Film-Tech Forum ARCHIVE: Chromadepth 3D

This is topic Chromadepth 3D in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Ken Lackner (Member # 1002) on 03-22-2007, 09:19 PM:

When doing research on various 3D techniques, I started thinking about a 3D laser show I saw at the Vanderbilt Planetarium when I was a kid. The glasses provided the 3D effect by making each color of the spectrum appear to be at a different depth. Pretty cool stuff. I started Googling it, and found out the technique is called chromatic dispersion, or ChromaDepth . You can look at any photograph or drawing, and the colors will have depth. So if an artist is creative, he can create a peice of content that has the correct depth by correctly coloring the objects. The website even says that certain films, such as Mulan and Batman & Robin, have lended themselves quite well to the process -- unintentionally. So the question here is why haven't any film makers taken advantage of this techniuqe to intentionally produce content that lends itself to this process? There would be NO special equipment required to project the films, glasses are dirt cheap, and the content would look just fine without even wearing the glasses. I think it would be great to see films that use this technique for 3D.

Posted by David Zylstra (Member # 4230) on 03-22-2007, 11:05 PM:

Actually, I think a similar process is being used for Dolby's 3D system that was showcased at ShoWest 07 - they are using dichroic lenses for each eye. As I understand it there is a modification needed in the projector light path as well as expensive glasses. The process was explained to me and I don't understand it completely enough to re-explain it.
Two issues were noted - the current glasses are expensive and if you look to the edge of the screen without moving your head there is no 3D effect - both issues are being worked on and price will come down and I'm sure they can work out a better lens design.

Posted by Monte L Fullmer (Member # 2797) on 03-23-2007, 03:09 AM:

During projection, the left and right eye images from the digital projector(s)are polarized perpendicular,to one another as they are projected onto the screen by means of diffuser filters.

By wearing special eyeglasses with lenses polarized in their respective directions to match the diffused projection, the left projector eye image can be viewed only by the left eye since the polarization of the left lens will cancel out that of the right projector eye projection, and the right projector eye image can be viewed only by the right eye since the polarization of the right lens will cancel out that of the left eye projection.

If you take two pairs of polarized glasses and match up the lenses then rotate one lens, you will notice that the minute lines in the two lens material either lets light in totally, or goes completely black when the lenses are at right angles to one other.

Goes the same for polarized sunglasses - match up the lens, look through it and rotate one lens 90 degrees...image goes from grey to solid black.

Have some fun with this 3D-site here...

Posted by Ken Lackner (Member # 1002) on 03-23-2007, 03:38 AM:

This system is actually very different from the Dolby 3D. As far as I know, with Dolby 3D, there are still two images -- right eye and left eye -- projected on screen. As with other methods, the glasses provide a way of filtering so that the left eye image is only visible to the left eye, and the right eye image is only visible to the right eye. With ChromaDepth, you do not have two images. There is a single image that will look perfectly normal without glasses. But put on a pair of the glasses, and the magic happens. Any color photograph, website, magazine article, brochure, etc... will have depth to it. An artist can, therefore, design a picture to have the proper depth by carefully choosing his colors, knowing that red will appear closest to the viewer, blue will appear furthest away, and other colors will be somewhere in between.

I don't imagine it would be all that difficult to apply this creative process to film making. As I said, no special equipment would be required to project the film, and the film would look perfectly normal to anyone not wearing glasses; it would merely lack the depth the glasses give it.

EDIT: Looks like Monte was busy typing the same time I was. That's some good info on ploarization, but what does it have to do with this topic? Neither Dolby 3D nor the system I mention use polarization as the means of achieving 3D. In addition, if we want to be techincally acurate, the Real D system (which I assume you are talking about since you say, "During projection, the left and right eye images from the digital projector...") does not use linear polarization, it uses circular polarization .

Posted by Monte L Fullmer (Member # 2797) on 03-23-2007, 04:20 AM:

Thx for the correction on polarization.

Posted by Chris Parry (Member # 4178) on 03-23-2007, 01:58 PM:

With all this talk of 3D, one thing I know for sure...

One-eyed people are gonna be pissed.

Posted by Louis Bornwasser (Member # 3063) on 03-23-2007, 03:00 PM:

Find a way to eliminate the "glasses" and you will have som ething marketable! Louis

Posted by Phil Hill (Member # 371) on 03-23-2007, 04:30 PM:

quote: Chris Parry
One-eyed people are gonna be pissed.

