light spill from background surrounding video image

[Bob Sturgess]

Help. This may well have been asked before, but.... I am projecting a small AVI clip but the rest of the background not filled by the image is very bright when projecting on to a blackout out stage. Am I missing something. fine between video clips but once launched the background which appears black on the monitor is light grey on stage?
Any help appreciated

[Mike Daniell]

I've just tried this here and the background around the clip is black, as it should be. Could you email me a diagnostic file? You can create this file by selecting 'Create Diagnostic File' from the drop-down menu displayed when you click the Help button in the main window. The file will be saved in a folder named "SCS Diagnostics" under "Documents" or "My Documents".

[jmgordon]

This can be an issue with the contrast ratio of the projector, which may not be able to produce pure black (or no light!). It is for this reason that people use mechanical shutters to blank projectors when not producing an image. A grey, rather than white, screen will help, or even blackout material. It is also a question of perception by the eye.

Malcolm

[Bob Sturgess]

Thanks for responding.

Mike have emailed you.

Malcolm

I think you have the truth of it. The LED projector is unable to produce pure black. Looks to me like an assumption has been made as to the likely ambient light in common venues. There has then been a decision to accept that in most circumstances it will not be an issue. For instance (having just tried it) projecting in the living room with curtains open means virtually unnoticeable. Draw the curtains and immediately noticeable. Of course I am asking the projector to do something in an environment it is not designed function in. That is, in a darkened hall where we are trying to eliminate as much light as is possible for those all important blacked out scenes.

Shuttering is the answer but not adaptable enough; short of someone standing in front of the projector playing shadow puppets to screen out the variable areas of spill!

Another idea might be to raise the stage lighting level sufficient to override the spill. Maybe an atmospheric dark green or deep red. Oh well, back to the drawing board. One thing for sure, it is not an SCS problem.

All ideas gratefully considered before show time next week

B

[Buyaicia]

Check for DLP type projectors.
This projection method has better black.

DLP defines the projection method and is not dependant of the light used.
This means there is LED projectors with DLP or LCD.
http://www.purple-cat.co.uk/dlp-or-lcd-projectors-guide

Regards,
Lluís

[Bob Sturgess]

Lluis

Sadly I have Epsom LCD just purchased - will have to live the issue by the sound of

B

[Eric Snodgrass]

Projectors cannot project black, no matter the size of the projector. They project varying levels of light, so there will be some light projected as long as the projector lamp is on and there is no shutter. As you, Bob, have pointed out, varying levels of ambient and/or stage light will make the projector light more or less noticeable. The simple solution is to cover the front of the lens with some material and remove it when you need to see the projected image. It might be an inelegant solution but the audience won't know and won't care.

[Bob Sturgess]

Eric

You've missed the point. Between slides it fine thanks to SCS. It is when I am projecting an image that is smaller than the spread of the projector. The whole area surrounding the image lights up! For instance if a quarter of the screen is occupied by an image. three quarters of the screen are light from projector

[Curt]

Greetings
We had a similar problem with light spill.
Our solution was to create a picture that fills the entire screen of the projector with a large black frame around the actual to be seen image itself.
Regards
Curt