Crt effects list

RetroArch Additions Shaders
#13

Yes, the bright image creates radiation that is reflected in the glass and produces that glowing effect, which is more noticeable in high contrasts.

If it doesn’t have that glass, then it doesn’t produce that effect, but I wouldn’t bet my life on it. There may be CRTs without glass that have that effect. Perhaps the anti-static glass (I said magnetic before, lol) is very far from the tube and produces it, or maybe the tube is of such poor quality that it spreads internally.

Those parameters should be separate, to adapt to other CRTs or ambient lighting; the darker the room, the more noticeable it is.

The glow effect of CRTs can be seen with bezel shaders.

PS: An interesting fact: when the glass is flat, if you look at the CRT from an angle, the glare is shifted by the separation, and you can see the soft reflection of the image, as if repeated.

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#14

There is another effect that affects monochrome monitors: if it is green, the screen turns green, just like the other colors. I don’t know what this is called.

image

#15

maybe the type of phosphor? https://en.wikipedia.org/wiki/Phosphor#Standard_phosphor_types

#16

This is because the phosphors are all green. On a color CRT the background noise creates dark gray and normally you can only see it when you set the brightness too high.

Halation is visible on cameras because cameras have a glass lens. On a normal CRT it should not be visible. When there is a second glass panel, there still shouldn’t be a halation effect because the glass is flat. However, smudges, oil, and dirt on the second glass panel can create a sort of micro-curvature that will create halation (this why dirty glass looks cloudy). If the panel is acrylic instead, it will accumulate scartches and also become cloudy. I believe some arcade cabinets used acrylic panels as a safety measure.

#17

11 (de)convergence and defocus that increase near screen edges

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#18

uhm… warmup time?

My old cab has less contrast and smaller image at power-on time; needs a minute to fully reach intended “levels”

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#19

I remember it was visible, maybe not as obvious as how seen in cameras

BTW, it also did reflected to phosphor strips https://forums.libretro.com/uploads/default/original/3X/7/5/75fb1ce2b99acdd719a4118fd4bee938e0b71428.jpeg

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#20

Yeah, a little bit visible. Very subtle. Also depends how dirty the screen is :slight_smile:

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#21

Halo doesn’t exist on a real CRT, that’s a camera effect. Afterglow and glow do exist, glow in small amounts.

In fact many shaders try to imitate a photo screenshot of a CRT and won’t look at all like a real crt e.g. new-pixie. That’s mostly like a magazine photo of a CRT, exaggerating all effects and introducing others that don’t really exist like scalines rolling here and there. Looks pleasant and neat nevertheless, if not a bit heavy.

A real CRT looks mostly like crt-lottes, Another two-three shaders i wrote (promotion time) that look close to a real CRT are cyclon, gdv mini ultra Trinitron (parts of Guest.r code here), crt-pocket SLANG. I mean those were actually compared and developed alongside my 2 CRTs, 14" Trinitron and 20" slot mask.

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#23

Couldn’t large halos be the effect of those cabs coming with a second glass? I mean, not the crt itself.

#24

It could have some reflection i guess.

#25

That’s for sure, but maybe If the second glass is not perfect, it could scatter or partially reflect light within its surface.

#26

who knows, it could even reflect environment light and more.

#27

I also said this before

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#28

In my experience, glow on a CRT is not just a camera effect. As other people in this thread have suggested, it might be related to a dirty screen or some age/wear-related problems. Maybe a black matrix, microfilter, etc. might have an effect.

Or maybe I’m hallucinating this. Lol

On my 1985 and 1989 CRTs which have gray screens instead of deep black ones whenever powered off, they still have a bit of a gray afterglow even after powered off, showing a blurry afterimage of whatever was on-screen. When I turn the lights off in my room, the screen is still emitting (or reflecting?) a tiny, faint amount of light. This entire effect probably isn’t significant enough to consider emulating, but it’s worth thinking about in this discussion.

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#29

If it has to do with phosphorus but doesn’t mention the name of the effect, someone mentioned the name in a Vogon forum, but I can’t find it.

Saturated colors in digital cameras overwhelm the CMOS sensor, producing a ‘defect’ known as Blooming.

The halo of CRTs is somewhat different. Even though it is completely transparent, it always causes refraction, but in this case, they are not; they have a thin film. I suppose the reasons are: to appear flat, anti-static, and to darken the image (making blacks blacker).

In a well-lit environment, a monitor with gamma 1.8 cannot be perceived, but with the light off and a black background image, it is blatantly obvious. What’s more, if you look closely at the image, you can see the silhouette reflected in the glass.

This is not a memory, it is suffering; calibrating these monitors was painful.

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#30

This is caused by the thermal contributor to phosphor decay (phosphor decay has three components), and I purposefully stop it from happening by forcing my phosphor shader to go down to 0. Otherwise it gets stuck due to a lack of floating-point precision.

There was a very good IEEE paper about the security issues of thermal after-images.

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#31

I don’t know who will agree with me, but in my opinion, many CRT effects (and even analog video effects in general) add a dynamic and lifelike (teeming with life) quality to games. Perhaps we used to dislike these effects, characteristics, or even limitations, but today we appreciate their value after losing them in the age of digitization and ideal screens

I know I am not alone who felt this way, there are others

also I noted many younger peoples use effects that make their videos (in youtube or whatever) get analog artifacts or crt effects (especially scanlines or curves, and sometimes even masks) or even film artifacts although they did not live through those times, so this is not just a nostalgia

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Koko-aio shader discussions and updates
#32

about Convergence adjusting in flyback

I remember it was in SONY only, in other TVs it was Focus, or I am wrong?

anyway I kinda like a bit of misconvergence in shaders, it kinda give nice effect, also I think you can’t get 100% convergence in real CRT, at least there will be some differences around the screen areas

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#33

Something I just remembered:

  • Partly filtered YPbPr (allegedly Sony 2000s would filter Pb/Pr but not Y)
  • Filtered YPbPr (Panasonic CT-36D30B, appears to do Y trap filter and slight C lowpass)
  • YPbPr with a delay line, causing Y to be out ot sync from Pb/Pr (Toshiba/Orion)
  • Filtered Y in S-Video (Panasonic again)
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