Savageduck
On 2014-09-19 19:02:24 +0000, Sandman <mr@sandman.net>said:

Sandman
In article <87vbojttf4.fld@barrow.com>, Floyd L. Davidson wrote:

nospam
In article <bc792678-99f5-4416-8002-0d75afbeadf2@googlegroups.com>,

Whisky-dave
Do you happen to know whether or not this preview file is a copy of the original file but 'rendered' at 72DPI rather than the final copy which is mostly likely to be 300+ DPI for printing ?

nospam
there is no dpi or more accurately ppi until you print. everything is always done to the original image.

Floyd L. Davidson
Until you print... or display an image on a monitor screen. Same thing, and a different value for DPI/PPI.

Sandman
Now Floyd thinks the DPI information saved for an image file is in any way related to the physical PPI of the screen. Isn't he adorable?

Savageduck
Hell! 72 ppi, or 360 ppi makes no difference on a display, but try that with a printer and the result is going to be quite obvious.

I usually open all my RAW images from ACR @ 360 ppi, and

if I am making a round trip from LR to PS they take that trip at 360 ppi. If I am saving, or exporting for display/web sharing they usually go out at 72 ppi, but mostly I don't bother, and they end up out there at 360 ppi.