JVC X3 grey screen 0.8 gain

[Sithuk]

I have used a Panasonic PT AX100 with a Draper Luma 106" grey screen and been highly satisfied with the results for years.

I have recently bought a JVC X3 for no reason other than wanting to try an upgrade. The picture I get with the AX100 and the grey screen still pleasantly surprises me. While I wait on delivery of the X3 I have been reading up on the possible brightness issues with the X3 and a screen with 0.8 gain. I only intend to watch 2D movies. The projector lens will be approx 4.2m from the screen. Projectorcentral's projection calc tells me that I am predicted to achieve 12ftL screen brightness.

I read that I need to lower the aperture setting on the X3 to achieve the higher contrast levels, and that conversely a grey screen is likely to require a higher aperture setting to achieve a 12ftL screen brightness.

Should I really be looking to change to a matt white screen? Does anyone have any experience they would like to share of using a DILA projector with a grey screen?

My viewing environment is a light controlled living room (all lights off, black out curtains, watch movies mainly at night).

All advice appreciated.

 

[Peter Parker]

Do you know what fL you're currently getting? Quite often people have no idea what they're really getting and it can be a lot lower than they think. Once when I was doing a calibration for someone, I discovered they were only getting 3fL before taking into account the screen gain, so maybe 4fL at best, and it looked fine in their dark decor light controlled room.

I would wait until you get the pj and judge for yourself - you may find it looks better than you expected.

If you're not sure how it would compare to a white screen, you could experiment with a piece of white A4 or A3 held onto your grey screen, or get a sample of screen material to compare. Try not to concentrate on the brightness too much and see how the black levels and intra image contrast compare - we're usually drawn to brighter images over all else until you start to look for other things.

If you have light coloured walls and ceiling, a grey screen may still be your best choice, even if you have to open the JVC iris up to get an image brightness you prefer, but you'll still have a lot more on/off contrast than the Pany.

Gary

 

[Sithuk]

Hi Gary,

I agree that the first step will be measuring the light levels with a light meter. I plan to measure the light levels for the AX100, then do the same for the X3 soon. I've never measured the light levels before so I am looking forward to finding out what I am actually getting.

I have approached my current screen manufacturer to try and get a free sample of matt white gain 1.0 material. It is not clear whether I will get one but if not I can try the A3 paper approach you suggest.

The point about the wall and ceiling colours in the room is a valid one. I have cream/white coloured walls and ceiling. I was aware when I originally went with a grey screen that it would help minimise room reflection effects. I recall that the reflections from the room could act to reduce the perceived contrast of the image?

I mainly watch with all lights turned off and black out curtains pulled, so I'm not sure how necessary the grey screen is to minimise room reflection effects. Would you generally recommend a grey screen for such an environment, provided of course that the projector can achieve an acceptable ftL reading with the low gain?

Sithuk

 

[Peter Parker]

You're right - reflections from walls and ceilings allow light from the brighter parts of the image to bounce back and onto any darker parts, and that reduces the intra image (ANSI) contrast. Grey screens help to reduce the effect.

Like most things, there are pros and cons. You have to balance out the pros and cons of white vs grey and decide which image you prefer overall. Even when a grey screen may theoretically be the best choice, some people prefer to have the brighter image a white screen gives over the darker and potentially more detailed image a grey screen may provide.

Yes, I would usually recommend a grey screen for a light decor room or one with ambient, but ideally you need to see a demo of both under the same conditions to decide which is the right one for you.

Gary