87

I was working in software development at the time, and this wasn't seen as a problem. Colour monitors were expensive and not usually high-quality. In PC-compatibles, the Colour Graphics Adapter (640x200) wasn't regarded as adequate to be the only display on a machine; the Enhanced Graphics Adapter (640x350) appeared the same year as the original Mac, but ...


39

The Mac was designed from the start to be a GUI-based machine so clear, high-resolution graphics were a requirement. At the same time available memory was extremely limited due to cost considerations. The original Macintosh only had 128kB of RAM of which over 21kB were used by the display. Going to even 8-bit color at that resolution would have pushed the ...


31

CRT TVs are analog devices, there is no "pixel", but the size of the spot limits the resolution of the image, as the size of silver nitrate crystals limits the resolution of photo films. Several arrangements of the colour stripes on the CRT tubes have been designed, they are a compromise between resolution, luminosity and the precise alignment of the ...


29

I imagine it being a huge downgrade for some, not to have color on the Macintosh. Macintosh games were black and white in the beginning, while Apple II had color. For back then the whole assumption of a 512x342 pixel B&W display being a downgrade from a display with an effective (*1) colour resolution of 140x192 is so strange(*2), I doubt anyone would ...


28

What you're missing is that early computers didn't generate their video signals the way that modern computers do. You're probably picturing a C64 working in much the same way that a VGA adapter does: you specify a color index to RGB mapping, and a digital-to-analog converter looks up that mapping and generates appropriate red, green, and blue signal values. ...


21

What's the reason for the limited palette size? Intuitively it would seem straightforward to e.g. have a palette of 65536 colors; it would just be a matter of having a few 16-bit registers in the video chip, easy enough even given the technology of the day. The resolution of the digital to analog conversion circuitry would need to be improved, but ...


18

S-Video relies on colour transformation from RGB to YUV, and then takes the U and V and modulates them using a colour subcarrier. The TV has to undo all these steps in order to get the original RGB signal. If the subcarrier frequency is not in phase with the pixel clock (as will be the case if using different crystals), then moving artifacts will show up in ...


15

My guess is that your VGA monitor is reporting itself as a mono monitor to the VGA card. This may be caused by the monitor being too modern for your Compaq: The VGA card expects the monitor to report its capabilities using three pins from the VGA connector, but modern monitors use I2C to report EDID information on those pins. If the impedance at some of ...


14

I think you're conflating a few issues: being in-phase with the colour subcarrier; being sampled at a rate less than or equal to the colour subcarrier; and being sampled at an integer division of the colour subcarrier. Being in-phase has exactly one effect: the artefacts on horizontal edges are consistent from one line to the next. The edges do not ...


14

The email from Bob Yannes which you linked to gives the answer: I'm afraid that not nearly as much effort went into the color selection as you think. Since we had total control over hue, saturation and luminance, we picked colors that we liked. In order to save space on the chip, though, many of the colors were simply the opposite side of the color wheel ...


14

I believe the assumptions of the question are wrong. We did not buy the Mac to play games, it was more or less strictly a business machine. Main usage in the beginning around me was creation of printed material including illustrations. Slightly later the laser printer came along making it possible to create camera ready material inhouse. Of course, I could ...


11

The pixel clock has to be fast enough to generate the number of pixels you want to display horizontally within the 56 microsecond scan line interval. At 3.58MHz, you only get about 200 pixels. This was fine for the Atari 2600 et al, which had 160 horizontal pixels, but the other systems you mentioned had higher horizontal resolution, so had to use a faster ...


11

First, the Commodore 64 could do better than 320x200 in monochrome. Without any special tricks, it could display two colors per 8x8 cell at that resolution. One reason of the limited color palette comes down to how much logic you could cram into one chip. Take the Atari 800. It was able to produce roughly 128 colors (later, 256) but it actually had TWO ...


11

I personally agree with all of the answers that say something like “High quality bitmapped monochrome displays beat low quality PC color/character graphics.” E.g. for things like preparing documents for publication - affordable high quality printers were pretty much only monochrome. Why prepare a document that displays colors that cannot be printed? Except....


10

The pixel clock doesn't have to be the same as the color clock. In fact, it's usually higher. Remember that in a composite video signal, the chrominance information (whose resolution depends upon the color clock) is less important than the luminance information (whose resolution depends upon the pixel clock), so the color clock can be (and usually is) slower ...


10

As for why did the Apple II have color and the new Macintosh didn't? Because color wasn't as important as resolution: "Steve Jobs asserted last January [1985] that no color Mac would surface for a few years at least, until such time as a color equivalent of the LaserWriter was feasible. He contended that color wasn't that important and said the Mac ...


