the Epson Perfection 2450 Scanner

Using a fixed diffused light source for transparency scans, the Epson 2450 resembles an enlarger with a cold light, rather than one with a point source or condenser light system. The scans confirm this observation, providing smooth tonality, differentiating tonal values at both ends of the density spectrum. Examples comparing 35mm scans with the Epson 2450 and the Nikon LS-1000 can be found HERE.

35mm Kodak High Contrast Copy Film

  • "Flat on glass" - the negative was placed directly on the scanner glass with a piece of anti newton glass on top to hold it flat.
  • "Epson Holder" - the negative was scanned with the supplied negative holder and was therefor slightly above the scanner glass.
  • " Nikon Holder" - scanned with film in the Nikon LS-1000 Strip Film holder FH-2 placed on the scanner glass.

 

Scanned at 2400 spi

Scanned at 6400 spi

RED

GREEN

BLUE

RED

GREEN

BLUE

Epson
2450

Epson
Holder

Epson
2450

Nikon
Holder

Epson
2450

Flat
on
glass

Scanned at 2700 spi

Scanned at 5400 spi

Nikon
LS-1000

Placement of the image or transparency for proper focus would seem to be critical. The fact that I get questionable results when placing the negative directly on the glass, prompted me to try a "depth of field" test. Hollerith Cards ("punched cards", or "IBM Cards") were manufactured to extremely close tolerances (0.0067 inch ± 0.0005).

 

A stack of 36 cards (approximately 1/4 inch) was arranged and placed directly on the scanner glass. The theory was that sharpness of the printed word "GLOBE" would indicate the extremes of adequate focus.

 

The lower illustration shows actual 100% views of a 2400spi scan of the cards, with the distance above the glass of each shown in red. The results are shown in grayscale because only the green channel was selected - see the clock results above.

Experiments by others have indicated elevations of 0.0625 and 0.09375. Based on the above illustration, I suspect that I would choose an elevation around 0.04

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