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in high APL scenes you will get better shadow rendition (e.g. in dark objects against a bright background)

Here's my understanding.

If you have a white field with a black box in the middle of the screen the black will be darker with a high ANSI DLP than with a CRT

Exactly what Kai said, in higher APL scenes, you will see more contrast on screen, therefore blacks will be blacker against whites.

What does that look like? To show shadow detail you're not seeing, all you need to do is turn up brightness. You'll see what shadow details you're missing, but you'll also lose highlights. How do you show ANSI CR details you're missing?

It's not a matter of missing details.

Exactly what Kai said, in higher APL scenes, you will see more contrast on screen, therefore blacks will be blacker against whites.

Isnt that an "aparent" blacks will be blacker because the whites are soooo bright they trick the eye to think black is black . If you put black velvet around that same center black field most likely you will now see that the black is not black but dark grey. Some people dont see it some can , mabey reio-ta is one of those people, same as those who see rainbow with dlp,s. At the local Hi FI shop i posed this question to the staff and they brought out a black piece of duvetine(splelling?) and put it up on the one side of the black box from a test disc they had and you could see that the side closer to the black cloth was more grey than the side next to the white field. So it really isnt blacker it just seems blacker.

Athanasios

Not so much do to with absolute Black.

It is more in mixed bright and dark areas of the same scene, the bright area will washout some details in the low light area of the image . Crt's weakness is in High APL scenes.

Bruce

ANSI CR measurement is difficult to perform and it is only good with that specific grid measurement.
It is only a reference and in is not really that acurate relative to every mixed frame where both drak and bright are there at the same time.

My Optoma has measured about 900:1. It is supposed to be almost eight times more than my CRT but again I just don't feel that it is there. More on this later. I also believe if they do the same mearuement with the same gid but 50/0 ire instead of 100/0 there would be different numbers for ANSI CR. It would be much closer to CRT, I would think.

ANSI CR is supposed to tell us how much of light scatter we get in a display system.
Another words how much white (top lumen) would contaminate the black portion in a single frame. Theoretically ANSI CR and ON/Off should be the same but it always lower than sequential due to lens, light paths and in case of CRT pj the phoshpor/faceplate and lens/barrel system that scatter the light . LC would reduce the amount of scatter.

My CRT looks lower in overall contrast (other than absolute black) than my Optoma.
Here is an hypothetical example that difference in ansi CR is not as great if your fixed panel is not a super bright one:
Assuming a fixed panel that is 12 ftl bright and 500:1 ansi cr, the darkest part of the image is .025 ft. Compare that to a CRT producing about 7 ftl on the same screen and assuming 120:1 ansi cr the black would be .058. Therefore the black would be elevated about two and half times the digital in mixed clips of 100 ire and 0 ire. That is 100 ire mixed with black. Keep in mind that our eyes are a lot less sensitive to black when there are brightness in given scene such as 100 ire.
While it is nice to have a hi ansi CR the effect is not as great as On/Off imo. That is exactly the opposite of what digital PJ's fans say which I disagree to some extent. And ANSI CR is not a replacement for On/off CR.

Isnt that an "aparent" blacks will be blacker because the whites are soooo bright they trick the eye to think black is black...So it really isnt blacker it just seems blacker.


Perhaps, but for the specific pattern used in the ANSI CR measurement, if the white levels are equilized, the black squares are in reality darker for digital vs CRT. This is something that can be measured and not just perception.

The relative importance of this metric to overall image quality is of course much harder to define. You may feel that high ANSI CR has no relation to image quality, but you can't argue that it's not real.

Perhaps, but for the specific pattern used in the ANSI CR measurement, if the white levels are equilized, the black squares are in reality darker for digital vs CRT. This is something that can be measured and not just perception.

The relative importance of this metric to overall image quality is of course much harder to define. You may feel that high ANSI CR has no relation to image quality, but you can't argue that it's not real.

