rcd@nbires.UUCP (Dick Dunn) (06/22/86)
In reference to problems with fonts looking different on different types of printers: > > I have heard that it is normal. A font printed in a Canon-type printer > is really bolder than the same on a Xerox-type. We have observed comparable differences on a Canon engine vs a Ricoh engine. I'm told that these two printers differ in one being "write black", the other "write white," and that this makes the difference in the appearance of fonts. I know some of the very basics, such as that the "resolution" (spacing of pixels) is different from "spot size", and that the way the toner fuses affects some things, but I'd really appreciate someone who understands the technology posting a little explanation. > So, I am looking for people who have the same problem and the "method" for > solving it. Is there a special distribution of 300 pixel/inch fonts for > Xerox-type printers, or programs to enbold standard TeX 300 pixel/inch fonts ? > And what about Troff fonts ? Seems that the solution lies in going back to however the bitmaps for the fonts are generated and regenerating them with modified algorithms. In what we were doing, the lighter printer tended to allow lines to break up where a stroke was one pixel wide for a distance of more than two pixels or so. When strokes break like this, it's more than just a little annoying or a little "too light"--it actually gets distracting and hard to read. -- Dick Dunn {hao,ucbvax,allegra}!nbires!rcd (303)444-5710 x3086 ...Simpler is better.
SofPasuk@imagen.UUCP (06/23/86)
> In reference to problems with fonts looking different on different types of > printers: > > > > I have heard that it is normal. A font printed in a Canon-type printer > > is really bolder than the same on a Xerox-type. > > We have observed comparable differences on a Canon engine vs a Ricoh > engine. I'm told that these two printers differ in one being "write > black", the other "write white," and that this makes the difference in the > appearance of fonts. I know some of the very basics, such as that the > "resolution" (spacing of pixels) is different from "spot size", and that > the way the toner fuses affects some things, but I'd really appreciate > someone who understands the technology posting a little explanation. > > > So, I am looking for people who have the same problem and the "method" for > > solving it. Is there a special distribution of 300 pixel/inch fonts for > > Xerox-type printers, or programs to enbold standard TeX 300 pixel/inch fonts ? > > And what about Troff fonts ? > > Seems that the solution lies in going back to however the bitmaps for the > fonts are generated and regenerating them with modified algorithms. In > what we were doing, the lighter printer tended to allow lines to break up > where a stroke was one pixel wide for a distance of more than two pixels or > so. When strokes break like this, it's more than just a little annoying or > a little "too light"--it actually gets distracting and hard to read. This problem is very real! At IMAGEN, we try to solve the problems in two ways: (1) For fonts, we have Type I fonts for Canon (write black) engines, and Type II fonts for Ricoh and Xerox (write white) engines. The Type II fonts are emboldened by at least one pixel for most glyphs smaller than 14 pt. (2) Our Image Processor software automatically "widens" 1 and 2 pixel wide vectors when producing images for the write white engines, thus preventing "disappearance" of vectors that would be visible on write black engines. Note that textures are a real problem. They cannot be artificially "souped-up" for write white engines and retain their original spacing and visual characteristics. Also note that the Ricoh engines' write white problems are less severe than those of Xerox. Xerox engines must be VERY CAREFULLY TUNED. We have seen some cases of horizontal and vertical pixel widths differing due to mistuning!
henry@utzoo.UUCP (Henry Spencer) (06/25/86)
> ...I'm told that these two printers differ in one being "write > black", the other "write white," and that this makes the difference in the > appearance of fonts... In theory, bits in memory define where the black/white edges on the paper should go. The laser reproduces that pattern of edges on the drum, which picks up toner in that pattern and transfers it to the paper. "Write white" systems pick up toner in areas which were dark, "write black" picks up toner in areas which were illuminated. In principle, this should not make a difference. Except that it's not that simple. (1) The electronics feeding the laser won't turn on and off instantly, and neither will the laser. Probably not significant, it's fast enough. (2) The spot the laser traces on the drum is not square. It's round. (3) The spot the laser traces on the drum does not have perfectly sharp edges, because the light won't focus infinitely well. More serious. (4) The drum's response to light isn't perfect, in particular on the fuzzy edges of spots where only partial illumination is received. (5) Light doesn't always go exactly where you put it, because the drum material will reflect and diffuse it a bit. It tends to spread. Which means that write-black machines tend to widen strokes and write-white ones tend to narrow them. (6) The pattern of light on the drum isn't perfectly reflected in the pattern of charge on the drum when it reaches the toner, because charge leaks off and wanders around a bit on its own. (7) The toner itself won't necessarily stick to the edge of a charged area as well as it sticks to the middle. (8) The later processes, like transferring toner to the paper and fusing it on, may also rearrange the toner a bit. It might tend to spread or contract. In short... "The amazing thing about a dancing bear is not how well it dances, but that it dances at all." To get optimal results, a font needs to be custom-tuned for a particular print engine. -- Usenet(n): AT&T scheme to earn revenue from otherwise-unused Henry Spencer @ U of Toronto Zoology late-night phone capacity. {allegra,ihnp4,decvax,pyramid}!utzoo!henry
robert@gitpyr.UUCP (Robert Viduya) (06/26/86)
Has anyone converted the TeX fonts to work on a Xerox laser printer? We're trying to get TeX working on our 9700 and I'm not satisfied with some of the fonts at all (skinny W's, M's and N's). I'm not looking forward to examining each and every character in every font (128 chars by >400 fonts) and fine tune them by hand. Would this be easier if I had the Metafont input files and a Metafont compiler? robert -- Robert Viduya 01111000 Office of Computing Services Georgia Institute of Technology UUCP: ..gatech!gitpyr!robert BITNET: CC100RV @ GITVM1