wyatt@cfa.harvard.EDU (Bill Wyatt) (10/26/88)
In article <1988Oct25.175954.8744@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes: > In article <16961@shemp.CS.UCLA.EDU> lange@cs.ucla.edu (Trent Lange) writes: > >An increase from 300 dpi to 400 dpi is a nearly 80 percent increase in actual > >resolution, which I call more than slight... > > It depends. The real question is not how many more dots there are per > inch, or per square inch, but how much better the output looks, other > things being equal (which they often are not in comparing different > printers). Last I heard, perceived output quality is *not* a linear > function of resolution. I agree with Henry, here, but he's used the term `linear' in a way I'd like to clarify. Yes, 400 dpi versus 300 dpi means 1.77 times the number of dots per unit _area_. But resolution is generally measured in lines per millimeter, i.e., in lines per unit length. This means that 400 dpi is 4/3 the resolution of 300 dpi. It does not mean that 400 dpi will be perceived as 4/3 (or especially 1.77) times `better' than 300 dpi. I suspect the dpi would have to be 3 to 5 times better to look `twice' as good. To sum up: Resolution is a linear function of dots (really, lines) per inch. Appearence is _not_ a linear function of resolution.-- Bill UUCP: {husc6,cmcl2,mit-eddie}!harvard!cfa!wyatt Wyatt ARPA: wyatt@cfa.harvard.edu (or) wyatt%cfa@harvard.harvard.edu BITNET: wyatt@cfa2 SPAN: cfairt::wyatt
sho@pur-phy (Sho Kuwamoto) (10/28/88)
In article <1256@cfa.cfa.harvard.EDU> wyatt@cfa.harvard.EDU (Bill Wyatt) writes: >I suspect the dpi would have to be 3 to 5 times better to look `twice' >as good. >[...] >To sum up: >Resolution is a linear function of dots (really, lines) per inch. >Appearence is _not_ a linear function of resolution.-- Sorry to dredge up an old topic here. I believe what someone said about 400dpi not looking that much better than 300dpi, but might this not be a problem with the print engine? And this last statement is all too true. Appearance is *not* a linear funtion of resolution. The Apple ImageWriter prints at 144dpi and LaserWriter output is IMHO definitely more than 'twice' as good, whatever that means. I remember getting blown away by it. Oh, how spoiled we've all become. Now, I want to get rid of the jagged lines in 300dpi LaserWriter output, moan about the lack of a magazine quality color printer, and complain about having only 256 colors at one time on my Mac II. I find that 5 meg of memory is just not as much as I want, my 68020 is too slow, etc. The list goes on. I remember programming my Apple II+ in assembly. 48k was a lot then. -Sho
ed@mtxinu.UUCP (Ed Gould) (10/29/88)
>I suspect the dpi would have to be 3 to 5 times better to look `twice' >as good. > >To sum up: >Resolution is a linear function of dots (really, lines) per inch. > >Appearence is _not_ a linear function of resolution.-- There are other considerations as well. Just because the engine is capable of placing dots every 1/400 inch doesn't mean too much. The size of the dots and their shape is important, too. For example, if the dots are 1/200 inch in diameter, then the added dot resolution might be significant for large characters, but not for small ones. Appearance - real-world resolution, if you will, is the real measure. -- Ed Gould mt Xinu, 2560 Ninth St., Berkeley, CA 94710 USA {ucbvax,uunet}!mtxinu!ed +1 415 644 0146 "I'll fight them as a woman, not a lady. I'll fight them as an engineer."
casseres@Apple.COM (David Casseres) (11/01/88)
In article <677@mtxinu.UUCP> ed@mtxinu.UUCP (Ed Gould) writes: >Appearance - real-world resolution, if you will, is the real measure. Not even that. The output must not only look good (appearance), it must be readable (functionality). These are not the same thing. Great mischief has been done by typographers with and without computers who have confused the two. David Casseres