5 ms·

A bit clickbait calling it "infinity contrast" even if it's higher contrast than an LCD, is it still a finite contrast. Probably not higher contrast than modern

A bit clickbait calling it "infinity contrast" even if it's higher contrast than an LCD, is it still a finite contrast. Probably not higher contrast than modern OLED TVs, but a clever hack with stuff at hand. Just not up to the hype of infinite.

nickthegreek 2y ago
Not sure I would call that clickbait when the Creator put that phrase in quotes in the original video title.
- smusamashah 2y ago
  FIY, current substitute title (using DeArrow chrome extension) is "DIY Rear-Projection TV - Recycling Broken TV And A Projector"
Kirby64 2y ago
The author is using a DLP projector to backlight the LCD. When the projector is displaying black it effectively is infinite contrast. The light is reflected away and never reaches the LCD to backlight it.
- smusamashah 2y ago
  Black color coming from projector isn't full black either https://www.projectorreviews.com/articles-guides/projector-black-levels-and-contrast/ https://www.projectorreviews.com/articles-guides/projector-b...
  - gibibit 2y ago
    Good point, I hadn't even thought of this.
  - mbreese 2y ago
    True, but for this purpose, it's "blacker" than a typical LED backlit TV. For a Youtube / DIY project ... I think the description is fine.
  - wdfx 2y ago
    He also did not do (or at least did not mention) anything about the reflected/diffused and ambient light behind and around the TV screen, which would negatively impact contrast.
    - 112233 2y ago
      Aw, give him a break. Neither do OLED tv reviews, but I do not see everyone piling on them "well, technically the contrast isn't inf because the screen is scattering the ambient light" Have you seen those samsung qdoleds? In a normally lit room they look more washed out than a VA panel, yet somehow still having an "inf" contrast...
  - mlyle 2y ago
    No. It's not literally infinite contrast. On the other hand, there's very little light spill from DLP--- and what little there is, is attenuated by a really big factor by the LCD. I'd guess the limiting factor is light scattered elsewhere in the room and by the front surface of the display.
- gibibit 2y ago
  Ignoring the fact that the projector doesn't get to true black (noted by smusamashah), and supposing there's no diffusion that spreads the light of a pixel out to surrounding areas of the display panel, it would be possible to say that the display has infinite contrast, I suppose that is true. Contrast is important, but alone it is useless. You could have a display with only two levels: black and white, and if the black is perfectly black, then it's infinite contrast (any level of white, no matter how dim, is infinitely brighter than total black), but 1-bit color would be useless in reality for home theater. To make infinite contrast useful, it's necessary to have HDR as well to take advantage of having very dark and very bright areas both able to be represented with detail. Plus having sufficiently bright maximum brightness so that the brightest highlights can really shine.
  - deepsun 2y ago
    Just to note that absolute black is not achievable. The best coatings in labs reach 99.99% but it's never 100%.
  - theshackleford 2y ago
    > To make infinite contrast useful, it's necessary to have HDR as well to take advantage of having very dark and very bright areas both able to be represented with detail. SDR benefits incredibly as well. HDR is another elevation. Getting stuck with LCD contrast for years was a travesty to image quality across the board.
- SirMaster 2y ago
  That's not true at all. Black on a projector is still projected light, especially with a DLP which have the worst contrast ratios of the 3 projector types (DLP, LCD, LCoS). What he is making here is a dual panel display. There are actually some LCD monitors that use this concept of 2 separate panel layers each providing their normal contrast resulting in a multiplicative effect. For the video posted here, the DLP is probably at best 1000:1 and the cheap old LCD is also maybe about 1000:1, so you get about 1 million:1 which is a lot, but not technically infinite like self-emissive display that can turn off the pixels completely for sections of the picture like OLED and microLED.
