bakken@tahoma.ARPA (Dave Bakken) (10/02/87)
Another A2000 question: Is smearing a problem with a long-persistence monitor on the Amiga (both with the stock Amiga and with a 68020/68881 board)? Would it be noticable only with the fastest of animations, or most/all animations and even routine operations with a WYSISYG word processor or a paint program? -- Dave Bakken Boeing Commercial Airplane Company uw-beaver!ssc-vax!shuksan!tahoma!bakken Disclaimer: These views are my own, not my employers.
cmcmanis%pepper@Sun.COM (Chuck McManis) (10/06/87)
In article <177@tahoma.ARPA> bakken@tahoma.ARPA (Dave Bakken) writes: > >Another A2000 question: Is smearing a problem with a long-persistence >monitor on the Amiga (both with the stock Amiga and with a 68020/68881 board)? >Would it be noticable only with the fastest of animations, or most/all >animations and even routine operations with a WYSISYG word processor or a >paint program? I've seen an Amiga connected to a Sun-2 color monitor (19" LP, 15Khz scan rate) and the smearing was not a problem. Things you could do included zinging the mouse around in a circle fast enought to make it look like there were 20 mice arranged in a circle (talk about your virtual sprites!). This however is not the point, the point is that for things like Draw Plus in interlace mode there is practically no flicker (white and black still flicker but just about everything else doesn't.) And of course animations tend to smear (although just text movement isn't to bad if it isn't all green). The point is that for interlace work the LP monitor is fine, and for animation stuff you want the regular persistence monitor. So you really want *two* monitors, one for animations and one for hi-res work. (Or you want a frame buffer the deinterlaces the video for you.). --Chuck McManis uucp: {anywhere}!sun!cmcmanis BIX: cmcmanis ARPAnet: cmcmanis@sun.com These opinions are my own and no one elses, but you knew that didn't you.
miner@dino.cpe.ulowell.edu (Rich Miner) (10/07/87)
In article <177@tahoma.ARPA> bakken@tahoma.ARPA (Dave Bakken) writes: >Another A2000 question: Is smearing a problem with a long-persistence >monitor on the Amiga (both with the stock Amiga and with a 68020/68881)? Long-persistence monitors _do_ smear. It is noticeable with scrolling text and animated objects. For editing it is a decent solution, but is still an annoyance. I anticipate the arrival of better solutions, scan-doublers, hires color graphics cards and hi-res monochrome solutions. >Would it be noticable only with the fastest of animations, or most/all >animations and even routine operations with a WYSISYG word processor or a >paint program? It is noticeable on most animations. Word processors and paint programs, not so much, but your mouse pointer will have a little tail. Smear vs Flicker? I say purchase a multi-sync monitor and wait a few months. -- Rich miner@ulowell.edu 617/452-5000x2693 ULowell CPE Imaging Research Lab
whitcomb@ic.uucp (Gregg Whitcomb) (10/07/87)
In article <1767@dino.cpe.ulowell.edu> miner@dino.cpe.ulowell.edu (Rich Miner) writes: > >Smear vs Flicker? I say purchase a multi-sync monitor and wait a few months. >-- >Rich miner@ulowell.edu 617/452-5000x2693 ULowell CPE Imaging Research Lab I just received my B2000 (It's hard to believe after all the waiting). Since I couldn't decide on a monitor when I ordered it, I decided to use an old <$100 zenith monochrome (amber) monitor which has been sitting idle for two years. I was VERY impressed with the quality of the picture the 2000 produces with it! (Great job GR and C= !). I was also able to reduce flicker almost entirely by adjusting the "colors" in preferences. I am now leaning towards a standard RGB monitor for color/animation and using the zenith for text processing (in fact, both can be running at the same time!). ---------------------------------------------------------------------------- Gregg Whitcomb USENET: ucbvax!ic!whitcomb ARPA: whitcomb@ic.berkeley.edu ----------------------------------------------------------------------------
dclemans@mntgfx.MENTOR.COM (Dave Clemans) (10/07/87)
Re: discussions about smearing and flickering... Long persistence monitors are not necessarily a cure-all to interlace flicker; it all depends on the individual. Different people are more or less sensitive to flicker; different people are more or less sensitive to video smearing. dgc
richard@gryphon.CTS.COM (Richard Sexton) (10/08/87)
