On Wed, Jan 14, 2009 at 11:58:47PM +0200, Leonard Mada wrote: >> I can't believe that a 1000*1000 image looks the same full-scaled on >> a proper inkjet a4 or letter-sized printout. > > Lets take a colour image printed on a home-printer => it will have at > most 100 LPI (actually more like 80-90). > > 11.7*100 = 1170 > 8.3 *100 = 830 > > So, a 1170 x 830 pixel colour image will print optimally on any > home-printer. > > Lets take now a professional image-setter with 150 LPI: > 11.7*150 = 1755 > 8.3 *150 = 1245 > > Any resolution higher than this is NOT useful, as the printer driver or > printer processor will firstly scale down the image and then print it. > In order to construct the various colours, the printer combines lots of > dots, i.e. a 600 DPI will combine at least 6*6=36 dots to create 37 > levels of gray (it is similar - though more complex - for colour > prints). > Hi Leonard,
not sure what you're referring to as a "home-printer", but 2880 dpi is becoming standard for better inkjets, as well as hexachrome or other more-than-four-color systems. Do the math, add halftoning/dithering and the fact that inkjet technology is able to mix color in a single spot - I'm sure I'll be more happy having the printer driver doing the down-scale & catering for the process specificities than Impress (I don't even mention mention monochrome images, where surely the printer can use its full dpi). This is not to say that I want Impress to be a professional image manipulation program; it's merely cautioning us to hard-code a value that has been come by via a very limited experiment (that did not even include inkjet printing), without asking the user & in an environment with ever-increasing resolutions... Cheers, -- Thorsten --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
