I am not sure that Chris Gatum really undestands the matter of image resolution, image size and printing when he responds in this week's "Ask AP". In his defence, however, his misconceptions are very widely shared by writers and others. If I take a photograph with my Nikon D800, the image file measures 7360x4912 pixels. At that stage there is no ppi (or, of course, the totally unrelated dpi) involved. The resolution is 7360x4912. Full stop. If I use software to display that image on a computer monitor, I will probably want the software to downsize the image to give the best fit on my screens, both of which have a resolution of 1680x1050. The image on the screen will probably be around 1575x1050 pixels. It is only then that ppi has any meaning. If the image on my screen measures 18" x 12", then it is being displayed at around 87.5ppi. But - and this is the important but - that 87.5ppi is not in any sense a parameter of my image file. It is simply a characteristic of the way my software displays it on my monitor. If I want to print from that file, then my printer software and firmware will translate my image file to suit the parameters I have set for printing. It is quite likely that I will print at my printer's default of 300dpi. This bears no relation whatsoever to the 87.5ppi that I am seeing on my screen. How "big" a file, in terms of pixel dimensions, I need to produce a high quality print depends upon many factors - to name just a few: the number of ink cartridges in my printer, the dot pitch of the print head, the spacing between dots, the surface tension of the inks, the algorithm that my printer software uses to blend colours, the surface characteristics of the paper I use, etc., etc., etc. The main point that I want to make, however, is that the dimensions of the image file (not ppi or dpi) that will give me a great quality print are much less than any of the pundits seem to suggest. If, after processing and severe cropping, I am left with an image measuring 2000x1500 pixels, my Epson R3000 printer using Epson's own profile will produce a 16"x12" salon-quality print easily. That's a lot different from Chris's calculations. And the question of ppi does not enter the equation at all; the question of dpi is merely concerned with how my printer prints and is not a function of the image file. But don't feel too bad about it - it is relatively recently that Adobe sorted out the diffence and non-relationship between ppi and dpi.