"Originally Posted by nashou66
Isnt that an "aparent" blacks will be blacker because the whites are soooo bright they trick the eye to think black is black...So it really isnt blacker it just seems blacker."

I think the visual higher CR difference is due to higher measurements as well as our eyes that see the black actually blacker when there is a brighter part in the image.

it's not just perceptual.

In addition to reflections inside the lenses, there are reflections inside the CRT tubes that cause high APL scenes to wash out.

Kai

I thought I laid it out well!
In a perfect projector in the perfect room ansi and on/off CR should be the same.
Even with a digital projector of 1000:1 ansi CR and 5000:1 On/off CR the ansi is lowered by 4000:1 by various factors. Each element in a lens lowers the ansi. The barrel reflections lower the ansi. Internal reflection inside the light paths before light hits the lens lowers the ansi CR.

Contrast is number one for pleasing the eye hence torch displays in the stores but there is much more to a picture than contrast. Hence the death of CRT to the average consumer. It can't come close to the brightness of the other sets. Still waiting for another technology that gives me the film like quality of my CRT and also the depth and feeling like looking at real life. I forget I'm watching TV and become totally involved with the subject matter.

It's not a matter of missing details.

Actually it is. There are a few thing but a great example Darin Perrigo showed me when we were comparing my stack to my present projector more than a year ago now.

At the beginning of the film The Last Star Fighter there is a background of stars moving away all during the titles. When the white titles actually appeared on the screen, with the 3 chip they were there, when they came up on the stack the stars completely disappeared. Another example is the DTheater film Snow Falling on Cedars,a visually stunning film. In one scene the lead character is walking toward and then under a large dock. With the CRT there is nothing visible under that dock due to the nearly 50% split to the left of bright daylight. Objects of all sorts are clearly visible under that dock with the 3 chip. Although this is certainly a specific ,it dramatically illustrated what happens in demanding ANSI scenes.


Art
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What does that look like? To show shadow detail you're not seeing, all you need to do is turn up brightness. You'll see what shadow details you're missing, but you'll also lose highlights. How do you show ANSI CR details you're missing?

You can turn up the brightness all you want but if the shadow detail isn't there like on a CRT, it isn't there. When there were CRT rear projectors still in stores along with the digitals, no one was noticing the lack of shadow detail lost compared to CRT untill I pointed it out. It was obvious to me and still is.

Actually it is. There are a few thing but a great example Darin Perrigo showed me when we were comparing my stack to my present projector more than a year ago now.

At the beginning of the film The Last Star Fighter there is a background of stars moving away all during the titles. When the white titles actually appeared on the screen, with the 3 chip they were there, when they came up on the stack the stars completely disappeared. Another example is the DTheater film Snow Falling on Cedars,a visually stunning film. In one scene the lead character is walking toward and then under a large dock. With the CRT there is nothing visible under that dock due to the nearly 50% split to the left of bright daylight. Objects of all sorts are clearly visible under that dock with the 3 chip. Although this is certainly a specific ,it dramatically illustrated what happens in demanding ANSI scenes.


Art
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Did you have gamma boost in your stack?
Not that CRT doesn't have lower ansi and most often the detail in the black is lost/lowered due to more internal reflection than DLP.
Also if I recall correctly your stack was set up for max lumen and best black level. With CRT the higher the contrast setting actually you would get more washout in the black with itrascene.

With your 3-chip, are there scenes where details completely disappear but were present on your CRTs?


He stated the opposite

Art, are you saying you're getting better shadow detail out of a digital, and I mean in every scene that is displayed? How does "Sky captain and the World of tommorow" look? BTW I have a 73" Mitsubishi rear projector (73713, best one they ever made IMHO) I don't need to worry about brightness. I have't replaced my old front projector because nothing beats it- the RPTV in its/my price range. I really would have liked to see your stacked G90s to compare to my rear projection.

Thanks Art! That's exactly the response I was looking for.

With your 3-chip, are there scenes where details completely disappear but were present on your CRTs?

