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Discussion Starter · #1 ·
CR is a huge topic of conversation in this forum no matter what the actual thread is.


I've been reading about CRT's "perfect" CR with numbers up to 18,000:1.


I've been reading about DLP's increasingly improving CR to the low 3,000:1 nowadays with the HD2+ DMD.


I've also been reading about LCos' improving CR with the SXRD (2000:1 officially, but what most observers think may be 1000:1-1500:1)


And everybody knows about LCD Projectors and their Achilles heel: Poor CR.


Well, I don't know about you but the reference for me should be 35mm Film Projector CR. If a digital projector can beat that, it's doing pretty well don't you think?


My question is: WHAT IS THE 35mm Film Projector's Contrast Ratio?

Is it 1000:1?

2000:1?

3000:1?

Higher?

It should be closer to digital projector's CR's than CRT's because it's also a "bulb" transmissive technology.

How black are the inks/dyes used for film?


Any gurus out there with the answer? :)


Andreas
 

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I do not know and I can not give you a link, but when browsing the net I came across something that said film had 4 orders of dynamic range. My conclusion is that the number is somewhere betwenn 1000:1-10000:1. Anybody else that cares to comment?
 

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Discussion Starter · #5 ·
Well, if 2000:1 is the realistic expectation of film, what is with all the "experts" whining about DLP's and their "poor" contrast on top of the other single-chip-DMD issues (dithering, rainbows, etc)?

I mean, look at how rapidly the technology is advancing and nobody seems to be satisfied. We went from HD1's 1000:1 with 2x 3 segment color wheel to HD2.5 with 3000:1 with 5X 7 segment color with a brighter picture, almost no rainbows and much improved dithering...?


Shouldn't we just stop whining and enjoy the show? :)
 

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Quote:
Originally posted by Andrikos
Well, if 2000:1 is the realistic expectation of film, what is with all the "experts" whining about DLP's and their "poor" contrast on top of the other single-chip-DMD issues (dithering, rainbows, etc)?
The problem as I see it is that CRT people got spoiled with great black levels. I can understand not wanting to give up something nice once you've had it. For those of us just used to films in theaters, we can just be oblivious and there really isn't anything wrong with that.


In my case, I've started to get the black level bug, but I'll wait for digital to get there.


--Darin
 

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Discussion Starter · #7 ·
Darin,

Getting there meaning what? 5000:1?

10,000:1? 20,000:1?


It looks to me that in the near future (1-2 years) we'll be getting DLP's and probably LCoS too that go up to 5000:1.

Would that satisfy you? I can imagine that under most normal applications (home theater environment) that's as dark as you can get...
 

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Quote:
Originally posted by Andrikos
Darin,

Getting there meaning what? 5000:1?

10,000:1? 20,000:1?


It looks to me that in the near future (1-2 years) we'll be getting DLP's and probably LCoS too that go up to 5000:1.

Would that satisfy you? I can imagine that under most normal applications (home theater environment) that's as dark as you can get...
I figure William Phelps gets about 8500:1 with his calibrated G90 CRT, so that sounds like a good number to shoot for to me. However, I wouldn't reject 10000:1 or higher either.


For me there are other things to consider also, as even a real 2000:1 LCOS should look awesome to me.


My 1750:1 with my Sharp 10k tells me that there is still quite a bit of room for improvement over that. At some point it does fit the law of diminishing returns and so I probably wouldn't tradeoff or pay as much to go from 10000:1 to 20000:1 as I would from 2000:1 to 4000:1.


--Darin
 

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When I saw Matrix Reloaded at the century 21 (film), dark scenes never looked washed out, and when it displayed an all black field, it looked so dark that you can barely see the masking around the screen.


Blacks aren't quite like crt but it is close. CRT blacks are so black that you'll have a hard time seeing the screen when it is displaying an all black field. I still prefer the look of film over crt since it give brighter more convining daylight scenes.
 

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Quote:
Originally posted by jcebedo1


Blacks aren't quite like crt but it is close. CRT blacks are so black that you'll have a hard time seeing the screen when it is displaying an all black field. I still prefer the look of film over crt since it give brighter more convining daylight scenes.
I believe this description applies to an improperly calibrated CRT projector. A properly calibrated G90 or Marquee 9500, on an appropriate size screen, with a good source, will produces images very much like film.


William
 

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andreas

this is the wrong question.

the right question is how much you have in a normally cinema "on the screen"

that is important not what theoretically 35 mm film have!

35 mm film can have 1500 to 2000.

in practice in a normally cinema mostly you have lees than 1200 some times lees than 1000.

why?

just one sample they put a exit sign left or right on the screen.

there are so many bad planned cinemas.

thats why i have a black box.

ti measured many cinemas i think 2 years ago and they found much cinemas with less than 1000:1 cr!!!
 

