[ANSWERED] Question about minimizing projector light bleed

TiffTiff

Hello everyone.

Want to do a very simple thing, to project a ring on the wall. Did cut out the ring on the INPUT, the OUTPUT however projects light everywhere. Not the light from the video content but some other light, indicating screen size rectangle. I am using: MacBook Pro Os Sequoia 15.1 and an Epson EB-G5600 (1024x768), Isadora 4.0.2

Seems that I set projector correctly, so it does not mirror the main screen. Does anyone know what am I doing wrong? How can I get only the ring illuminated?

Thanks in advance!

dbini

@tifftiff

that looks like a hardware issue. have you got the brightness setting on your projector turned way up too high? it looks like it is bleaching out the lighter areas of your image and over-saturating the colours, with the added issue of making the black areas into grey.

Skulpture

Factory reset the projector for sure.

DillTheKraut

@tifftiff said:

EB-G5600

This is a very old projector and if I interpret it right, you are projecting 4500 Ansi Lumens onto a small peace of paper. Right?
Therefor this is (probably) the physical limits of the projector. No projector is doing a perfect black. There always is a residual light leaking. Depending on the projectors tech and the general quality of it, it might be more or less. Another factor is the amount of light (lumens) coming out of it. The more powerful, the more 'leaking' light.

Usually on a bigger projection, this isn't an issue. But if you are very close/ zoom the picture very small, all the light coming through the lens is focused on a very small area, getting intensified. This is true for the whole picture, as well as the residual light.

TiffTiff

@dbini thank you for the reply! I actually turned the brightness to the lowest setting

TiffTiff

@dillthekraut thank you for the reply! I am using a piece of paper just to test, later I will move everything and project the image on a wall 6m away from the beamer. How can I reduce the leaking light? The beamer is already on the lowest brightness...

TiffTiff

@skulpture thanks! will try that, hopefully it helps

TiffTiff

@skulpture it did not help unfortunately...

dbini

@tifftiff
I didn't realise this was so small and close. that's going to concentrate your light source on a small area, so it will be too bright at this distance. check it a few metres from a wall - i bet the grey square disappears, unless you are in a completely dark room, where you may be able to see the edges of the projection a bit.

Skulpture

Ah yes - if you are very close then things change such as the brightness, focus and general quality, you can find out more here: https://www.projectorcentral.c...

DillTheKraut

@tifftiff said:

How can I reduce the leaking light?

If the issue comes from the residual light as it is very likely, you probably can't. It is a construction related hardware issue. On modern laser projectors you can stepless adjust the light source intensity. Therefor you could balance between picture brightness and backlight (residual light) intensity.
Conventional light bulbs in old projectors always have the full light power level. You can't lower this with the standard brightness level setting, as this only relates to the video input signals (source) brightness, not the 'backlight' power (Which is kind of the same like the backlight level in some LCD TVs). Though some bigger projectors does have a physical iris for the dynamic brightness feature. On some you can adjust the general light intensity with it.

As I wrote, if you move to the bigger projection, this issue will be less intense there.

dbini

@tifftiff

If you still have an issue with the black background showing up when projecting at full size, the EB-G5600 has Eco Mode, which drops the output down to 3600 Lumens, which may help.

DusX

Another option, since it seems you may have more light than you require, you could change the projection surface. Likely you are looking at a white surface (wall) for projection, but if you make the wall mid grey, it will consume more of the light.

Try your projection test on a piece of black construction paper and compare.

DillTheKraut

@dusx said:

<p>Another option, since it seems you may have more light than you require, you could change the projection surface. Likely you are looking at a white surface (wall) for projection, but if you make the wall mid grey, it will consume more of the light.</p><p>Try your projection test on a piece of black construction paper and compare.</p>

That's a very good suggestion. There are special projection screens which are black on purpose. With a black background, you get a deeper contrast, especially in a surroundings which are not perfectly dark. E.g. with a lot of ambient or even direct light to the screen. A white screen reflects more of the ambient light, which makes the dark part in the projection brighter. With a darker screen you can compensate this. But you might need more power to push the bright parts of the picture.

TiffTiff

@dbini thank you! that's the thing, I will be working in a pitch black space and every light 'leakage' is bad. I have added an analog mapping, without subtracted center circle as it's pretty difficult. But it looks already better this way.

TiffTiff

@skulpture thank you!!!

TiffTiff

@dillthekraut thank you! I have added a physical map and will probably use some kind of gobo or iris in the end

TiffTiff

@dbini thanks! tried eco and it's better!!!

TiffTiff

@dusx thank you! yes, black background helps a lot

dbini

@tifftiff

your physical mask looks good, but you might want to test it over a longer time - as the projector warms up it might soften the glue on the tape, leading to some comedy sagging. 4500 lumens might also warm up the mask quite a lot - be careful you are not creating a fire risk.