Film-Tech Forum ARCHIVE: Barco/Kinoton with poor black

This is topic Barco/Kinoton with poor black in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Marco Giustini (Member # 4544) on 09-27-2016, 01:28 AM:

Hi there
I have a Kinoton S2 machine where black is in fact an awful brownish halo on screen. Apparently it's always been like that.
The optics have been cleaned but that did not improve the situation.
I guess there is nothing I can do without a new engine, I was wondering what could possibly cause that issue.
Thanks

Posted by Dave Macaulay (Member # 813) on 09-27-2016, 05:49 AM:

What do you mean by "halo"? A light pattern, or a flat field of brown?
The Barco light engine contrast depends on the DMD chip used. I don't think Kinoton used the small chip systems, so a 2K 1.2" DMD projector should have pretty good contrast and blacks that look like dim gray on screen in a dark room. The 1.4" 4K chip contrast is not as good and black is a brighter gray, same as the .69" 2K ones (these are really 1/4 of a 4K chip).
A "brown halo" sounds like something is screwed up. I doubt if the electronics are doing that, but you can use the TI "ICP and Enigma Control Program" to "park" the mirrors and get the darkest black possible to see if the black pattern is somehow corrupt or one of the various correction matrices is off.
Dirt in the LE optics can cause contrast loss and higher black level: light is scattered by the dirt and some will go out the lens.The Barco design is not prone to internal contamination, though.

Posted by Alan Gouger (Member # 543) on 09-27-2016, 08:01 AM:

If you run a multi screen momentarily swap the lens from another machine to eliminated lens as the cause. If its not the lens run a separate R,G,B test pattern to see if the issue is isolated to one of the DMDs. If the issue shows up on all test patterns it could be a bad integrator rod or light pipe adjustment. Also check your folding mirror for contamination.

Posted by Marco Giustini (Member # 4544) on 09-27-2016, 11:14 AM:

Hi,

It's a flat field of brownish grey. Basically the projector has poor contrast and black is in fact slightly brownish.

I did not think of the fold mirror thanks -- I'll have a look.

DMD's are 1.2", so it should be the best possible picture in the DLP world.

Swapping the lens is also a good idea. Unlikely but you never know. You don't want to swap the light engine to find out that is still showing the same issue.

Thanks!

Posted by Pete Naples (Member # 761) on 09-27-2016, 03:12 PM:

I don't remember selling one anywhere around Reading!

Fold and main mirror can be adjusted on a Kinoton, but you really do need the factory tool.

Posted by Marco Giustini (Member # 4544) on 09-27-2016, 03:34 PM:

isn't the fold mirror the one in the light engine? I've always called the other one 'cold mirror' as it cuts IR as well.

Do you work in Dunfermline only Pete? [Smile]

Posted by Pete Naples (Member # 761) on 09-27-2016, 03:57 PM:

As much as possible, yes, although I'm yanking your chain [Wink]

In the Kinoton lamphouse you can adjust the position of the main (collector) mirror and the cold (fold) mirror, prior to the light engine. It's best to adjust these using the Kinoton factory tool which clips to the light pipe cooling plate.

I can't think how these being misaligned would kill the blacks, but I guess one must be open minded.

I think I'd be looking at light pipe, notch filter, LE condition and lens.

Does yours have the heat filter or condensing lens between the fold mirror and the light pipe?

Posted by Marco Giustini (Member # 4544) on 09-27-2016, 04:59 PM:

heat filter.
yes, you never know what kind of black optical magic happens inside that block. That said I understand it's been like that since day one (don't ask!) so it should not be anything that has degraded over time. I have the feeling the RED DMD area is contaminated and that is scattering some red light around. It's a shame since as I said those should deliver the best picture in DLP world.
Thanks for your input.

Posted by Pete Naples (Member # 761) on 09-27-2016, 05:17 PM:

Generally they do put out a stunning picture Marco. It's a shame this one slipped and wasn't sorted.

Last year I attended one in Ireland which hadn't been serviced properly since install, it had been attended to by others who didn't know Kinotons.

When I left, the theatre owner was knocked over. It looked better than his other screens with Barco which were all about 2 years old. The Kinoton was at that point probably 5 years old and hitherto untouched. I'm not suggesting that the Kinoton is actaulyl any better than a Barco, but you're right it has everything going for it.

Posted by Frederick Lanoy (Member # 5416) on 09-27-2016, 05:43 PM:

Marco : is it always bad during a whole movie ? Or does the problem "evolve" (getting better, worse...) ?

I experienced a very troubling problem with a DP3000. The image looked really awful (no contrast, poor colors...) but only during the five first minutes of the trailer. Audience complained then... no problem anymore. Although, i did not fix anything.

Actually, there was a leacking of cooling liquid in the engine. With the heat of the lamp, it had evaporated quickly within the first five minutes of the show. We had to change the engine.

Posted by Marco Giustini (Member # 4544) on 09-28-2016, 01:30 AM:

Hi Pete
Sure I know the projector should be able to deliver a very high quality picture, that's why it's disappointing to see a picture worse than a the one that a 0.69" can deliver!
Frederick
No, the issue is constant as far as I can see.

Posted by Marco Giustini (Member # 4544) on 09-29-2016, 01:29 AM:

The lens is not guilty. I tried a different one and the issue followed the engine.