I am glad this remains a discussion albeit in the wrong thread
. But again I can only ask to not refer to the promo shots but the actual movie. Which I believe should be the reference material as that is what the figure is based on. Pleasaaaase go watch it again.
Also since I am not in a business giving me expertise in color but one that requires me to be rather logic driven.
- would in a true maroon color be perceived as red in any real lighting condition?
This I believe is the question that needs answering as I see red throughout the movie (please watch it before whipping out another promo shot, I now need to know if I am somehow color deficient) and if the above answer to it is no then my conclusion simply cannot be maroon.
You seem to be stuck on the name "maroon". To be more accurate let's call it a medium saturation, medium shade red that pulls more blue than orange. To answer your question: yes. A "maroon" which has a bit of blue in it if shown under warmer (red/yellow/orange) light will appear more more red than under cooler (blue/violet/green) lighting conditions. Bear with me my color theory may be a bit rusty.
Basic subtractive color theory which is where white is the absence of color and black is all colors goes like this. This also broadly holds true for additive color or "light".
Red>Orange>Yellow>Green>Blue>Violet>Red
The Mark III suit falls more to the right side of the line while the Mark IV-VI fall more into the left side of the line. Basically if you want something Yellow to look Green you can light it with Blue lights and it will go Green. In the case of the Mark III you have a more complex color that's mostly Red (of course also with black and white leaning more towards black) but also has a touch of Blue/Violet in it. So if you light it with yellow light it will pull out some of that blue or if you go with red/orange light it will add to the red that's already there making it brighter.
With modern color timing a lot of this isn't super meaningful anymore but lights generally cause the following color variations, again don't take this as gospel. While I do have a lot of training in the arts I'm not super up on my movie-making lights.
- Halogen is among the truest "white"
- "White" LED pulls a lot of blue in most cases depending on the quality of the light and also can cause a drop in color intensity
- Sodium lights pull yellow hard. A lot of period films have that look as it emulates candle light pretty well. The one I always remember is the second Crow movie. It's all lit with sodium lights and it makes it appear very warm and yellow.
- Fluorescents pull green hard. All of the stuff in the first Matrix film inside the Matrix was shot under fluorescents and not color corrected which is what gives it that sickly green color.
- Incandescent lights pull orange/yellow.
- Sunlight can either really push blue or yellow depending. I've had to correct for both when taking photographs.
There's a bunch of other ones as well I'm sure but those are the main ones I'm aware of.
I disagree with your assertion that it ever looks bright high saturation low black red in the movie. It sometimes looks less violet than other times depending on lighting and how the scene was color timed but it never looks like a bright "candy apple" red. Can you at least agree that it's a different color than the Mark IV?
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. Had. A car ones I had had that color and just was not liking it. To be honest I don't really know what candy red nor hot rod red truly is but just going into this debate the mark comes across as red to me, albeit different shades and hence my concession and my fall back position. 
