Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!brl-adm!rutgers!cbmvax!daveb From: daveb@cbmvax.cbm.UUCP (Dave Berezowski GUEST) Newsgroups: comp.sys.amiga Subject: Re: Getting fonts printed out right Message-ID: <1157@cbmvax.cbmvax.cbm.UUCP> Date: Mon, 22-Dec-86 09:10:55 EST Article-I.D.: cbmvax.1157 Posted: Mon Dec 22 09:10:55 1986 Date-Received: Mon, 22-Dec-86 22:38:47 EST References: <819@ulowell.UUCP> <2179@well.UUCP> <1257@cadovax.UUCP> Reply-To: daveb@cbmvax.UUCP (Dave Berezowski GUEST) Organization: DMB, Inc. Lines: 62 Summary: long but useful! In article <1986Dec20.150147.5558@utcs.uucp> wagner@utcs.UUCP (Michael Wagner) writes: > >Of course, a lot of the problem seems to stem from the fact that no one really >seems to understand how the printer.device really works (aside from Carolyn). >It's documented, in a badly worded piece of fine print, in the RKM. Printing >is important, guys, even for a video machine. I use DPAINT to draw things. >I can't hang the resulting video on the wall. I want to hang the printed >output on the wall. I can't. My OKIMATE 20 colour printer can't get the >shades even close! No where is the half-toning and dithering of the >printer.device adequately described, and I'm convinced it's NOT WORKING! > >Grrrr..... > >Michael As the author of the graphic side of the printer device, let me assure you that the dithering IS working on your OKIMATE-20 printer. You must understand that the final color produced by your printer will depend on the type of paper you use (waxed vs non-waxed), variations in the ribbbons, etc. Also, depending on your monitor and how you have the contrast, brightness, tint, color, etc(wht ever color controls) set, the colors on screen may or may not appear to correspond perfectly to the colors in the printout. Another factor to consider is the medium itself. You view an image on a monitor by the light it gives out, whereas a printed printure is viewed by the light it reflects. Also, there are two types of color mixing going on here (r+g+b) vs (y+m+c and sometimes b). Anyhow, enough of this background stuff, on to the meat. The dithering works on a 4x4 dither matrix which produces 16 possible shades per base color (yellow, magenta, cyan, and black (maybe)). (Your printer doesn't have black, so black isn't used). These base colors are then mixed to produce 16 possible shades of red (y+m), green(y+c), blue(m+c). Since the Amiga's colors have 16 intensity levels (0-15), the translation works very smothly. THE FINAL OUTPUT COLOR IS A RESULT OF HOW WELL YOUR PARTICULAR PRINTER MIXES THE COLORS. Ink jet printers seem to be the best at this as the ink tends to mix before it dries on the paper. The okimate-20 printer can't really mix colors, it simply overlays them. I suppose that since the color is being melted on, that the colors may tend to melt (ie. mix) together, BUT certainly not as well as an ink-jet printer. Your okimate-20 is doing the best it can to represent the colors you see on your monitor (really it is)! I hope that this sheds some light on the subject. Regards, David Berezowski PS. Your okimate-20 produces black by mixing y+m+c. PPS. Another reason cheap (ie. less than several tens of thousands of $$$$) printers can't reproduce colors as well as you'd like is due to a technical limitation. There isn't a 1-1 correspondence between rgb and ymc. That is to say that red may really be yellow + 1.1 * magenta. Since 'cheap' printers don't have the ability to produce variable amounts of the same color, we are stuck at using the 1-1 relationship. I have spoken to serveral printer manf. and they tell me that it will still be years before you see a printer with the above capabilities in our price range.