scanner resolution

[ettore]

why any scanner in the market proudly shows a "vertical resolution" just double than the "horizontal resolution" which at the end is the outstanding parameter of the scanner itself, e. g. Epson Perfection 3200 which offers 3200 X 6400?

Shouldn't be the same in both axes?
Thanks Bye
Ettore

[slipe]

The vertical resolution was slightly important back when scanners were 300 X 600. The larger number is insignificant anymore and is just marketing hype. If Epson is offering a 1200 X 4800 scanner an uninformed consumer might think a 1200 X 1200 or 1200 X 2400 would be inferior just based on the numbers. So others have to make more insignificant possible motor stops as well.

The smaller number is usually referred to as the “optical resolution” of the scanner. It is mostly a result of the density of the CCD (or CIS) sensor array.

You are correct that you can’t scan at 1200 X 2400. The highest you could scan without interpolation would be 1200 X 1200. You can only scan with both numbers the same. And if you go above the optical resolution you get no more detail.