3 ms·

The TTL RGBI 320x200 one looks pretty accurate to me when compared to a real 15.7khz 200-line CRT, and the render of Crystal Caves on a double-scanned VGA also

The TTL RGBI 320x200 one looks pretty accurate to me when compared to a real 15.7khz 200-line CRT, and the render of Crystal Caves on a double-scanned VGA also looks about right as compared to an early 90's 14" VGA CRT. Can't comment on the others, though. In Part 2 (monochrome) the Apple II green monochrome is spot-on accurate and the Amber MDA 80x25 textmode is pretty good except that the background contrast is quite poor. A real amber MDA monitor has much deeper blacks.

cmiller1 6y ago
The contrast issue is what I notice the most. CRTs had much more "glow" and "bleed" I guess
- kiwidrew 6y ago
  Many of the retro takes on CRTs seem to over-emphasize the scanlines and (perhaps in pursuit of capturing the CRT "glow") also end up over-doing the background. On a properly adjusted CRT you shouldn't be able to see any scanlines at all in areas that are displaying pure black, unless you're viewing the display in an extremely dark room.
  - cmiller1 6y ago
    Yeah I don't see the scanlines at all on the CRT I've been using
    - viler 6y ago
      (Author of the script here): appreciate the observations. Pretty much all of these parameters (scanline intensity/sharpness, pixel blur, glow/halation, blackpoint for the background) can be adjusted to taste in the configuration files. :) I tried to show the range of possibilities in the screenshots/video samples, e.g. higher-res EGA/VGA with no visible scanlines, and some amber monitor shots with deeper blacks, etc. Admittedly, this script is geared more towards simulating lower-resolution CRTs - mostly because my approach entails a large oversampling of the input.
      - kiwidrew 6y ago
        I'm impressed with the results from your lo-tech batch file approach. The output is really quite nice. It turns out that real CRTs also have a number of user-adjustable parameters, which of course makes it impossible to define any sort of "canonical" or most-accurate preset. :) (Like this weird paper-white monochrome CRT that uses P7 phosphor, designed for 350-line MDA but can also handle a greyscale 15.7khz 200-line CGA input... the scanlines are so sharp that it looks 100% fake!)
        viler 6y ago
        Yup, multisync/multi-scan sure complicates things. :) I'd still like to give it enough flexibility so that a preset can at least be accurate to a particular mode of operation. I actually went down the rabbit hole of looking up a precise persistence curve for the P39 phosphor (as used in the IBM 5151) - found conflicting data, but a friend will be helping out with a video and an ad-hoc program to get some results, so we'll see!

cmiller1 6y ago

The contrast issue is what I notice the most. CRTs had much more "glow" and "bleed" I guess

kiwidrew 6y ago
Many of the retro takes on CRTs seem to over-emphasize the scanlines and (perhaps in pursuit of capturing the CRT "glow") also end up over-doing the background. On a properly adjusted CRT you shouldn't be able to see any scanlines at all in areas that are displaying pure black, unless you're viewing the display in an extremely dark room.
- cmiller1 6y ago
  Yeah I don't see the scanlines at all on the CRT I've been using
  - viler 6y ago
    (Author of the script here): appreciate the observations. Pretty much all of these parameters (scanline intensity/sharpness, pixel blur, glow/halation, blackpoint for the background) can be adjusted to taste in the configuration files. :) I tried to show the range of possibilities in the screenshots/video samples, e.g. higher-res EGA/VGA with no visible scanlines, and some amber monitor shots with deeper blacks, etc. Admittedly, this script is geared more towards simulating lower-resolution CRTs - mostly because my approach entails a large oversampling of the input.
    - kiwidrew 6y ago
      I'm impressed with the results from your lo-tech batch file approach. The output is really quite nice. It turns out that real CRTs also have a number of user-adjustable parameters, which of course makes it impossible to define any sort of "canonical" or most-accurate preset. :) (Like this weird paper-white monochrome CRT that uses P7 phosphor, designed for 350-line MDA but can also handle a greyscale 15.7khz 200-line CGA input... the scanlines are so sharp that it looks 100% fake!)
      - viler 6y ago
        Yup, multisync/multi-scan sure complicates things. :) I'd still like to give it enough flexibility so that a preset can at least be accurate to a particular mode of operation. I actually went down the rabbit hole of looking up a precise persistence curve for the P39 phosphor (as used in the IBM 5151) - found conflicting data, but a friend will be helping out with a video and an ad-hoc program to get some results, so we'll see!