>>4159605>>4163423DPI if fundamental any time you have to deal with actual sizes. If you wanna put your pic in a word document, the most convenient way is to rescale it (resempling or not) in something like photoshop using the right ppi value. In that way the image will have the correct dimensions in the 4A page, with the proper number of pixel.
The additional bonus is that if you define the ppi number, then the size of the text expressed in pt or mm will became meaningfull!
If you set your screen ppi in photoshop and the expected print size of your photo, then you will be able to have a 1:1 preview of the print size.
And, by the way, it should be reported as ppi and not dpi. ppi is Pixel per inch while dpi is Dot per inch. On a screen is the same thing, but on a printer is not. Usually the dpi count of a printer is the summation of all the colored dots that can be placed in an inch but for each color channel! So the count could be extremelly higher.