  - Dylan16807 2y ago
    What makes self-emissive "technically infinite" but not DLP? I would say the weak point of DLP is the screen material needing to be light-friendly, but that's on a sliding scale with the emissive display, not a hard line difference. Both of them preserve black levels when turning on, unlike traditional LCD, but also it isn't true black for either of them.
    - SirMaster 2y ago
      LCD projectors do better at contrast than DLP though. For example the Epson 5050UB or LS12000 do about 5000:1 native contrast. Most DLPs around the same price level are in the 1000:1 to at most 2000:1 contrast level. A DLP is nothing like an emissive display. The entire area of a projected image with any projector is always lit up by the light source. Any projector, including DLP is like a TV with a single backlight and no local array dimming. Here are some simple photos of DLP projectors and here you will clearly see that the black parts, like the black bars above and below the cinemascope image, or even the spill over past the edges of the panel are not black at all. https://i.redd.it/ak3lwsumvccc1.jpeg https://i.redd.it/ak3lwsumvccc1.jpeg https://preview.redd.it/eyc62402amnd1.jpg?width=4000&format=pjpg&auto=webp&s=a738a2adb4e1f96857b97fe0a9c6fb3cbedfff67 https://preview.redd.it/eyc62402amnd1.jpg?width=4000&format=... In that second photo, the odd shape of the black projected area is due to the user using keystone, so the image is not being displayed on that part of the imaging panel and it's just left black, but you can see then what the black level really is for projected "black" pixels.
- drjasonharrison 2y ago
  The projector lens's optics (coatings, materials, etc.) will have been designed and engineered to have a specified contrast ratio. So yes, if the internal light engine of the DLP truly reflected all light away, then, if it outputs zero photons for full-screen black, you could say the projector outputs zero photons. However, the DLP is not 100% effective; the interesting images will have a mix of bright and dark areas, and the lens and software image processing will raise the black levels above zero. Source: I worked at BrightSide Technologies before and after the acquisition by Dolby Laboratories and learned about DLP lens limitations from the engineer working on DLP+LCD based HDR displays.
smusamashah 2y ago
When I read infinity contrast, and knowing how great DIY perks is, I assumed it to be something like this https://youtu.be/JoLEIiza9Bc?t=335 https://youtu.be/JoLEIiza9Bc?t=335 but couldn't wrap my head around the idea on a TV.
numpad0 2y ago
the joke is that contrast is a ratio, and any number over zero* equals +inf. I've seen similar lines used in OLED advertisements during 2010s, despite many OLED having non-zero minimum intensity. It's a reference to those.
deleted 2y ago
[deleted]
Animats 2y ago
Projectors are only "infinity contrast" in total darkness. But with enough lamp power... Larry Ellison used to have a TV projector sized for a movie theater but aimed at a home sized screen, so he could watch movies and enjoy a view of the outside world at the same time. Of course, now anybody can go to Costco and buy a TV that bright.
- SirMaster 2y ago
  Projectors are never infinity contrast as they cannot turn off individual pixels. Projectors have a single constant light source to all pixels like a non local-array dimming TV. It's entirely up to the imaging panel to modulate the pixels, and none of the 3 panel types can block all the light for a pixel.
  - crazygringo 2y ago
    Laser beam scanning (LBS) projectors are, they genuinely don't beam any light to a black pixel. Unfortunately they don't really exist commercially anymore. I hope the technology develops and they come back... in a way, they are to constant light source projectors what OLED is to LCD. They seem like the obvious evolution.
    - SirMaster 2y ago
      Yeah, but I don't think anything like that has ever existed at actually usable brightness levels for a large home theater size screen, or at a resolution at least 1080p.
      - nkrebs13 2y ago
        He mentions at the end of the video that potentially multiple projectors could be used to increase brightness. Don't know anything about the tech -- just thought it was an interesting idea.
        Animats 2y ago
deleted 2y ago
[deleted]

