Film-Tech Forum ARCHIVE: Barco DP2K 20C How to calibrate colours?

This is topic Barco DP2K 20C How to calibrate colours? in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Janusz Antkiewicz (Member # 5118) on 09-24-2011, 10:11 AM:

Hello fellow projectionists [Smile]

I'm looking for somebody who would help me with the following problem.

On one of the machines at our location (we use Barco DP2K 20C projectors with Doremi servers) we seem to have an issue with colour management.

When I put a this rainbow-like test pattern (vertical bars of different colours: white, red, green, blue etc.) it looks as if in some places the neighbouring bars overlap each other just by a tiny bit; very little but visisble. Showing a film with subtitles we get sort of greenish shade to white text.

It's got something to do with colour calibration, that much I can say [Wink]

. However, not being an expert at digital cinema I wouldn't want to do some damage to the equipment, hence my presence on this forum.

So if you know what to do and have some time your help would be very much appreciated.

Kindest regards

Posted by Randy Stankey (Member # 64) on 09-24-2011, 10:20 AM:

Sounds like it's more a problem of alignment than a problem with color calibration.

If it was color, things would appear to be the wrong color. Blues would appear greenish, Reds would appear yellowish, etc.

If you have a problem with one color overlapping another it could be because one of the color chips in your light engine isn't lined up with the rest. (e.g. The green chip isn't precisely aligned with the red and the blue.)

In your case, I would definitely seek the services of a technician who knows how to do this type of troubleshooting and alignment. It's not "difficult," per se but it must be done correctly. If you try to fix it yourself, you could make the problem worse.

Posted by Dave Macaulay (Member # 813) on 09-24-2011, 03:07 PM:

There should be a test pattern labeled something like "convergence-C" or similar. Display that and see if the places you see the three colors beside each other are in a straight line. They should be aligned exactly at each place you see them. The numbers and arrows are guidance for aligning them, but I recommend not trying that yourself.
If you de have a color calibration problem, it usually shows up as weird skin tones not as greenish subtitles. Color calibration requires a color measurement instrument.

Posted by Mark Gulbrandsen (Member # 72) on 09-25-2011, 08:00 AM:

I once had a cracked integrator rod that was causing strange ghosting and color splotches... I thought one of the prism's on the light engine had cracked or become dislodged.... and the crack was tiny and n the face of the integrator.

Mark