Newbie asks what tech is used in digital theaters - Page 2

Coldmachine,
The discussion was about every level of post-production for 35mm to digital. The part I quoted was about the projected image.

Reading Your posts in this thread I came to conclusion that You say a good BD transfer with a good home cinema projector will show greater resolution and details than positive print. How did You came to this conclusion ?
Watching or measuring ?
There are many faults in Your conclusions.
And many generalaties which can not be used in this situation about 35mm quality.

First of all,
You say You have a 35mm projection.
But what do You watch there ? Release prints from Your local cinema, or similar quality prints ? That prints are usualy 6th or maybe even 7th generation from OCN. Try converting MPEG4 to MPEG1 and vice versa 6 times.
What will You get than?

Second of all,
Have You ever scanned 35mm print and analysied it to a frame taken from BD or JPEG2000 for DCI.
If not, than Your "I saw it" conclusion, about resolution and MTF can not be valid. It is just a generality.

3.
Have You ever seen a 35mm direct print from OCN ?
Or a direct print made from 4k Digital Intermediate process ?
There is no 2k or HD projector which can come even close to color rendering,
shadow details, highlights of these prints...
All postproduction studios try to make their 2k projections to come close to the 35mm projection and not vice versa, and this is the first time ever to hear that BD with home HD projector is better than 35mm prints.

There are many issues when watching 35mm in local cinema:
bad/old/out of focus/ lens, strong ambient light, 6th generation print,...
And You compare the perceived sharpness of that print with brand new optics of 2K projector and perfect HT od Digital Cinema conditions.

This is not a valid comparision, since You do not speak about this local cinema print, but 35mm in general.

I do the 35mm Kinoton/2k Barco A/B
comparisions of the same materials all the time.
this is uncompressed 2k material, not some Lossy jpeg2000 or even worse mpeg4/mpeg2 blu ray compression.
And this is not just me. Hundereds of other people.
I have never seen in practice or heard from anyone that has made this comparisions, with a conclusion that their 35mm print was inferior to hd or 2k projection.

Just to remind You that in process of print from OCN or Intermediate materials there are no things like in BD:

Downconverting to HD, reducing color information to 4:2:2,
reducing bit depth to 8bit, noise/grain reduction (which degrades resolution and sharpness, so You have to add later artificial sharpening)
compression of 50-100 factor, if You compare it to uncompressed HD.
if You compare it to 4k the compression factor is 500.

At the very end, there is a thing called 3d LUT managment (cinetal ,filmlight, arri). People spend 10.000-30.000 $, trying to emulate film through 3dLUT on digital projectors and displays.

this is a long story and I already had a really long day at work ...

Stephan

Well that all depends on budget, there are outfits that have an HDCAM SR workflow following negative scan, so you get slightly less resolution compared to 2K, and somewhat lossy compression.

That is exactly my point.
You can not make absolute definite conclusions about something so broad like 35mm process, without presenting precise details, situations, workflow, measurments, tests, ...

Considering HDCAM-SR RGB 444 10bit compression,
it is more likely that You will see more artifacts from Spirit's (telecine) CCD camera noise than from SR tape

Regards

Stephan

Stephan, It would seem that you either misunderstood my point, or I failed to express myself adequately. I thought It was obvious I was referring to the performance of a 35mm display system, as seen at a commercial cinema, not a OCN. Thats why I differentiated between 35mm display, and 35mm capture (OCN).

Let me address a couple of points.


I understand what generation the prints are, without your use of exaggeration, which actually supports my point anyway. I also understsnd the effect of cascading MTF. That was the whole point I was making.


The comment about MTF certainly is valid. The MTF display material, for both systems illustrates that clearly. It has also be the topic of white papers. I believe ETC published on this fact. Displaying the same film on both systems makes this clear


I understand all that, but its not relevant to my point. I already stated that I was referring to the 35mm display system, not 35mm as a capture medium. Yes I have seen first gen prints.


Yet again you seem to have misunderstood me. I was not comparing BD and a domestic PJ to 35mm prints. I, very clearly, stated that I was comparing the entire display chain.

The vast majority of people here clearly see thier HT as providing superior PQ to a commercial cinema. Thats the point I was making.


It most certainly is a valid comparison, Both represent what is seen in actuality at a cinema.

I was not speaking about 35mm in general. Yet again I will state that I was clear in differentiating OCN with a 35mm display system.


Yet again I will remind you that I clearly differentiated between capture (OCN) and the results of the final display system, as seen at the local cinema. I was not referring to original materials as that is not what we see displayed.


Im fully aware, and never gave any indication that I felt contrary to that


Im also aware of of LUTs, and how they are used. Ive had the good fortune to be able to follow a number of productions, film and digital. large and small, from pre production to final release, but that's not relevant to the point I was making.

I hope you can now see the point I was making.

I am aware of the theoretical, and actual, performance of 35mm film at the capture stage. I am also aware of its performance, at the end of the chain, as a display medium. It was this latter I was referring to, as that is what we see when we visit a cinema running 35mm.

Hope this helps.

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Terrible analogy I have to say. Prints are usually struck from an internegative made from a filmed out graded DI so its more like 4 generations (N,IP,IN,print) Sometimes they are even struck from first generation neg.


Yes I have but he wasn't talking about comparing film scans.


Again yes. I'm very happy with a Barco DP100 and happily use it to sign off film work. Its fine in every single area with appropriate lutting. It has a slight tendancy to oversaturated reds in certain circumstances but is generally as good as print. If not better as there is a fairly wide tolerance in describing a print as within aims.


Been in them all then have we? Now who is generalising.
Again he is referring to resolution. I agree with him. You have more resolution available on the screen from BD on a decent 1080p projector than you see in a cinema : even with a rush print . Not much more but certainly more regardless.


Seems like a perfectly valid comparison to me , maybe you should reread what he has said.


Well now you've heard me telling you.


Most of the BDs I've looked at recently are 1080p extractions from 2k, no downponverting. Its pixel for pixel. 8bit and 4:2:2 component downsample (BD is actually 4:2:0 in case you weren't sure) will have little effect on sharpness characteristics in terms of MTF.

DNR is a seperate issue.

Compression does instigate some lack of detail in certain situations so whilst I would not describe BD as being as sharp as 2k but its certainly sharper than a 35mm print.

I have compared it to uncompressed HD and 2k log and its actually been feature film imagery I created and spent months staring at.


RGBHSI correction about sums it up. ( why do some people insist on mystifying these simple concepts) I manage it with software that costs $3000 and $1000 displays for 90% of my work.

I suspect you'll find a few people on here who are not particularly impressed by the fact you have spent some time in a building with a film scanner and have some sort of familiarity with "2K". Maybe you should re-evaluate the level of expertise you seem to be assuming you have in these areas relative to many of the members you'll find on this forum.