What makes a good screen

atsnom · 30th October 2005, 01:06 PM

I now have a half working projector together (OHP & Goodmans portable dvd player/screen)

I wish to make a screen as my wall is a bit mucky and im sure it blurs the light a little.

I have been reading threads for days now with 100's of sujestions but what I cant seem to find information on is WHAT makes whatever your using a good screen. What should I look for in the matirial I use, Its all good telling me that the ikea blind you use works very well, but i need to know WHY it works well.

Please help me as I dont wish to make a poor quality screen

pepe303 · 30th October 2005, 02:00 PM

This "screen" from Ikea works well, because you can roll it out when not in use. Other than that it's not a bit better, then a wall painted with good, white matt paint. And this "screeen" soon will become weavy. If you can paint the wall, I would do it (as I actually did). Just choose really white, good paint (Flugger, Dulux, etc. good brands, not just cheap "white ceiling paint", and ask for a pure white one)

Regards

atsnom · 30th October 2005, 02:17 PM

I have read many posts saying exactly the same thing. its not what i need

This thread is here for people to explain WHY I should use extra white paint or WHY blackout cloth or whatever.

I need to know WHY they are good or bad.

What has X got over Y that makes it better ???

So to ask again CLEARLY........

What is it that makes a good screen and WHY. what is it that makes the picture brighter & clearer.

I dont want lists of things you "can" use for a screen, i want to know WHAT MAKES A GOOD SCREEN AND WHY

dnsey · 30th October 2005, 03:47 PM

That depends upon your application!
Very generally, the more 'directional' the screen surface, the brighter the image, but the narrower the viewing angle.
I don't really know why people mess around with 'substitute' materials (except for the sake of experimenting), when proper commercial material is available at a reasonable price. If you want an image up to 60" square, you may well be able to obtain a second-hand screen for nothing.
My preference is for the beaded type, as it has high gain, albeit a fairly narrow viewing angle - fine in my setup, but your mileage may vary.

atsnom · 31st October 2005, 06:54 PM

GAIN ???

Reading more posts i come across the word GAIN,

What does this mean.

And how can i tell what "GAIN" my materal or paint has ??

dnsey · 31st October 2005, 06:58 PM

It's a misnomer really - a screen can't achieve any real gain! It refers to the proportion of incident light which is reflected towards the viewer - its efficiency, if you like.
Commercial screen materials include the gain in their specification. In the case of other materials, it's a case of measuring or comparing.

dnsey · 31st October 2005, 07:03 PM

Actually, thinking about my last reply, I suppose actual gain IS theoreically possible. If a fluorescent finish were used in combination with a source rich in UV to excite it, it would actually 'shine'! (The technique was used by a number of 'old masters' to make their paintings luminous).
Anyone tried it (I know the trouble with UV and LCDs would't help)?

politicorific · 4th November 2005, 05:35 AM

Everyone keeps talking about blackout cloth. Jo Ann Fabrics has it cheap as long as you want in 1 dimension, but its only 54" tall. People talk about stretching it out to make a smooth screen, but surely it won't stretch out to double its original size. The largest you should be able to get is like 1.333333 times that correct? Around 70" for 4:3 screen.

Where can one buy blackout cloth which is taller?

Guy Grotke · 6th November 2005, 08:13 AM

Lots of discussion threads about various screen materials at:

http://www.avsforum.com/avs-vb/forumdisplay.php?f=23

But beware: Some very exotic screens and materials (ie. painted mirrors, etc.) are touted as having "high gain", relative to a flat white surface. Some curved metallic screen makers claim a gain of 8 or higher!

I did some experiments with various paints, etc. and I have a real LUX meter. I found that my LUX meter reads about 100 LUX facing the projector (against the screen surface), and reads about 70 LUX facing the screen from 1 foot away. So flat white paint reflects about 70% of the projected light with perfect viewing from all angles. You could only get about a 30% improvement with a perfect mirror surface. So how can you get 8 times more light?

