Forum member @Dualist sent me some blades from his collection that I have put under the microscope for those that are interested. I have never used any of these blades so I cannot comment upon my experience with them, but perhaps @Dualist and others that have experience with these blades will chime in. I am going to start with the Carbon blades. The very first blade is vintage, a Thin Gillette which I believe to be a carbon steel blade. It showed some rust that bled through the wrapper but I did find a section that looked pretty good to scope. It appears to me that there has been some deterioration most likely related to age and improper storage at some point in it's long life.
Thin Gillette 200x
Treet Carbon (aka Black Beauty) 200x
Treet Falcon Carbon 200x
These next blades are all stainless steel to the best of my knowledge.
Treet Classic 200x
Treet Dura Sharp 200X
Bolzano Superinox 200X
Gillette Rubie 200x
Gillette Nacet 200x for comparison to Rubie
Thin Gillette 200x
Treet Carbon (aka Black Beauty) 200x
Treet Falcon Carbon 200x
These next blades are all stainless steel to the best of my knowledge.
Treet Classic 200x
Treet Dura Sharp 200X
Bolzano Superinox 200X
Gillette Rubie 200x
Gillette Nacet 200x for comparison to Rubie