In article <177@tahoma.ARPA> bakken@tahoma.ARPA (Dave Bakken) writes: > >Another A2000 question: Is smearing a problem with a long-persistence >monitor on the Amiga (both with the stock Amiga and with a 68020/68881 board)? >Would it be noticable only with the fastest of animations, or most/all >animations and even routine operations with a WYSISYG word processor or a >paint program? Yes, smearing will be a problem with long persistence monitors, but if you have a 68020/68881 it will run so fast that smearing wont be a problem. Ok, ok, real answer: Yes, smearing is going to be a problem. The worst problem is where you have an illuminated area on the screen that is black in the next frame. It wont be as bad if a white area turns into a yellow area. Yes, it will even be a problem for word processors, but one workaround is to use black text on a light background. This smears less when you scroll. Why do you think Xerox machines and Macs have a black on white display ? The real answer is SCAN DOUBLERS. Consider: if somebody (anybody) brings out a LP monitor, it wont flicker, but it will smear, and you probably arn't going to be too pleased with the colors. But if you have a scan doubler, you can use any (compatable) monitor that you like. >Dave Bakken >Boeing Airplane Commercial Company -- Richard J. Sexton INTERNET: richard@gryphon.CTS.COM UUCP: {hplabs!hp-sdd, sdcsvax, ihnp4, nosc}!crash!gryphon!richard "It's too dark to put the keys in my ignition..."
cjp@vax135.UUCP (Charles Poirier) (10/08/87)
All this talk about long-persistence monitors leads me to wonder. Does anybody have some quantitative knowledge of the time constants involved? What is the 1/e decay time of "short" vs "long" persistance phosphors? I'm mainly interested in color monitor phosphors, I don't care to know about 15 second green monochrome. And what is needed to kill most of worst-case perceptible flicker? My uneducated guess is maybe .05 to .1 second. What I'm getting at is this: Is it *possible* to have a "medium" persistance monitor that neither flickers much nor smears much? -- Charles Poirier (decvax,ucbvax,ihnp4,attmail)!vax135!cjp "Docking complete... Docking complete... Docking complete..."
schwager@uiucdcsm.cs.uiuc.edu (10/08/87)
> ...deletions... > (Or you want a frame buffer the deinterlaces the video for you.). > > --Chuck McManis > uucp: {anywhere}!sun!cmcmanis BIX: cmcmanis ARPAnet: cmcmanis@sun.com Where do I get one? -mike schwager -- {ihnp4,convex,pur-ee}!uiucdcs!schwager schwager%uiuc@csnet-relay.arpa University of Illinois, Dept. of Computer Science
peter@dalcsug.UUCP (10/10/87)
In article <7200014@uiucdcsm> schwager@uiucdcsm.cs.uiuc.edu writes: > >> ...deletions... >> (Or you want a frame buffer the deinterlaces the video for you.). >> >> --Chuck McManis >> uucp: {anywhere}!sun!cmcmanis BIX: cmcmanis ARPAnet: cmcmanis@sun.com > >Where do I get one? Did I hear a rumour that they were to be shown at AmiExpo? Can anyone from NY City (that attended AmiExpo) comment on this? How much would a monitor that could handle the increased scan frequency cost? It wouldn't matter much to me if the scan doubler was cheap and I couldn't afford the new monitor! >-mike schwager >-- {ihnp4,convex,pur-ee}!uiucdcs!schwager schwager%uiuc@csnet-relay.arpa > University of Illinois, Dept. of Computer Science Peter Philp Dalhousie University, Halifax, Nova Scotia peter@dalcsug.uucp
keithd@cadovax.UUCP (Keith Doyle) (10/13/87)
In article <1767@dino.cpe.ulowell.edu> miner@dino.cpe.ulowell.edu (Rich Miner) writes: >Smear vs Flicker? I say purchase a multi-sync monitor and wait a few months. But for those of you who bought your Amiga to do desktop video, the answer is not scan-doublers, or LP monitors, as they won't help when you videotape the output and run it on someone's TV. For those people, the real answer is: Learn to Design Hi-Res Screens that Don't Flicker. How much are you bothered by flicker of images while watching TV? Well guess what guys, the Amiga is running at the exact same rate and interlace as that. Using a LP monitor or scan doubler at home is likely to mislead you into thinking your designs are not flickering, and as soon as you give a videotape to a friend he'll come back and tell you it looks like shit. I want to stick with standard persistance monitors because I want to know what my output is going to REALLY look like (well, closer anyway) when transferred to tape. Keith Doyle # {ucbvax,decvax}!trwrb!cadovax!keithd Contel Business Systems 213-323-8170
richard@gryphon.CTS.COM (Richard Sexton) (10/14/87)
