Originally Posted by recentgrad
While Zegna could use different dyes with their fabrics, I suspect most of what you're identifying as better is having a very glossy finish, which would be a function of the fabric and the weave. Mohair is known for having a sheen and being slightly shiny.
I think what I am identifying as "better" is a combination of all of those attributes that I previously mentioned. I do not think glossy finish is the main factor at all, many high end fabrics are muted with no gloss to them. I was specifically referencing the color as something that differentiates nicer fabrics on a suit from a distance and it really has nothing to do with it being shiny. I used Zegna as an example because they are a well known cloth manufacturer and they have many grades and lines of fabric that could be compared to one another vertically any high end mill/merchant has various "books" on offer and quick side by sides will show you the difference in quality.
Realistically, it is not one thing in particular but a combination. As with any product there are high end and low end materials and when you purchase lower quality component parts it is not going to be as good as the higher end which is why they cost more. Take paint for example, why does one one gallon of cheap Kmart Martha Stewart paint cost $20/gallon and really high end paint go for more than $50/gallon? Better ingredients including pigments so one navy is not going to be the same as the other. Brands have pricing power but there is a reason they are a brand in the first place, because they are delivering a known level of quality to a consumer base that trusts that brand. We might live in a world of increasing brand and quality erosion but there are still companies that stand for something and are not just a brand name purchased by a conglomerate and gutted of the quality that built the brand.
Higher end fabrics cost +$150/yard or more without getting into the stratospheric levels of Vicuna or diamond chips woven into the fabric et al, I am just referencing high quality cloth merchants and mills. If you need 3 to 3.5 yards to make a suit you are talking about $500 in fabric at a minimum, which means you are never going to see those fabrics on a cheap suit, it would be hard to turn a profit if your materials were in excess of 50% of the retail price. These fabrics cost more because they are of higher quality, color, texture, weave etc and not because someone put a nicer label on them. A J.Crew, Hugo Boss, suit supply suit that retails for $1000 can't possibly be produced with fabric that costs even half that which doesn't even account for thread, buttons glue(hopefully the really good glue), marketing costs and of course labor. Those products rely on volume, extremely low wages and bulk purchases of fabric that do not have the small batch "artisinal" qualities you will see with more expensive cloth. Which is why I mentioned fabric in the first place because if a suit has nice fabric you know its expensive without even touching construction, fit, handwork etc. And generally tailors/clients don't invest +$500 of fabric into something that will be constructed poorly so if you see a nice fabric its highly correlated to the overall quality of the suit.
Mohair is more than just a sheen, the material has a different cellular structure than wool and behaves differently on a finished garment, specifically it holds its shape very well and is instantly recognizable with color an texture. I have a few suits in wool/silk/mohair blends so I have some familiarity and they really aren't that shiny and certainly not gaudy, they are perfectly acceptable in a business environment. I was referencing it before because it is a more expensive fiber and not something you typically see on a low quality garment. As with the above there are cheaper suiting cloth made with mohair and there are expensive ones, I have no doubt the expensive ones look better. Cashmere is the same way, as are most other high value fibers it often has to do with the length of the fibers being used. Everything is graded and priced accordingly. Just because something is labeled cashmere or mohair doesn't mean its all the same just as all "navy" colors are not all the same.
I did a quick google search on the color references made earlier and without delving into math and color theory the answer was the human eye can detect up to 10 million colors that to me would suggest there are a multitude of navy blues out there.
I don't think it is even necessary to break it down into scientific elements, you know it when you see it. Your original question was can a person tell/recognize an expensive suit, and as I have already said yes, yes people recognize it immediately. Of course their are outliers like the guy that is as easily satisfied by a Big Mac as he would be eating at Peter Lugers (insert name of high end restaurant) but that isnt within the range of normal.