Although I'm no expert on your printer (or inkjet in general) I believe Jim is right. There is simply no NEED to print halftone patterns. This pattern is used to make films for b/w printing in the old days (and today for very cheap, low quality 1 color printing). Has nothing to do with how an inkjet printer works, but more to do with making separation films for printing. The issue with lpi in general is irrelevant for inkjet but still relevant for files going to 4 color printing(were several posts on this last week or so). What you need to be concerned with IMHO are; the original scan and/or input, number of colors/quality of inks printer is using, ppi of original file, the file's Ppi in ratio to the printer's Dpi. Dots per inch on an inkjet printer are much smaller than the pixels in a file - generally 1/3 the size - though this varies in regard to the printer. As said in another post you must work w/your printer's software to determine what dpi settings it can generate (and on what particular paper's) and connect those to your original scan, then actual file size. Lastly, 2400 x 1200 is not a dpi value but the number of dots the printer can make vertically and horizontally at a given size, probably 8 x 10 in. Personally I'd test to find my best results from a particular file size.
Confusing? You bet. Like someone else said you must find the hard data on your printer and go from there.
Norman
Gregory Fraser wrote:
I have a Canon FS-4000u scanner and an i850 2400x1200 dpi printer. The scanner has taught me that I need to pay far more attention to focusing and all my local color film labs are butchers. That scanner really picks up the scratches well.
When I check the halftone screen settings on the printer I see Canon's default lpi is 45. From what I understand the halftone screen resolution should be approximately one third of the resolution of the output device. So I'm wondering why Canon would set the default screen resolution so low? There is a screen for each of CMYK so do you add the four screen resolutions together to get your final resolution? Even so, that works out to 180 lpi which still falls far short of one third of 2400. I cannot find anywhere that I can set or even find out the actual print resolution in dpi so it could very well be that the printer is only printing at say 135 dpi although the images it produces seem pretty good for 135 dpi.
I suspect I misunderstand this entire process so if someone can set me straight, I would appreciate it.
Greg Fraser
-- Norman Jackson Ford - / PhD (ABD)/ Dept. of Comparative Literature (and Cultural Studies), _University of Hong Kong_
/Visiting Lecturer,/ HD in Multimedia the Art School, HK Arts Centre
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