In article <1792@cadovax.UUCP> keithd@cadovax.UUCP (Keith Doyle) writes: >In article <1767@dino.cpe.ulowell.edu> miner@dino.cpe.ulowell.edu (Rich Miner) writes: >>Smear vs Flicker? I say purchase a multi-sync monitor and wait a few months. > >But for those of you who bought your Amiga to do desktop video, the >answer is not scan-doublers, or LP monitors, as they won't help when >you videotape the output and run it on someone's TV. For those people, >the real answer is: Learn to Design Hi-Res Screens that Don't Flicker. > >Keith Doyle Keith has a good point. The worst offenders for flickering are 1) Horizontal lines, especially lines of 1 pixel thickness. These are nasty because in an interlaced screen the line is only displayed in one of two frames, kind of "now you see it, now you dont". I syspect this is the reason the top border of Intuition windows went from single pixel lines to thicker lines from 1.1 to 1.2. Lines of more than one pixel arn't as bad. 2) Colours - Flicker is also dependent on the colors used. A color scheme where there is high contrast bewteen the two colors is going to flicker worse than a scheme where the colors are closer together in contrast. For example, a worst case flicker pattern has to be a bunch of single pixel white lines against a black background. (In {320 || 640} x 400 mode) Note that its only the CONTRAST that counts, not the COLOR value. For example cyan and beige are very different in hue, but quite close in (?) luminous output, and this combination (and others) does'nt seem to flicker much. "Hope this helps" -- Richard J. Sexton INTERNET: richard@gryphon.CTS.COM UUCP: {hplabs!hp-sdd, sdcsvax, ihnp4, nosc}!crash!gryphon!richard "It's too dark to put the keys in my ignition..."
haitex@pnet01.CTS.COM (Wade Bickel) (10/14/87)
Would anyone be intrested in a monitor which provides flicker
free interlace display without LP monitor problems (ie: smearing)?
I am currently investigating the possibilities of bringing such
a monitor to market (though it is just an unlikely possibility at
this point. Anyone out their in position to build monitors? If
so send me some E-Mail!
Wade.
^ should be a "," , I've got a tempermental
connect.
UUCP: {cbosgd, hplabs!hp-sdd, sdcsvax, nosc}!crash!pnet01!haitex
ARPA: crash!pnet01!haitex@nosc.mil
INET: haitex@pnet01.CTS.COMkim@amdahl.amdahl.com (Kim DeVaughn) (10/17/87)
In article <1894@gryphon.CTS.COM>, richard@gryphon.CTS.COM (Richard Sexton) writes: > > Note that its only the CONTRAST that counts, not the COLOR value. For example > cyan and beige are very different in hue, but quite close in (?) luminous > output, and this combination (and others) does'nt seem to flicker much. Actually, the color does matter somewhat, as the eye's sensitivity to, and visually perceived persistence of different colors varies. As I recall, the sensitivity is greatest in the green, which also has the lowest visual persistence (I may have the color wrong). This can also vary from person to person. I've found that for myself, a medium steel gray, with just a slight pinkish cast background, and black letters gives me the least flicker for text-based applications like editors, terminal emulation, etc. Adding a greenish cast causes noticable flicker much sooner than does adding red or blue. /kim -- UUCP: kim@amdahl.amdahl.com or: {sun,decwrl,hplabs,pyramid,ihnp4,uunet,oliveb,cbosgd,ames}!amdahl!kim DDD: 408-746-8462 USPS: Amdahl Corp. M/S 249, 1250 E. Arques Av, Sunnyvale, CA 94086 CIS: 76535,25
richard@gryphon.CTS.COM (Richard Sexton) (10/18/87)
In article <16335@amdahl.amdahl.com> Kim DeVaughn writes: > >Actually, the color does matter somewhat, as the eye's sensitivity to, and >visually perceived persistence of different colors varies. As I recall, >the sensitivity is greatest in the green, which also has the lowest visual >persistence (I may have the color wrong). This can also vary from person >to person. I'm certainly not an expert on this subject, but I just can't see how 'eye persistence' has any bearing on the matter. Its the "now I'm here", "now I'm not" attribute of an interlaced display that causes the flicker, not the physiological response of the eye to color. >Adding a greenish cast >causes noticable flicker much sooner than does adding red or blue. This makes sense. The Green phosphor has a shorter persistence than either the Red or Blue. (Can't remember where I read this though) >/kim -- Richard J. Sexton INTERNET: richard@gryphon.CTS.COM UUCP: {hplabs!hp-sdd, sdcsvax, ihnp4, nosc}!crash!gryphon!richard "It's too dark to put the keys in my ignition..."
