1640SU Photo Scanner Resolution Tests 15
See comparitive review of $1,500 Microtek Artix 1100 here.
(this page will take a while to download (270k, about a minute) over a phone modem)
These scans have all been resized in Photoshop back to 3200 DPI. This way you can compare them on equal ground easily on any browser. In other words, I greatly enlarged the low resolution scans so you could see them easily, and shrunk the 9600 DPI scan to fit with the rest. The 3200 and 9600 DPI scans are phony extrapolations done very well in Epson's software anyway, so there is no more detail in them than the 1200 DPI scan as you will see for yourself.
The film original was a section of 4x5" Velvia of an 8.5 x 11" target photographed at 100:1.
You should be seeing the same things I do here. I see the same image quality at all resolutions from 1200 DPI and up, give or take one step up or down on the target. Each target step represents a 12% change in resolution, which is insignificant.
800DPI is one step less good than the others. I start seeing small levels of aliasing at 720DPI and below. I see variations in contrast and density, underscoring the fact that consistency is something I have not seen in the little I've played with this scanner. THese are all from the same peice of film made right after one another.
The lines per mm that correspond to each pair are:
Set on top right:
Biggest set on bottom left and right:
At 1200 DPI and above I see the 22.5 lpmm pair.
At 800 DPI I see 20 lpmm.
At 720DPI I see 16 lpmm.
At 600 DPI I see 14 lpmm.
At 300 DPI I see 7 lpmm.
Therefore it seems that this scanner resolves 1000 effective DPI.
MacWorld also just tested a bunch of scanners in the December 2000 issue, and the Epson 1640SU was OK but not the best, either.