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Quote:
darinp

At some point it does fit the law of diminishing returns and so I probably wouldn't tradeoff or pay as much to go from 10000:1 to 20000:1 as I would from 2000:1 to 4000:1.
You are right. Biological (human/animal) senses respond in a logarithmic way (compress the inputs) in order to deal with a wide range of values. Most people do not understand this.

Quote:
W.Mayer

ti measured many cinemas i think 2 years ago and they found much cinemas with less than 1000:1 cr!!!
I used to live in Poland where movie theaters were totally dark at that time. It is shocking how "bright" American theaters are.


Mike
 

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Discussion Starter · #13 ·
W.Mayer,

You're right about the type of question.

"True" CR is definitely different (and lower) than theoretical CR.

Although, this applies for both Cinema and Home Theater.

Not everybody has cave like environments for HT especially during the day.


MikeSer,

You're right US theaters are pretty bright probably for liability issues.


Andreas
 

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OK

So the real world cr on screen at the local cinema usually varies between 1000:1-2000:1 or so. My question now is related to the one that started this thread. How much dynamic range can you get from scanning the original film material? If that dynamic range is about 2000-3000:1 the advantage of crt would be black level and black level can be adjusted with digital projectors. Is it possible for a crt to display material shot on film and expand the dynamic range of the source?
 

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If the source has anything on it that is absolute black, requiring the complete absence of light, then wouldn't the source CR be infinite?
 

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What we should really be asking is what is the contrast ratio of real life?


The ultimate picture would be an accurate portrayal of reality,whatever the medium that is what we should shoot for,we should not try to emulate 35mm as the definitive picture-it is not.
 

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Quote:
Originally posted by Andrikos
Well, if 2000:1 is the realistic expectation of film, what is with all the "experts" whining about DLP's and their "poor" contrast on top of the other single-chip-DMD issues (dithering, rainbows, etc)?

I mean, look at how rapidly the technology is advancing and nobody seems to be satisfied. We went from HD1's 1000:1 with 2x 3 segment color wheel to HD2.5 with 3000:1 with 5X 7 segment color with a brighter picture, almost no rainbows and much improved dithering...?


Shouldn't we just stop whining and enjoy the show? :)
Well, if we were all to settle for Cineplex-style PQ's then we'd all just go get a used 35mm projector and shut-up. Unfortunately (or is that 'fortunately') we expect better presentation in our home theaters than at the Crappyplex Cinema.
 

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"What we should really be asking is what is the contrast ratio of real life?"


Real life has a pretty poor contrast ratio these days, largely due to light pollution. How many of you have had a good view of the milky way recently?
 

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Contrast ratio of real life is greater than that of your eyes are capable of without some time to adjust. Once you match that value, then you are just triggering contraction and dilation of the iris and not really gaining anything beyond that.


Got to see a demo of the technology shown recently at SIGGRAPH where they are baclkighting an 8 bit LCD system with DLP or LEDs with 8 bit range to end up with an effective CR of ~100,000:1 under ideal conditions.

http://www.sunnybrooktech.com/tech/index.html


Display was about the size of a 17" monitor, and he was running the same images on the laptop he was using to drive it. Pretty interesting to see the difference between a 350:1 LCD and this technology. Media was only still images, but the effect of realism this level of contrast imparts is pretty stunning.


They are targetting this at film editors and doctors studying medical scanning imagery (CRs of up to 8000:1 inherent in the media).


The resolution of the 8 bit modulated light source is not pixel per pixel, so the display is not fully accurate on a per pixel basis (CR within one of the larger backlight cells is back to the LCD panels CR, but that will fall different places in the wider range depending on the average brightness of the whole cell). This is explained at the above link.


Anyway, no question in my mind that a CR far beyond film's capabilities is VERY desireable. And to me, it is not just about blacks. There was an image at the demo of a candle studded chandelier in a castle or old house of some sort, and the stunning thing about the image was not the shadows, but how the flames stood out as being extremely convincing against the background of the room at normal brightness.


But then I have a PLV70 and a Highpower. So we all know where my preferences lie. :)


BB
 

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contrast depends also on the source and the display resolution. a fresh panavision transfer (using the best current material) with a fresh cinema projector on a not too large screen (say 30ft) is STUNNING in contrast and resolution.

an HD transfer of a movie looks contrastier than the dvd transfer, generally.

Generally, the panavision movies on dvds that I have, have superior contrast to 35mm movies. Not a general rule but something I often notice.

It's most likely due to less film grain, more vertical resolution used when filming (anamorphism).

But even a widescreen format such The swimming pool, to name a recent movie, can be stunning. A fresh copy I saw in a small theater (12meters scope screen, thus 9.44m in 1.85:1), was striking in contrast and resolution.
 
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