Comparing TWSBI Pens

Yesterday, I decided to do some sketching to compare my TWSBI pens with a Fine Nib to the ones with Extra Fine nibs.  .

Pens being Compared:

580ALR - Fine nib - Noodlers Lexington Grey (newest bottle)
Eco - Extra Fine nib - DeAtramentis Urban Grey
Mini - Extra Fine nib - Noodlers Lexington Grey (old bottle purchased years ago)

Looking at the results between the 580ALR and the Eco....it's like the nibs are reversed with the Fine acting more like an EF and the EF acting more like a Fine nib.  I think it's more of an illusion due to the ink with the Urban Grey feeding wetter and darker.  The other thing I took notice to is the fact I've read Urban Grey is not known to feather whereas Lexington Grey does.  My results are just the opposite making the lines look thicker with the Urban Grey.

This next one is comparing the 580ALR with Fine nib to my Mini with EFine nib but using the same manufactured color ink - Lexington Grey.  The difference, however, is the 580ALR is loaded with ink from a new bottle whereas the Mini is loaded with ink from an old bottle I've had for years.  It APPEARS the new bottle or batch is warmer in tone than that from the old bottle.  Outside of that, I don't see a major difference in line width between the Fine and EFine nibs.  The difference I did take notice to was the "feel" as the nibs moved across the paper.  The EFine has more drag...a little scratchy compared to the Fine nib.