nickthegreek 2y ago

Not sure I would call that clickbait when the Creator put that phrase in quotes in the original video title.

smusamashah 2y ago
FIY, current substitute title (using DeArrow chrome extension) is "DIY Rear-Projection TV - Recycling Broken TV And A Projector"

Kirby64 2y ago

The author is using a DLP projector to backlight the LCD. When the projector is displaying black it effectively is infinite contrast. The light is reflected away and never reaches the LCD to backlight it.

smusamashah 2y ago
Black color coming from projector isn't full black either https://www.projectorreviews.com/articles-guides/projector-black-levels-and-contrast/ https://www.projectorreviews.com/articles-guides/projector-b...
- gibibit 2y ago
  Good point, I hadn't even thought of this.
- mbreese 2y ago
  True, but for this purpose, it's "blacker" than a typical LED backlit TV. For a Youtube / DIY project ... I think the description is fine.
- wdfx 2y ago
  He also did not do (or at least did not mention) anything about the reflected/diffused and ambient light behind and around the TV screen, which would negatively impact contrast.
  - 112233 2y ago
    Aw, give him a break. Neither do OLED tv reviews, but I do not see everyone piling on them "well, technically the contrast isn't inf because the screen is scattering the ambient light" Have you seen those samsung qdoleds? In a normally lit room they look more washed out than a VA panel, yet somehow still having an "inf" contrast...
- mlyle 2y ago
  No. It's not literally infinite contrast. On the other hand, there's very little light spill from DLP--- and what little there is, is attenuated by a really big factor by the LCD. I'd guess the limiting factor is light scattered elsewhere in the room and by the front surface of the display.
gibibit 2y ago
Ignoring the fact that the projector doesn't get to true black (noted by smusamashah), and supposing there's no diffusion that spreads the light of a pixel out to surrounding areas of the display panel, it would be possible to say that the display has infinite contrast, I suppose that is true. Contrast is important, but alone it is useless. You could have a display with only two levels: black and white, and if the black is perfectly black, then it's infinite contrast (any level of white, no matter how dim, is infinitely brighter than total black), but 1-bit color would be useless in reality for home theater. To make infinite contrast useful, it's necessary to have HDR as well to take advantage of having very dark and very bright areas both able to be represented with detail. Plus having sufficiently bright maximum brightness so that the brightest highlights can really shine.
- deepsun 2y ago
  Just to note that absolute black is not achievable. The best coatings in labs reach 99.99% but it's never 100%.
- theshackleford 2y ago
  > To make infinite contrast useful, it's necessary to have HDR as well to take advantage of having very dark and very bright areas both able to be represented with detail. SDR benefits incredibly as well. HDR is another elevation. Getting stuck with LCD contrast for years was a travesty to image quality across the board.
SirMaster 2y ago
That's not true at all. Black on a projector is still projected light, especially with a DLP which have the worst contrast ratios of the 3 projector types (DLP, LCD, LCoS). What he is making here is a dual panel display. There are actually some LCD monitors that use this concept of 2 separate panel layers each providing their normal contrast resulting in a multiplicative effect. For the video posted here, the DLP is probably at best 1000:1 and the cheap old LCD is also maybe about 1000:1, so you get about 1 million:1 which is a lot, but not technically infinite like self-emissive display that can turn off the pixels completely for sections of the picture like OLED and microLED.
- Dylan16807 2y ago
  What makes self-emissive "technically infinite" but not DLP? I would say the weak point of DLP is the screen material needing to be light-friendly, but that's on a sliding scale with the emissive display, not a hard line difference. Both of them preserve black levels when turning on, unlike traditional LCD, but also it isn't true black for either of them.
  - SirMaster 2y ago
    LCD projectors do better at contrast than DLP though. For example the Epson 5050UB or LS12000 do about 5000:1 native contrast. Most DLPs around the same price level are in the 1000:1 to at most 2000:1 contrast level. A DLP is nothing like an emissive display. The entire area of a projected image with any projector is always lit up by the light source. Any projector, including DLP is like a TV with a single backlight and no local array dimming. Here are some simple photos of DLP projectors and here you will clearly see that the black parts, like the black bars above and below the cinemascope image, or even the spill over past the edges of the panel are not black at all. https://i.redd.it/ak3lwsumvccc1.jpeg https://i.redd.it/ak3lwsumvccc1.jpeg https://preview.redd.it/eyc62402amnd1.jpg?width=4000&format=pjpg&auto=webp&s=a738a2adb4e1f96857b97fe0a9c6fb3cbedfff67 https://preview.redd.it/eyc62402amnd1.jpg?width=4000&format=... In that second photo, the odd shape of the black projected area is due to the user using keystone, so the image is not being displayed on that part of the imaging panel and it's just left black, but you can see then what the black level really is for projected "black" pixels.
drjasonharrison 2y ago
The projector lens's optics (coatings, materials, etc.) will have been designed and engineered to have a specified contrast ratio. So yes, if the internal light engine of the DLP truly reflected all light away, then, if it outputs zero photons for full-screen black, you could say the projector outputs zero photons. However, the DLP is not 100% effective; the interesting images will have a mix of bright and dark areas, and the lens and software image processing will raise the black levels above zero. Source: I worked at BrightSide Technologies before and after the acquisition by Dolby Laboratories and learned about DLP lens limitations from the engineer working on DLP+LCD based HDR displays.

smusamashah 2y ago

When I read infinity contrast, and knowing how great DIY perks is, I assumed it to be something like this https://youtu.be/JoLEIiza9Bc?t=335 https://youtu.be/JoLEIiza9Bc?t=335 but couldn't wrap my head around the idea on a TV.

numpad0 2y ago

the joke is that contrast is a ratio, and any number over zero* equals +inf. I've seen similar lines used in OLED advertisements during 2010s, despite many OLED having non-zero minimum intensity. It's a reference to those.

deleted 2y ago

[deleted]

Animats 2y ago

Projectors are only "infinity contrast" in total darkness. But with enough lamp power... Larry Ellison used to have a TV projector sized for a movie theater but aimed at a home sized screen, so he could watch movies and enjoy a view of the outside world at the same time. Of course, now anybody can go to Costco and buy a TV that bright.

SirMaster 2y ago
Projectors are never infinity contrast as they cannot turn off individual pixels. Projectors have a single constant light source to all pixels like a non local-array dimming TV. It's entirely up to the imaging panel to modulate the pixels, and none of the 3 panel types can block all the light for a pixel.
- crazygringo 2y ago
  Laser beam scanning (LBS) projectors are, they genuinely don't beam any light to a black pixel. Unfortunately they don't really exist commercially anymore. I hope the technology develops and they come back... in a way, they are to constant light source projectors what OLED is to LCD. They seem like the obvious evolution.
  - SirMaster 2y ago
    Yeah, but I don't think anything like that has ever existed at actually usable brightness levels for a large home theater size screen, or at a resolution at least 1080p.
    - nkrebs13 2y ago
      He mentions at the end of the video that potentially multiple projectors could be used to increase brightness. Don't know anything about the tech -- just thought it was an interesting idea.
      - Animats 2y ago

deleted 2y ago

[deleted]