Scan at 300 dpi gives file at 120 ppi

[Maarten Worp]

Whenever I scan 35mm transparencies at 300 dpi (or even 72 dpi or 480 dpi) the resulting file always has a resolution of 120 ppi. The input values for Height and Width are keyed in for A4-size prints; thus the resulting file at 120 ppi gives output H & W values which are too large (by 2.5 times for a 300 dpi scan). I use a scanner with TWAIN interface.
Why is the output fixed at 120 ppi; how can I get the control over what resolution to use?
Thanks!

[Colin Walls]

This is all very confused.

Normally, slides are scanned at around 2400 PPI [not DPI!!!!]. This yields 3600 or so pixels along the long edge, which means that you have around the 300 PPI desirable for printing [gives 12" - just bigger than A4].

So, how many pixels are you getting?
The PPI setting of the image is only relevant when you go to print. After the scan, the only thing that matters is the number of pixels.

[Gary Hummell]

A good scanning resource:
<http://www.scantips.com/>
Gary

[dave milbut]

what version of ps? I think v6 had problems with resolution tags in the exif data. v7 fixed that.

[Phosphor]

Double-czech unit of measurement complicity from front to back.

Eschew obfuscation!

[Mac McDougald]

If you mean you are scanning slides at 1:1 (actual size) at 300ppi,
that's not enough to do doodly squat with, only gives 425x283 pixels.

These (few) pixels can be rearranged to whatever ppi you want in
Photoshop, but it's not a big enough image for anything but maybe
webwork.

Mac