Fake ALR. Is there such a thing? / Are all grey screens ALR?

[Jester1066]

The projector is an Epson EH-TW7300.

Thanks - I'll probably end up going for an Epson - (EH-LS12000B) is looking a likely candidate atm. Just waiting for some inheritance to come through.

 

[Tyler Durden]

Grey Screen

White Screen

 

[Tyler Durden]

I think I prefer the image on the white screen, but you can see my white ceiling is darker with the grey screen in use.

 

[Jester1066]

I still prefer the white screen myself. Which is interesting - as everything I've read suggests if you have a white ceiling an ALR is better. Your non scientific tests do show the grey screen does darken the ceiling, to back this up. So I guess it's doing its job (ie rejecting ambient light).

So both screens have their merits.

 

[Tyler Durden]

Yes. Also I have some calibration to do with the grey screen up.
That should brighten the image.

 

[Jester1066]

Yes. Also I have some calibration to do with the grey screen up.
That should brighten the image.

Looking closer at both your last images. One advantage the grey/ALR has vs the white screen is that it seems that the room as a whole is darker. For example, your AV cabinet is less obvious and the actual screen disappears more against the darker background.

 

[Tyler Durden]

Yes, and the black bars above and below the 21:9 ratio image are much darker.

 

[Jester1066]

Yes, and the black bars above and below the 21:9 ratio image are much darker.

Yep, so (depending on the image brightness) post calibration of the ALR - I might favour it (as giving a more immersive experience) vs the white screen.

To this end, I'll await your findings! Either way it's all very useful info - as my room conditions/colour seem very similar to yours. So many thanks!

 

[Tyler Durden]

I have to admit, I've bought the wrong size ALR so I'll be sending it back whatever happens.
I may decide to order another in the right size!

 

[Jester1066]

I have to admit, I've bought the wrong size ALR so I'll be sending it back whatever happens.
I may decide to order another in the right size!

What size is it you've got then? I can only fit a 110" in my space and it needs to be AT ideally!

 

[Tyler Durden]

I need a 106" but for some reason I forgot this fact and ordered a 120".

 

[Jester1066]

I need a 106" but for some reason I forgot this fact and ordered a 120".

Any reason you can't stick with the 120" - it seems to fit nicely

 

[Rocketrazor]

Be interesting to see what the picture should look like in your post #27. Have you compared it on a TV to see which is nearest? I looked at the grey and thought that looks great, saw the white and thought wow. Yes you cab see the bars more on the white but the picture just looks better to me. This is interesting stuff, though I did read somewhere that one of the obvious pit falls of grey is that you can't get great whites on it. Keep having a play and keep us posted

 

[Eggman]

If you decrease the brightness of the projector does that improve the black end of the spectrum (and improve the white definition)? The ambient light on the ceiling etc obviously looks brighter as more light is being reflected by the white screen, hence the picture looks brighter. If you decrease the brightness of the projector you should decrease the excess ambient light in the room and improve the blacks on the white screen.

 

[alebonau]

I think I prefer the image on the white screen, but you can see my white ceiling is darker with the grey screen in use.

you can lower the scope image down lower on screen it takes it further away from that ceiling and helps immersion so more in eyes view.. and also closer to your speakers ..whcih will only help lock audio more to the image

have you checked the projector output ? make sure its dialled back so only 12-16 FL for SDR and 30FL for HDR.. not need to be pumping excessive lumens on the screen to jsut bounce off

ps the grey screen will have lower gain and hence reflect back less light its why it also looks duller... the whites on the white screen(eg the white clouds) look whiter.. on the grey screen they look grey...ie grey clouds no amount of calibration is going to make the greys white unfortunately oems to have hit the highlights too on the grey screen...

 

[3t3p]

Thought the eye instantly calibrates for white point. When I had my grey screen white was white enough though if you stop and look at it hard I suppose you could see it was off white. The other benefits for me far outweighed this and I don't like an overly bright image searing my retinas anyway (he says with ls12000 on order!).

 

[Tyler Durden]

FYI, I have requested a return and refund.
When I did this they immediately offered me a £115 partial refund to keep the screen which I have rejected (not because it is a bad screen, but more because it's the wrong size! ).
In the future I may well order the right size and spend some more time with the calibration options.

