Thanks, Paul. I found an earlier contribution of yours in the archives. > I must take issue here - it is arithmetic! If you use a print resolution > of 1440dpi (dots per inch) in order to achieve 256 levels of colour you > need a cell size of 16x16 dots. There are 90 of these to every inch. > Good printing practice says the original file should be twice this to > ensure that you achieve the best sampling (if the file were 90ppi you > might sample one pixel twice and then miss the next one...). Double 90 > give you the 180ppi that Epson told you.
I am not sure about the arithmetic though. My understanding is that native resolution along the printhead axis is 720 dpi with all these printers, and it is the stepping increment which gives 720, 1440 or 2880 dpi along the paper transport axis. That with variable droplet size makes the picture a bit more complicated. You are right that that it's worth doing some tests. I have already found, using the same test chart, that my 300 dpi Canon CP-300 dye-sub printer is aliasing at a lower spatial frequency than the Epson 1160. Now to get more quantitative answers. Tim Mimpriss =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
