Film-Tech Forum ARCHIVE: Merits of CRT Projectors

This is topic Merits of CRT Projectors in forum The Afterlife at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=12;t=000510

Posted by Peter Berrett (Member # 672) on 06-27-2006, 06:22 AM:

Hi all

I notice that there has been very little discussion about the merits of CRT Projectors on these forums.

I have been looking around on the Internet and apparently the color reproduction and contrast ratios of these projectors is very good. The main difficulty appears to be that they do not give quite as much light as the lcd and dlp models. But they do not have rainbow effect and black means black.

What do readers think of these projectors? Are they suitable (maybe ideally suitable) for home theatre use?

That aside there appears to be some scope for buying second hand projector cheaply. Do the older models give good picture quality?

Would CRT be your choice for non-film projection in the home environment?

NOte to John Pytlak. Please comment on color reproduction of CRT sets vs LCD, DLP.

Regards Peter

Posted by John Pytlak (Member # 331) on 06-28-2006, 09:29 AM:

quote: Peter Berrett
NOte to John Pytlak. Please comment on color reproduction of CRT sets vs LCD, DLP.

For direct view monitors, CRT is still preferred to other technologies for color reproduction. Likewise, for consumer level rear screen projection sets, CRT probably still has an edge for color reproduction.

For high end projection using three modulators, DLP, LCOS and D-ILA can be very good, especially with well designed "color management" using 3-dimensional LUTs:

http://www.kodak.com/US/en/motion/products/dlmanage/kdm.jhtml?id=0.1.4.24&lc=en

quote:
KODAK Display Manager System—powered by KODAK Color Science—calibrates, characterizes, and leverages advanced 3D LUT technology to ensure all display devices—including digital projectors—are presenting a consistent visual reference. Saving time and streamlining collaboration throughout the production process.

Posted by Frank Dubrois (Member # 3042) on 06-28-2006, 11:10 PM:

I had one of these things for home theatre once. They put out about 300 lumens, compared to 1000-2000 of a standard LCD or DLP projector. Also, if you plan on hanging these on your ceiling, they weigh in at about 125lbs. The picture IS better in my opinion, but not THAT much better to have to deal with the size and lighting requirements.

Posted by Mark Gulbrandsen (Member # 72) on 06-28-2006, 11:50 PM:

Don't forget that you can also "Stack" CRT projectors and pretty much perfectly converge them... this is something you can't do with any other type of video projection source. I still prefer the look of a good Barco CRT based video projector over DLP or LCD type for NTSC and even some hi-def. Contrast range is greater, coloremetry is better, and the image is also sharper. The other technologies are quickly catching up though.

Mark

Posted by Frank Dubrois (Member # 3042) on 06-29-2006, 10:01 AM:

One problem you get with a used CRT projector is weak guns. The blue color is almost always very weak and usually the first to fade out. What you get then is a color that you cant focus. Everything that is brightly colored gets a blue halo effect around it. usually just replacing one of the CRT's isnt an option as it will then be stronger than the other other colors. Replacing all three isnt cheap either. You'd have to have one huge home theatre to stack those CRT's. Also..unless its a newer model, converging the colors on ONE unit is a process in itself. I think the newer ones are a little easier to set up, but the older ones took a long time with a small screwdriver converging each color onto another. I'd still go DLP. Some of the newer DLP units can get better than 10000:1 contrast (so they claim).

Posted by Mark Gulbrandsen (Member # 72) on 07-05-2006, 09:39 PM:

Actually the blue CRT only amounts to about 12% to 14% of the overall image in a color tv. This is the way the NTSC system was designed. Although replacing all three is best you can many times get away with replacing just the blue crt. Also the human eye is least sensitive to blue so your blue tube would have to be really bad before it becomes objectionable. Alot of projection CRT's use a type of blue phosphor that has a tendency to bloom and you can never get an absolutely sharp spot or scan line... it just depends on what blue phosphor the manufacturer uses. My Mitsubishi has the type of phosphor that bloomns slightly but the red and green tubes are sharp as a tack. The Blue phosphor used in Barco's crt's is great and probably very expensive as its sharp as a tack. This can also be seen in tri-color crt's where the blue scan can never be focused quite as well as the red or green....

I dno't think that any DLP or LCD sets will ever look as good as a really high quality CRT based set can... crt's have a look all of their own and at present are still capable of alot more resolution. I don't think manufacturers are worried or even trying to replicate that look... crt's will literally just fade away in the next 5 years or so. I always felt that the crt vs. DLP or LCD had a difference in look siomilar to the difference in look between Eastman Color and I.B. Tech with the CRT being the latter!

Mark

Posted by Aaron Garman (Member # 1653) on 07-14-2006, 03:29 PM:

Also remember, if you plan on displaying any still images from say a PC or even video games, CRT's can burn in images. I always liked the way CRTs looked too, but convergence can be fun, although I actually enjoy it! A couple questions for everyone else: does Runco still make a CRT front projector and how exactly would stacking two (or more?) CRTs work? Do you just converge them both to one point, running the same feed of video into each unit?

AJG

Posted by Mark Gulbrandsen (Member # 72) on 07-14-2006, 07:13 PM:

There are or were special stands available that allowed one to stack another projector on top of an existing one... double the image brightness... double the convergence headache which when done by remote is not all that bad... on the set convergence controls are a huge pain though.

Mark

Posted by Paul Mayer (Member # 355) on 07-14-2006, 09:10 PM:

Aaron, you might want to take a look at this old thread (it's not long):

Superimposing 2 Data Projector Images

That thread was talking about digital imager machines, but the basic principles are the same with CRTs. You're just having to do the same thing with individual colors on each machine. My sequence for doing a two/three/four projector overlay was always the same: pick one machine to be the primary and do that machine first. Once machine #1 is done, converge one color of machine #2 onto the green image of the first (some people liked to do green on green - I usually did machine #2's red onto machine #1's green). Once one color on machine #2 is done, converge the rest of machine #2's colors.

Like Mark mentioned, having remotes to do this makes things A LOT easier. Also, allow for plenty of warmup time - I used to wait at least a half hour before starting the convergence process.

Posted by Mark Gulbrandsen (Member # 72) on 07-14-2006, 10:31 PM:

quote: Paul Mayer
I used to wait at least a half hour before starting the convergence process.

I don't know Paul,

If I had worked in Vegas as you did I would have converged on the nearest buffet immediately... no need to wait even a minute let alone for 30. I always do the warming up in the process!

Mark

Posted by Paul Mayer (Member # 355) on 07-15-2006, 12:22 AM:

Hmmm... Pig out during the warm up. Never thought to do that at the time. I usually had lots of other gear to setup - tape machines, font generators, cameras, switchers. Plus had to do system timing, since as projectionist I was often also the TD or EIC. By the time I got all that other stuff done, the projectors would be nice and stable and ready for tweeking.

I usually tweeked the machines during everyone else's lunch break. That way I could have a dark room to do the work.

One thing I really miss about being a 'Vegas stagehand back in the day was the food. Most of the hotels fed their staffs very well. The 'help's halls' at some of them were as nice as any public restaurant on the property. We ate well - and for free. [Big Grin]

Posted by Phil Hill (Member # 371) on 07-15-2006, 12:38 AM:

9x ceiling-mounted Sony VPH-1252's seamlessly edge-blended and line doubled for a continuous 360-degree image at a dance club by night, Video Circlevision theatre by day. 700-Lumen CRT projectors rule!

Posted by Mark Gulbrandsen (Member # 72) on 07-17-2006, 07:41 AM:

Phil, It take one person a week to re-tube all those [Eek!]