 

[Tyler Durden]

you can lower the scope image down lower on screen it takes it further away from that ceiling and helps immersion so more in eyes view.. and also closer to your speakers ..whcih will only help lock audio more to the image

have you checked the projector output ? make sure its dialled back so only 12-16 FL for SDR and 30FL for HDR.. not need to be pumping excessive lumens on the screen to jsut bounce off

ps the grey screen will have lower gain and hence reflect back less light its why it also looks duller... the whites on the white screen(eg the white clouds) look whiter.. on the grey screen they look grey...ie grey clouds no amount of calibration is going to make the greys white unfortunately oems to have hit the highlights too on the grey screen...

Actually, yes I do have a lens setting for 21.9 that does bring it down level with the bottom of the screen, I just didn't do it for these images.
I'll check the output. Are there recommended screen patterns for this?

 

[alebonau]

Actually, yes I do have a lens setting for 21.9 that does bring it down level with the bottom of the screen, I just didn't do it for these images.
I'll check the output. Are there recommended screen patterns for this?

any white screen ...literally even youtube ... jsut make sure you select the 4k HDR setting to set iris and lamp output for 30FL and select 1080p SDR setting for SDR and 12-16FL

 

[Tyler Durden]

any white screen ...literally even youtube ... jsut make sure you select the 4k HDR setting to set iris and lamp output for 30FL and select 1080p SDR setting for SDR and 12-16FL

Thanks, any advice on a cheap meter?

 

[alebonau]

Thanks, any advice on a cheap meter?

the dr meter one from ebay / amazon a lot of guys rom avs use and its pretty affordable I use the RS electronics ILM meter thats a tad more expensive but has been quite accurate for this kind of thing and always matched up well with more expensive meters eg when pro calibrator came over and said i was spot on for peak luminance using it

 

[kenshingintoki]

FYI, I have requested a return and refund.
When I did this they immediately offered me a £115 partial refund to keep the screen which I have rejected (not because it is a bad screen, but more because it's the wrong size! ).
In the future I may well order the right size and spend some more time with the calibration options.

ALR screens to me create a plasma like image. No bright whites but a nice deep contrasty image. its a trade off.

 

[Peter Parker]

ALR screens that use glass beads reflect light back to the source (retro reflective) - so if you use a torch and walk around with the torch, it will reflect light back to the torch, so you won't be able to see any real drop off like would if you set the torch up in one place (like you would with a projector), and then walked around to see where it was brighter and dimmer. That's also why those screens don't work with UST projectors - most of the light is being reflected back to the projector which is on a table right in front of the screen, and not the audience. Those kinds of screens work for normal set ups because the audience is below the pj so although the reflection is going in the right direction, the audience is rarely right under the pj, so the viewers rarely get the full rated gain. They also tend to have more artefacts like a kind of 'speckle' from the glass beads Other screens with gain that are angular reflective, reflect the light away at the same angle it was received at, so still aren't ideal for USTs but are less problematic as they don't rely on glass beads, and are a bit more forgiving.

The best light meters to use are ones that are photopic as they have a similar response to the human eye. There are some cheap Robin RT24s on ebay from time to time and they are the same as the equivalent Tecpel and Extech meters - same meters just different coloured bodies. I found light meters to be more accurate and reliable than colorimeters for measuring contrast, though more modern, more expensive, more accurate meters may work better. I'd still be inclined to use a dedicated light meter though. Although this discussion is about measuring lumens, just thought I'd mention that if/when measuring contrast, make sure the meter is close enough to the projector lens that you get a god reading for black (not 0.001 as the margin of error there is huge, you want something more like 0.01 or higher in decimal places) and a good reading for white without overloading/oversaturating the meter.

Grey is just white at a lower luminance - when you calibrate a pj, you're calibrating the greyscales and each level of grey is calibrated to D65 - so each level (10%, 20%... 80%, 90%) all have the same balance of RGB. With a (calibrated) grey screen you have to let your eyes adjust to the dimmer level and not compare to the white which will affect your perception. We tend to be attracted to brighter images so if you compare you're probably not going to like the grey screen (assuming it's not so dim that the image really is dull and unappealing).

 

[Vila]

Grey Screen


White Screen

This is a very bright image overall across the frame - typical of the type of thing you see on TV shows.

Find some darker scene's (that are very typical in films) and do some comparisons for yourself.