Napoleonic and medieval reenactment. A friend of mine was an archer and was a very, very proud owner of a shiny, blued armour. You was even not allowed to point at it... So on the evening before he got married his house burned down. All he could save was his bride. Only his armour survived intact...however the chlorine fumes of the burning carpets in his house totally rusted the exposed surfaces in a very, very corroded and pitted way. Parts of the armour that were covered by other stuff were still shiny blue. We ended up painting the whole thing black...

Matt's really trying to sell his armor, eh? Made an entire video to hype it up 🤣

Bro what I would do to have a shed full of swords and multiple armour pieces he’s living the dream well earned too

I’m reading Ian Mortimers book “1415 - Henry V’s Year of Glory” at the moment, and it covers the preparations of the French forces in Paris as the Burgundian Duke John the Fearless approached with his men. He says: “ … the provost of the merchants had prepared four thousand black padded jackets and four thousand axes with blackened blades …”. This was so they could kill the Burgundians without being seen if they tried to enter the city at night …

My house fire illustrated the protective value of blackening. There was a dagger setting on a counter in my bedroom right under a skylight. The firefighters broke that to let smoke out, which drew a lot of the nasty chemical smoke from burning plastics and foams and fiberglass through there. I had made this dagger to have a polished blade and guard. Not highly polished, to 2000 or 3000, but I had blackened the guard. The method I had used was to get it to below glowing heat, not even a dull red, and 'paint' it with soybean oil, repeating this quite a few times. Yes, the same way you'd blacken a new cooking pan. Well the smoke, steam, and firefighting chemicals turned the blade a most vivid orange while the blackened guard was perfectly fine besides the layer of soot on one side. Truly remarkable. However, I had a sword near it that also had a blackened guard but faired much, much worse. I had blackened that one simply by bringing it to a dull red several times. It was not a polished surface first. The blade faired better because it was in a wooden (and linseed oiled) scabbard but the guard has some deep dark red rust now. (Most of the surfaces also were coated in linseed oil as my go to protectant.) So there is one more anecdote around black oxides protecting from other oxidation.

The blackened armor will absorb heat faster than the bright armor; BUT it will shed heat faster. That's why the SR-71 was painted black. The engineers who worked on it discovered that, while light colors reflected heat they also retained that heat, whereas black absorbed heat quickly, it also shed it just as quickly.

I live on a boat. My swords and knives are constantly trying to rust, but my blackened great helm never does...

I'm curious as to how common painting armor was in Europe. It's reminiscent of lacquering samurai armor, because Japanese summers are dreadfully humid. A similar method of purposeful oxidization they used is called "sabitsuke", which was, and still is, often used to darken tsuba.

Darkened armor would stand out a lot in a pack of silvery armor men. As your said, it might be a status thing, but the first idea that sprung into my mind was identification. It might make it easier to "locate the boss, keep close to him, protect him", or "follow your commander in battle". Bonus effect if there is another color on top of it (fancy plumes, golden stuff). On the flipside, it might attract the attention of plenty of enemy crossbowmen...

You looked ferocious in that harness and it's a damn shame you're wanting to sell it.

I don't have experience with blued armor, but with carbon steel knives, the patina is a real bear to work with because if it gets rusty (and it often does), then you have to polish it off with steel wool, and that leaves a silvery spot with neither rust nor patina. Then you got to re-patina it with some vinegar or lemon juice soaked onto a towel. I imagine that if you have a squire to polish your armor constantly, then a burnished silver look would be the easiest to work with. I doubt they had people to re-apply the patina constantly back then.