Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!dali.cs.montana.edu!caen!sdd.hp.com!elroy.jpl.nasa.gov!ncar!noao!arizona!arizona.edu!ece.arizona.edu!dan From: dan@ece.arizona.edu (Dan Filiberti) Newsgroups: comp.sys.next Subject: Re: ColorStation questions Message-ID: <1991Apr24.231003@ece.arizona.edu> Date: 25 Apr 91 06:10:03 GMT References: <1991Apr24.082948.17763@cs.ucla.edu> <559@rosie.NeXT.COM> Reply-To: dan@ece.arizona.edu (Dan Filiberti) Distribution: usa,local Organization: University of Arizona Dept. of Electrical and Computer Engineering Lines: 47 Nntp-Posting-Host: dialsun.ece.arizona.edu >I am thinking about buying a color NextStation but I have been >somewhat alerted by some recent rumors about its capabilities. > It is known that the color NextStation can display 4096 colors > simultaneously using 4-bits per pixel for R,G, and B. Someone > thought this meant only 16 gray levels can be displayed ever ! Is > this true ? Yes, it is, of the 4096 different color values each pixel can take on, 16 of them are pure gray (Red == Green == Blue). However, PostScript employs dithering to display a lot more colors than can be represented by the device pixel values; thus a 256-gray image will look a lot better on the NeXTstation Color than on a non-dithered 16-bit display device. In many cases a 24-bit color image on the NeXTstation Color display is hard to distinguish from the same image on a 24-bit display. ------------------ This is just wonderful! Here, we thought we were getting a good price on a workstation, and 4096 simultaneous colors to boot. Now, we find that the price isn't the only thing that is cheap. Let's look at the bigger picture. NeXT claims that it can "display" 4096 colors on the screen at one time. What they don't tell you, is that you really have control over only 16 colors!. The rest are all permutations of the six that you pick! You know that is just lovely...once again research succumbs to the will of the masses. Our research deals with images of skin, which unfortunately, may contain over 256 shades of red, pink, various browns, greys, blues, and who knows what else. We are trying to determine which colors are important, and which aren't in the diagnosis of skin disorders. How can we do this on the NeXT ColorStation, everything is dithered, and most colors probably won't be represented. I guess this could be expected. After all, they didn't even allow for RGB input into the NextDimension board. I guess we can use these workstations to replace our video recorders, but not for research. I believe the following...if you aren't going to do it right, then don't do it at all.... Daniel Filiberti dan@helios.ece.arizona.edu [:)} ----------------- "One good flame deserves another, together they make fire." -----------------