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This topic comprises 3 pages: 1 2 3
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Topic: Barco 32B color Alignment Issue
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Ioannis Syrogiannis
Expert Film Handler
Posts: 147
From: Reykjavík, Iceland
Registered: Jun 2005
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posted 12-21-2018 01:23 AM
Well, I wouldn't trust a monocular for the convergence procedure and I would even try to remove the glass of the port that I am seeing through. And If I did, I would definately need to validate from up close afterwards. Convergence issues are not the prerogative of the lens and the light engine, it can as well be a glass between the screen and my eyes that refracts light in a different angle for different wavelengths. I have before spotted issues (they are easily detected and acknowledged during the procedure) with my eye glasses and given that my eyesight is not too bad, I prefer assisting the procedure without them. Usually, I ask for help from the projectionist or another person to whom I previously explain the task. When a convergence camera is handy, I definitely go for it. I can't possibly say if the monocular you are using is Hi-Fi, but in my (short) experience, there weren't any I could trust for such applications where titles and subtitles could end up loosing sharpness and being... laureated with different colors.
Dave has a point there. Changing a light engine absolutely poses a need for such checks. And taking into account the stakes there, the minimum knowledge of doing the checks, being familiar with the equipment and its mode of operation in such a way, is a prerequisite for changing the light engine.
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Leo Enticknap
Film God
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Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000
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posted 12-21-2018 10:48 AM
quote: Ioannis Syrogiannis Convergence issues are not the prerogative of the lens and the light engine, it can as well be a glass between the screen and my eyes that refracts light in a different angle for different wavelengths.
True, but that glass is going to be in place when the system is in regular operation. I take your point (especially if the port glass is angled), but surely it won't work to set the convergence with the port glass removed from the light path, because when the glass is replaced, the convergence will be thrown out.
By the same token, color calibration should be done with the theater's house lighting set as it would be during a show. If you shut the exit boxes and Tivoli lights off (for example, and I've seen techs do this) and shoot the colors in total darkness, the reading from the red, green and blue test patterns will not be exactly the same as it would be in show conditions. Same for tuning with the HVAC shut off, etc. etc.
Agreed that Waqar would likely benefit from a visit from a tech, and/or to do the Barco installation and basic maintenance school. Don't know if they do them in Pakistan, though. To be fair to him, swapping out a light engine on a B series is not that complicated: the only real gotcha is being sure to put all the multi-pin connectors back in the correct jacks on the backplane (I almost wonder if one or two of them got swapped, thereby causing his current issue). But as Dave and Ioannis point out, there are adjustments and calibrations that need to happen once you've done that, which is where it seems that Waqar is getting a bit stuck.
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Ioannis Syrogiannis
Expert Film Handler
Posts: 147
From: Reykjavík, Iceland
Registered: Jun 2005
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posted 12-22-2018 08:02 AM
Leo, what I was talking about there: "it can as well be a glass between the screen and my eyes" is not the projection port glass, but the glass of a window through which I see the screen. Often enough, that is not one and the same. That is the reason I made that rather peculiar choice of words, instead of mentioning the projection port. The same reason that I got to mention my eye glasses just after. What I want to avoid is any interference between the screen and me, not between the projector and the screen. If I can't, I go with help from another party, as I already mentioned.
As for learning to do the convergence, one may learn to follow the procedure from another, even if they don't sit a school for it (the best case scenario). Indeed, the courses can be as far as Noida, India, if someone lives in Pakistan (I, myself, had to go to Kortrijk). In any case, though, I strongly believe that if someone doesn't manage to go through it with the detailed instructions of the Barco installation manual, wouldn't be better or more securely guided via a forum, where others are mostly based on assumptions and don't actually know what the situation is.
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