9

It depends on whether the TV is color or black-and-white/monochrome. Older B&W TVs (and ordinary TV electronics and tubes converted into monochrome monitors by some el-cheapo monitor vendors), did not block (filter out) color burst frequencies (with the associated IQ bandwidth), and the cheap analog filtering did gracefully degrade as the bandwidth was ...


9

CGA (1981) monitors have digital TTL RGBI inputs (red, green, blue, and intensity), giving you a fixed palette of 16 (24) colors: ## | I R G B | Color ---+---------+-------------- 0 | 0 0 0 0 | black 1 | 0 0 0 1 | blue 2 | 0 0 1 0 | green 3 | 0 0 1 1 | cyan 4 | 0 1 0 0 | red 5 | 0 1 0 1 | magenta 6 | 0 1 1 0 | yellow 7 | 0 1 1 1 | light gray 8 | 1 ...


9

The Wiki Entry says that the N64 calculated with 24-bit color, but output 21-bit. Right,that's the way it is. The 15 or 24 Bit colour is what the Reality Display Processor can produce (see Video Interface on p.46). Internally it works with a 32 Bit RGBA based pipeline. Results are stored as 15 or 24 Bit values before being send to the DAC. This is where ...


9

With all these 'or' in between and jumping between various points, requirements and conclusions, it's a bit unclear what your're looking for. If this is about most colour with least memory, then the (unofficial) modes Mode 8 and Mode 13 are your thing. Or was it a limitation of bandwidth with the 6845 chip that couldn't handle both 320 horizontal pixels ...


9

The Apple IIgs Hardware reference explains it: In 640-pixel mode, color selection is more complicated. The 640 pixels in each horizontal line occupy 160 adjacent bytes of memory, each byte representing 4 pixels that appear side-by-side on the screen. The 16 colors in the palette are divided into four groups of 4 colors each. The first pixel in each ...


9

I was a VAX mainframe sysadmin when I bought my first Mac in 1985. At the time we had Apple II computers for some purposes as well as assorted Digital terminals some expensive ones of which had colour, with ASCII and some primitive block character graphics. The Fat Mac was amazing with its small screen showing beautiful high-resolution black and white ...


8

Short Answer: There is no relation. What seems like a relaiton is non related coincidence. Long Answer: First of all, there is no colour clock. The mentioned frequency of 3.58 MHz is not a colour clock, but the carrier frequency used to modulate the encoded colour signal atop the basic B&W signal. There is no relation to RAM speed, pixel generation ...


8

Caveat: 'Why Not' questions are like 'What If' and rarely have a definite answer. It's an (educated) speculation at best. In case of interface and connectors, NIH (Not Invented Here) is a big issue. Beside the fact that adding more interfaces costs money, manufacturers usually love to have closed systems where they control - and most important sell all ...


7

The GBS8220 seems to be the standard way to use modern VGA monitors on old arcade machines. Do you know for sure if your Centipede machine outputs CGA/EGA (digital RGBI), or is it 15 kHz VGA (analog RGBHV)? Here is a list of flat panel monitors that support 15 kHz analog RGBHV signals. But they often come with caveats, such as you have to fiddle to get the ...


7

NTSC provides 227.5 colour cycles per line; PAL is very close to 283.75. In both cases, the visible area is around 80% of the line, but most home computers had a much bigger border than that — e.g. (of those I know offhand) the Acorn machines paint for 40µs, which is 62.5% of the line; the 48kb Spectrum paints for 128/224ths, which is around 57%; over in ...


7

The V9938 video chip in the MSX2 home computer can be programmed to disable the color burst but I don't know if any utilities or applications provided such an option to the user. That would have certainly been beneficial for the 80 column text mode and 2-color high resolution bitmap mode. Some MSX2 variants had a V9958 instead which has no composite video ...


7

Why aren't each pixel's bits stored sequentially on the SNES? Well, to start with, they are always (!) 8 pixels sequentially within a byte - and multiple byte in parallel for extended colour depth. Why? TL;DR: Because it simplifies hardware when multiple colour depth is handled. Why are graphics stored this way when, if each bit of a pixel was stored ...


7

I was playing around with an emulated Apple /// and while looking at the color demo I noticed that unlike the Apple ][, Not really, as the Apple II also didn't do red, just orange. Apple II colours were black, green, purple and white plus blue and orange when shifted (*1), the /// did not implement red as one of its supported colors. While in Apple II ...


6

I'm not sure if I understand the question correctly. TV composite is bandwidth limited because the color carrier signal blocks higher frequency. This means one particular type of signal cannot "gracefully degradate": If the horizontal resolution is too high, you'll just get colored jumble on the TV, and not somehow a fuzzy image in lower resolution. RF ...


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