The native resolution of most Epson printers since 2000 has been 1440 dpi (dots per inch). Dots per inch is not the same thing as pixels per inch (ppi) ... a dot is the size of of the minimum ink spot the printer can generate, but it take multiple spots of the discrete inks overlaid to achieve the range of colors that the printer can manage. 720 dpi, double that spot size, isn't really enough area to image a pixel that can be contributed to by four inks (C, Y, M + Black). As a result the 'native' or 'best' resolution of a 1440 dpi printer in pixels is really better considered as 360ppi.
Epson's driver algorithms make PPI resolutions that are integral multiples of 60 in the range of that maximum resolution point print best (180, 240, 300, 360). These numbers are specific to Epson printers and print drivers; other printers and print drivers may well differ as it is algorithm specific. Bruce Fraser covered this subject in his book on color printing many ages ago and in his workshops. G > On Jul 3, 2019, at 12:18 PM, Postmaster <[email protected]> wrote: > > John wrote: > >> When I was in school, they had iMacs and Epson Stylus Pro 4800 printers. We >> were >> advised to size our images to print at 360 ppi. > > That's because 360 is exactly half of 720, the native mechanical > resolution of Epson printers (newer ones are double that at 1440) and > 2:1 interpolation is simple. > > I do my printing with Qimage software which uses its own resampling > algorithms to convert each image to the native resolution of your > printer at the print size you're making. > -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