What needs to change to get both? Will a technology exist any time soon which can light a screen at ~8 foot lamberts like a CRT, while still seeing the darkest scenes like in Aliens and the details under the dock?

I think we will see something at CEDIA which will . Right now, even at 6000:1, my blacks are OK in low APL while having so many other great things. Thinks will only get better.

Art

He did? I thought he said there the stars on Last Starfighter and the details under the dock in Snow Falling on Cedars disappeared on his CRT but were present on his 3-chip.

He stated that due higher ansi (less washout) his black has more visible detail with his 3-chip DLP. But you said:

With your 3-chip, are there scenes where details completely disappear but were present on your CRTs?

reio-ta, you haven't even mentioned crushed whites. Just as big of a problem. My CRT doesn't crush whites across its entire contrast range and I can watch it in a very bright room, of course the shadow detail and black suffers a little because of the bright room.

I'll word it that way for the non-confusion of others.

To be frank you are flip flopping in your statements and seem to be confused yourself as you said it.

Shadow detail is not always a funtion of ansi cr imo.
While some detail might be lost due to washout, a CRT with LC has excellent shadow detail even in presence of some while in the piture.
Shadow detail can be lowered or skewed by processing, improper gamma and improper brightness level and some cases in torch mode.
White clipping has nothing to do with ansi cr AFAIK. Most digital are very prone to that. Some can be corrected by finding the right gamma and proper contrast level and some always clip the white. In CRT, there are blooming involved in higher contrast level where contrat curve is no longer linear.

In my first post I stated: "The CRT with sunlit snow at noon, you see the hills and valleys slight outlines, which are invisible on digital."

That would be caused by crushed whites? The digital looks like one big bright white mess, while on a CRT you see the individual contours and slight color variations which show the slight hills and valleys in the snow path.

Yes that's it. :o But we haven't gone there, have we?

Actually it is. There are a few thing but a great example Darin Perrigo showed me when we were comparing my stack to my present projector more than a year ago now.

At the beginning of the film The Last Star Fighter there is a background of stars moving away all during the titles. When the white titles actually appeared on the screen, with the 3 chip they were there, when they came up on the stack the stars completely disappeared. Another example is the DTheater film Snow Falling on Cedars,a visually stunning film. In one scene the lead character is walking toward and then under a large dock. With the CRT there is nothing visible under that dock due to the nearly 50% split to the left of bright daylight. Objects of all sorts are clearly visible under that dock with the 3 chip. Although this is certainly a specific ,it dramatically illustrated what happens in demanding ANSI scenes.

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Art, do you think this might be because of front projection and not that it wasn't there on the CRTs. I'll have to try to find those movies to check it out on my set.
Also, what was the medium for "Star Fighter". I can't get D-VHS but I do have a player if you want to mail it to me. Are there any other movie scenes I could check? If digitals have gotten this good then they will be in my price range by the time my set quits. That would be good news.

Actually it is. There are a few thing but a great example Darin Perrigo showed me when we were comparing my stack to my present projector more than a year ago now.

At the beginning of the film The Last Star Fighter there is a background of stars moving away all during the titles. When the white titles actually appeared on the screen, with the 3 chip they were there, when they came up on the stack the stars completely disappeared. Another example is the DTheater film Snow Falling on Cedars,a visually stunning film. In one scene the lead character is walking toward and then under a large dock. With the CRT there is nothing visible under that dock due to the nearly 50% split to the left of bright daylight. Objects of all sorts are clearly visible under that dock with the 3 chip. Although this is certainly a specific ,it dramatically illustrated what happens in demanding ANSI scenes.


Perhaps I should have explained myself better. The strength in ANSI comes from the increased intrascene contrast in higher APL scenes. You don't just bump up brightness to regain lost details or to make up for lack of ANSI performance.

Do you think perhaps the loss of details you experienced were due to the lower base level blacks you preferred on the stack (some slight black crushing) along with lack of gamma tweaking? I am not saying there is no loss of detail at all. I'm sure if you put a very small black square in a white field on a CRT the square would likely be washed out.