Herbert2001 wrote:
JJMack, please read that sentence you quoted more carefully: I never stated Photoshop does any pixel interpolation. But it does interpret the size of any placed file.
All Photoshop does is add a new layer to the current document that contains the placed image file pixels the new layer size may be very different then the documents canvas size..
If the current document is a 6MP camera 3:2 aspect ratio image the document sized is 3000px by 2000px and may be set to 300DPI. If you place into that document a web size 3:2 aspect ratio image file that is 600px by 400px set to 72dpi. The layer added will be 600px by 400px 1/5 the sizes of the documents canvas. Photoshop will not scale of the placed image layer to fit within the documents canvas size for it does. The layer added is 600x400 pixel in a 300dpi document that has a canvas size 5 times larger 3000px by 2000px .
I do not understand what your meaning when you write But it does interpret the size of any placed file.
Also in my example Photoshop did no scaling all the images involved were 512px by 512px and all layer are 512px by 512px. Where do you see scaling in my example. Scaling down to boot when the end result was a 500dpi layer document.
The only time that Photoshop may scale a placed image is after Photoshop create the new smart object layer. If the layer does not fit within the documents canvas size. Photoshop will change the smart object layer associated transform scale from Photoshop 100% default to a lower percent so the layer fits within the document canvas size. If the user Photoshop Preference is set to "Resize Image during Place"
My Photoshop Scripts that use Photoshop Place feature always transforms the placed smart Object layer to 100% scale in case Photoshop may have scaled it, Then the script can get the actual layers pixels bounds. So the script can resize the layer to the size it need to be to fit a location in a collage.