grr@cbmvax.UUCP (George Robbins) (10/19/87)
In article <177@tahoma.ARPA> bakken@tahoma.ARPA (Dave Bakken) writes: > > Another A2000 question: Is smearing a problem with a long-persistence > monitor on the Amiga (both with the stock Amiga and with a 68020/68881 board)? > Would it be noticable only with the fastest of animations, or most/all > animations and even routine operations with a WYSISYG word processor or a > paint program? I would expect some smearing effect with a long persistence monitor. Whether this would be a problem with animation would lie in the eyes of the beholder. Most of the complaints about smearing relate to the udesirable effects such as trails when scrolling or moving text data. In the case of animations, the effect might well be positive. In any case, you might note that the long- persistence color phosphers aren't really that long as compared to say an IBM PC monochrome monitor. Ambient illumination also has an effect, in normal lighting you might see no smearing, in darkness everything might display ghostly green trails. -- George Robbins - now working for, uucp: {ihnp4|rutgers|allegra}!cbmvax!grr but no way officially representing arpa: out to lunch... Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
grr@cbmvax.UUCP (George Robbins) (10/19/87)
In article <1926@ucbcad.berkeley.edu> whitcomb@ic.UUCP (Gregg Whitcomb) writes: > > I just received my B2000 (It's hard to believe after all the waiting). > Since I couldn't decide on a monitor when I ordered it, I decided to use > an old <$100 zenith monochrome (amber) monitor which has been sitting idle for > two years. I was VERY impressed with the quality of the picture the 2000 > produces with it! (Great job GR and C= !). I was also able to reduce > flicker almost entirely by adjusting the "colors" in preferences. I am > now leaning towards a standard RGB monitor for color/animation and using > the zenith for text processing (in fact, both can be running at the same > time!). Well, that was the idea for having the monochrome composite output, with full grey scale. It lets anybody attach a low-cost monitor for text or graphics activity. I don't know if it was a great trade-off relative to having built-in color composite, but when we were working on the A500, there was strong emphasis on "productivity" applications and the feeling that Amiga video capabilities were "too good" to survive the effects of an RF modulator or color composite monitor. All the ballyhoo about "desktop video" didn't come along until later. The key item is that the monitor have "composite monochrome" input *NOT* "IBM TTL" and should have a long persistence Amber or Green phospher. I've used amber displays made by Amdek and Magnavox/ Phillips. (Warning: I've seen some with short persistence green phosphers). Check the "Computer Shopper" or similar publications for advertisments. I would appreciate hearing of any other brands/models that work well. -- George Robbins - now working for, uucp: {ihnp4|rutgers|allegra}!cbmvax!grr but no way officially representing arpa: out to lunch... Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
grr@cbmvax.UUCP (George Robbins) (10/19/87)
In article <1950@gryphon.CTS.COM> richard@gryphon.CTS.COM (Richard Sexton) writes: > In article <16335@amdahl.amdahl.com> Kim DeVaughn writes: > > > >Actually, the color does matter somewhat, as the eye's sensitivity to, and > >visually perceived persistence of different colors varies. As I recall, > >the sensitivity is greatest in the green, which also has the lowest visual > >persistence (I may have the color wrong). This can also vary from person > >to person. > > I'm certainly not an expert on this subject, but I just can't see how > 'eye persistence' has any bearing on the matter. Its the "now I'm > here", "now I'm not" attribute of an interlaced display that causes > the flicker, not the physiological response of the eye to color. > > >Adding a greenish cast > >causes noticable flicker much sooner than does adding red or blue. > > This makes sense. The Green phosphor has a shorter persistence than > either the Red or Blue. Sorry, typically green has the longest persistance of the color phosphor triads. I suspect that this is due to unpleasantly short peristance of the red and blue phosphers, rather than any intentional characteristic of the green phospher. If I remember correctly, high speed oscilloscopes use a blue phospher for photograpy, while radar screens and other long ultra-long persistance display use this ugly yellow-green stuff. -- George Robbins - now working for, uucp: {ihnp4|rutgers|allegra}!cbmvax!grr but no way officially representing arpa: out to lunch... Commodore, Engineering Department fone: 215-431-9255 (only by mo! unioun
