Were there two hero ESB Helmets for the production of Empire Strikes Back?
As I'm watching the movie, there seems to be one helmet that has a brighter gun metal gray, and then another helmet (once they're at City in the Clouds) that's much more dark - a charcoal gray to go with the black. The gun metal in the nose tip pops so much more in these CitCs scenes, and the rest of the helmet seems so much more dark and brooding.
Then when Vader returns to his Star Destroyer at the end of the movie, as he's having his mind melt with Luke on the Falcon, it appears as though he has brighter gun metal two-tone'd helmet.
Edit:
This screen grab is from Vader Star Destroyer at the end of ESB. You can clearly see the two tone difference - the definitive black pain over the arch of the nose (I wanna call it a snout LOL), the silver/gun metal to the left and on the bridge between the eye lenses. The tip of Vader's snout doesn't pop as much here, but you can see how the tip's silvery paint matches better with the paint on the top of Vader's wearer's right cheek, and the neck extension.
Vader's dome also looks it's most glossy and polished here.
This screen grab is from Cloud City - the second part of Vader's duel with Luke - just after Luke flies out the broken window. You can see how the silver in the snout tip pops, but no other portion of the paint on the helmet pops in the same manner. Some might want to chalk this up to lighting, but the front of the wearer's left cheek would pop the same way as the snout tip and to a lesser degree than the tusks. But that cheek doesn't.
To me, this is the most telling... Vader's dinner party.
The snout tip is clearly popping from any other color/tone on Vader helmets (save for the tusk tips). The rest of the two-tone paint scheme is much more balanced and less visible. There's fairly even lighting coming from all sides as the overhead light is bouncing around off the light colored walls.