Vintage Gillette Blade Questions

Ok,
From the advertising I have seen and the vintage blades I have accumulated over the years I figure that Gillette made two different blades in the 30's and 40's

Gillette Blue Blades
Gillette Thin Blades


What was the difference between the two other than the color of metal?

Was the Thin a lower cost blade and the Blue Blades the upper end of the scale? I mean upper end pricewise as I am certain that BOTH blades would shave like crap compared to modern Gillette Green/Yellow and Super Thin blades as well as all other modern coated stainless blades.

Any info appreciated.
Wp

I am not sure as far as the pricing goes, but can assure you that they do shave like crap. So do the Schick "Thin with Krona Edge" in the blue and white package. They just did not hold up as far as microscopic rust is concerned. I wonder if you used one of those rotary DE stroppers if it would make them any better though.