Light leaks on a Barco DP2K-20C

[Mihkel Salk]

I'm having similar problems to this thread posted 10 years ago - a strange flare/light leak on the left lower side of the image. It's more visible with Flat macro (we have a Scope screen) but it's still there on Scope macro as well, just projected outside the screen area.

It moves when shifting the lens and is visible on both sides of the port glass. No luck replacing the lens either - the problem occurs with both lenses we own (R9855936 and R9855932).
I realigned the lamp and even tried a brand new replacement lamp. You guessed it - the problem's still there.

The masking is correct and it doesn't seem to be a digital problem, it's more likely a problem with the hardware. The projector is a Barco DP2K-20C that was refurbished at Barco some months ago.

I tried taking some pictures of the reflection to illustrate the problem. Sorry for the fingerprints on the last picture - they're on a random piece of plywood held outside the enclosure, not on the port glass.


ref1.JPG

ref2.JPG

ref3.jpg



Does anyone have any advice on how to get rid of the problem?

Thanks!
Mihkel

[Steve Guttag]

Use masking on your screen. Projectors are not perfect (and neither were film projectors). They all have a degree of unwanted light scatter due to the nature of them. The lens doesn't know what is desired versus undesired. Note too, when showing "Flat" movies, you are not using the entire DMD in width. You are just ussing 1998 pixels of the 2048 in width. Those off pixels are going to show up...just not as bright. But again, use masking. That is what it is there for.

If you really want to see a pretty light show, look at what comes out of a CP2210/CP2215 projector. You get a rainbow out of it outside of the image area (upper-left corner, significantly outside of the image area). One can normally mask the Christie's leak at the projection port.

[Mark Gulbrandsen]

The first thing I'd do is clean that really filthy port glass. And if it's just plate glass replace it with Schneider AR

[Mihkel Salk]

Use masking on your screen. Projectors are not perfect (and neither were film projectors). They all have a degree of unwanted light scatter due to the nature of them. The lens doesn't know what is desired versus undesired. Note too, when showing "Flat" movies, you are not using the entire DMD in width. You are just ussing 1998 pixels of the 2048 in width. Those off pixels are going to show up...just not as bright. But again, use masking. That is what it is there for.

If you really want to see a pretty light show, look at what comes out of a CP2210/CP2215 projector. You get a rainbow out of it outside of the image area (upper-left corner, significantly outside of the image area). One can normally mask the Christie's leak at the projection port.

Hello,

do you mean digital or physical masking? If digital, then the masking is done for each macro and set up using Barco's framing chart.
If you peant physical, then unfortunately we don't have masking curtains in our cinema. One can dream that we'll get around to buying them one day, but that's not the case at the moment.

The reflection is definitely not from the unused part of the DMD chip. The brighter bars have always been there and don't bother me that much. It's the flare/reflection that's giving me headaches.

The first thing I'd do is clean that really filthy port glass. And if it's just plate glass replace it with Schneider AR

Hi,

the port glass is spotless and as stated in my original post: "Sorry for the fingerprints on the last picture - they're on a random piece of plywood held outside the enclosure, not on the port glass." .
I'm not sure if the glass is from Schneider, but it's definitely not normal plate glass and is meant for projection booths. The reflection is also visible from inside the enclosure, so that'd leave the port glass out of the equation.

[Steve Guttag]

I do mean a physical masking.

[Mihkel Salk]

I do mean a physical masking.

Thanks.

I'll check if I can mask inside the enclosure so that it doesn't interfere with the scope image.

[Marco Giustini]

There is an old info-T documenting that and, as it has been said, there is no solution but using some physical masking on the window - which you really need a good clean!!!



infot.JPG

[Marcel Birgelen]

The fact that it appears as a blue spot indicates that it's most likely something in the blue light path. It's hard to tell from a few photos if it is within the tolerance range, because like indicated before: most projectors leak some light outside their active area.

If it's outside the scope image frame when projecting in flat, you should be able to get rid off it by taping that area off on your porthole window. If you have physical masking on the screen, you should definitely use it, as it greatly improves contrast and will effectively get rid of stray light falling on the unused part of the screen.

Also check if your porthole glass itself isn't the culprit. If you put a white paper in front of the porthole, you should be able to see it, if you don't see it, it may be caused by the porthole itself. (Please keep in mind that stuff can get very hot in front of the lens...)

[Jarod Reddig]

Maybe look for some used curtains or some bulk fabric and make your own masking. When i had a 2.35 screen (now have Flat, gunna go back in next house) I made my own in my home cinema for about $100. Granted my screen was only about 11 ft wide. Wasn't perfect but made a huge difference compared to seeing the pillarbox bars on Flat and 4:3; or your reflection issue.

[Sean McKinnon]

If you can find a local theatrical supply company you could buy a roll of Duvetyne for about $5 a yard and use it to wrap some 2x6 pieces of lumber to create a hard border, then you could wrap some plywood to make a removeable mask for flat. It is pretty cheap this way but someone has add or remove the panels whenever you go from flat to scope. I have seen them be hinged but I am not crazy about that. Depending on what you have for room on the sides of the screen you could get some kind of track https://www.mcmaster.com/tracks and make them slide out of the way.

Of course you want to make sure that you do not block your left and right screen channel speakers. If this is the case you would have to get some "sound transparent" fabric https://acousticalsolutions.com/prod...oustic-fabric/ and frame out the area you would need to cover with 1x2 lumber while keeping the center open and cover with the acoustic fabric.

The problem with just hanging a piece of black curtain is that you wont get a nice hard edge and the sound absorption issues.

Just some ideas on how you could add some masking for relatively short money.