charles@hpcvcd.HP (Charles Brown) (10/24/87)
> I'm certainly not an expert on this subject, but I just can't see how > 'eye persistence' has any bearing on the matter. Its the "now I'm > here", "now I'm not" attribute of an interlaced display that causes > the flicker, not the physiological response of the eye to color. > Richard J. Sexton This is clearly not correct. If it were true, then all people would perceive flicker the same. I see outrageous flicker where some people see none. I see ficker on televisions with ordinary shows, and on movie theatre screens. I see some flicker on my Sony monitor using my A1000 without interlace. All of this is quite uncomfortable. Charles (its in the eyes) Brown
tomb@hplsla.HP.COM (Tom Bruhns) (10/27/87)
Writes / richard@gryphon.CTS.COM (Richard Sexton) /: > > I'm certainly not an expert on this subject, but I just can't see how > 'eye persistence' has any bearing on the matter. Its the "now I'm > here", "now I'm not" attribute of an interlaced display that causes > the flicker, not the physiological response of the eye to color. If you have any doubts that there is indeed a physiological/psychological aspect to all this, try viewing exactly the same display (interlaced) with low and moderate ambient lighting and low and moderate monitor intensity to match. MOST people (:-) perceive the low light/low intensity situation as having much less flicker. I know for a fact this works on standard B/W TV's, as well as on color monitors, and the B/W phosphor has a time constant of not-very-many microseconds (which allows light pens and flying spot scanners to work). I still wanna measure my monitors' phosphors' persistances, but haven't found time yet. Will post when I do. (The above experiment can also be done with a single LED, driven by a short pulse every 1/30 second or so -- same results, I believe -- and the LED turns off pronto when you turn off the drive current.) Tom Bruhns uucp: !hplabs!hplsla!tomb
king@dciem.UUCP (Stephen King) (10/27/87)
In article <4410012@hpcvcd.HP> charles@hpcvcd.HP (Charles Brown) writes: >perceive flicker the same. I see outrageous flicker where some people >see none. I see ficker on televisions with ordinary shows, and on >movie theatre screens. I see some flicker on my Sony monitor using my >A1000 without interlace. All of this is quite uncomfortable. > Charles (its in the eyes) Brown Agreed. The correct term is Persistence Of Vision. My supervisor is a perceptual psychologist and could give you a detailed account of the phenomenon, but he's not here right now. I also see flicker on my Sony/ Amiga in non-interlaced mode, but only when I'm not looking directly at the screen. The most sensitive part of the eye is the fovea, a small patch at the center of the retina. This area is most sensitive to color, and exhibits the highest persistence. Images cast outside of the fovea are much more susceptible to flicker. Reducing the screen brightness will also reduce the apparent flicker. Reduce the room brightness to taste. Don't laugh, I have visited many graphics houses where the presentation rooms were quite dark, except for the display screen, and this was with 60Hz non-interlaced LP monitors, because they tend to wash out in bright light. I have tried the Amiga in interlaced mode on Conrac and Mitsubishi LP monitors, but found the colors rather weak and the contrast low, although there was no noticeable smear in fast moving scenes. Again, the smear depends on the color of the background. On a black background, smear is sometimes visible as a faint green after-image, but I did not find it objectionable. I can provide references if anyone wishes more info. ...sjk -- * Defence & Civil Institute * ...!utzoo!dciem!king * of Environmental Medicine * Stephen J King - Simulation & Training Group - (416) 635-2149