Hey! Hey! HEY! [Wink]

Posted by Tim Reed (Member # 137) on 03-23-2007, 04:43 PM:

Phil! ROFL!!! [Big Grin]

Posted by Brian Guckian (Member # 1678) on 04-02-2007, 04:20 PM:

quote:
Find a way to eliminate the "glasses" and you will have something marketable! Louis

There have been developments in single-user 3D displays where the viewer does not require glasses...the potential market here being for laptops, PDAs, mobiles etc.

For group viewing, perhaps holography is the way to go to finally eliminate the glasses?

BTW the new Dolby system AFAIK is a development of the traditional anaglyph method. However, much more precise colour filtering is used, and two different spectra, each containing complementary RGB components, are fed to each eye. Presumably, high-speed sequential projection of Left-Eye / Right-Eye images is also employed. The glasses are reported as being inexpensive, as well.

The Chromadepth technique is very interesting, but since it is colour-dependent it looks as if it may be restricted to artificial imagery (if red is the colour that appears closest, as they point out, then it follows that all close objects must be rendered red), which probably explains its lack of take-up by the industry.

Posted by Bill Enos (Member # 440) on 04-02-2007, 10:08 PM:

If 3D ever takes off, congress will pass a law making it unlawful to discriminate against the one eyed and it will all be over.

Posted by Ron Curran (Member # 3631) on 04-03-2007, 12:43 AM:

Yes, and there are a lot of one-eyed politicians.

Posted by Ken Lackner (Member # 1002) on 04-03-2007, 05:49 AM:

quote: Brian Guckian
The Chromadepth technique is very interesting, but since it is colour-dependent it looks as if it may be restricted to artificial imagery (if red is the colour that appears closest, as they point out, then it follows that all close objects must be rendered red), which probably explains its lack of take-up by the industry.

I would agree with that. But their own website says that Mulan looked really good in 3D with a pair of Chromadepth glasses, and it was totally unintentional. I'm not an animator or film maker, but I don't imagine it would be too difficult to make animated films that take advantage of the technique. How realistic are the colors in many animated films anyway?

Posted by Brian Guckian (Member # 1678) on 04-03-2007, 08:21 AM:

True - but note that the other methods can be used for all kinds of material. Once again, the exhibitor is faced with format overload! [Eek!]

But it would be nice to see a demo...

Posted by Frank Angel (Member # 248) on 04-04-2007, 12:26 PM:

There was a process that I recall reading about I believe in American Cinematographer many years ago when they had an outstanding issue devoted entirely to 3D, I can't recall the name it was given, but it used some kind of prism system in the camera lens that rendered an anaglypic image, but unlike standard (horrific) anaglyphic 3D, it was 2D compatible. The way it work was, it kept the subject in perfect focus and at 100% convergence, so it's colors were not separated into red and green and it looked like any normal 2D image. BUT, everything around it, i.e., the stuff in front of it and behind it were either converged in front of the screen or behind the screen and the prism arrangement in the lens cause the green and red images to separate.

The result created a very watchable image without glasses because the primary subject in the image was not a double image but a normal, combination of the red/green split. However, if you put on anaglypic glasses (yuck), you did see depth. AC used one of these semi-anaglyphic images on it's front cover and it was quite impresive. And of course the beauty of it was that it was totally compatable with any recording/playback medium....TV, print, film, etc., with nothing more that the special taking lens. The playback system is untouched.

The big drawback (besides the anaglyphic issues) is that to get any kind of depth, you need to always have shallow focus, i.e., the subject needs to be in focus whilst everything else needs to be soft or totally out of focus. This would be irksomely limiting to any cinematographer. But it is a cute gimmick, and you probably could get away with applying it to some bad TV show....American Idol! tonite in Depth-o-Vision.....and then tie it in with some fast food manufacture....Get your special glasses only at MacDonalds.

Naturally they would claim it was the first time ever that a TV show was being broadcast in special, new Depth-0-Vision. Everyone would get all excited, but then they would buy their fries with the special box at MacDonalds and peel off the cardboard glasses on the side and realize, Hey, these are just the same freakin crappy red and blue glasses they always use! And that would be the last time Depth-0-Vision would be used, but for that one time, lots of people would make lots of money. Aint that the way it works?