One of the very best surfaces I found was unpainted wallboard mud skimmed over the wall surface (to get rid of the texture) and then sanded flat and smooth.

Mikey p · 6th November 2005, 08:28 AM

Quote:

Originally posted by politicorific
....Where can one buy blackout cloth which is taller?

Lumenlab has it in 110 inch. https://secure.lumenlab.com/shop/group.php?id=5

30th October 2005, 01:06 PM	#1
atsnom diyAudio Member Join Date: Aug 2005	What makes a good screen I now have a half working projector together (OHP & Goodmans portable dvd player/screen) I wish to make a screen as my wall is a bit mucky and im sure it blurs the light a little. I have been reading threads for days now with 100's of sujestions but what I cant seem to find information on is WHAT makes whatever your using a good screen. What should I look for in the matirial I use, Its all good telling me that the ikea blind you use works very well, but i need to know WHY it works well. Please help me as I dont wish to make a poor quality screen

6th November 2005, 08:13 AM	#9
Guy Grotke diyAudio Member Join Date: Sep 2004 Location: Vista, CA	gain = mostly hogwash! Lots of discussion threads about various screen materials at: http://www.avsforum.com/avs-vb/forumdisplay.php?f=23 But beware: Some very exotic screens and materials (ie. painted mirrors, etc.) are touted as having "high gain", relative to a flat white surface. Some curved metallic screen makers claim a gain of 8 or higher! I did some experiments with various paints, etc. and I have a real LUX meter. I found that my LUX meter reads about 100 LUX facing the projector (against the screen surface), and reads about 70 LUX facing the screen from 1 foot away. So flat white paint reflects about 70% of the projected light with perfect viewing from all angles. You could only get about a 30% improvement with a perfect mirror surface. So how can you get 8 times more light? One of the very best surfaces I found was unpainted wallboard mud skimmed over the wall surface (to get rid of the texture) and then sanded flat and smooth.

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30th October 2005, 02:00 PM	#2
pepe303 diyAudio Member Join Date: Apr 2005 Location: Poland	This "screen" from Ikea works well, because you can roll it out when not in use. Other than that it's not a bit better, then a wall painted with good, white matt paint. And this "screeen" soon will become weavy. If you can paint the wall, I would do it (as I actually did). Just choose really white, good paint (Flugger, Dulux, etc. good brands, not just cheap "white ceiling paint", and ask for a pure white one) Regards

30th October 2005, 02:17 PM	#3
atsnom diyAudio Member Join Date: Aug 2005	I have read many posts saying exactly the same thing. its not what i need This thread is here for people to explain WHY I should use extra white paint or WHY blackout cloth or whatever. I need to know WHY they are good or bad. What has X got over Y that makes it better ??? So to ask again CLEARLY........ What is it that makes a good screen and WHY. what is it that makes the picture brighter & clearer. I dont want lists of things you "can" use for a screen, i want to know WHAT MAKES A GOOD SCREEN AND WHY

30th October 2005, 03:47 PM	#4
dnsey diyAudio Member Join Date: Mar 2004 Location: Shropshire, England	That depends upon your application! Very generally, the more 'directional' the screen surface, the brighter the image, but the narrower the viewing angle. I don't really know why people mess around with 'substitute' materials (except for the sake of experimenting), when proper commercial material is available at a reasonable price. If you want an image up to 60" square, you may well be able to obtain a second-hand screen for nothing. My preference is for the beaded type, as it has high gain, albeit a fairly narrow viewing angle - fine in my setup, but your mileage may vary.

31st October 2005, 06:54 PM	#5
atsnom diyAudio Member Join Date: Aug 2005	GAIN ??? Reading more posts i come across the word GAIN, What does this mean. And how can i tell what "GAIN" my materal or paint has ??

31st October 2005, 06:58 PM	#6
dnsey diyAudio Member Join Date: Mar 2004 Location: Shropshire, England	It's a misnomer really - a screen can't achieve any real gain! It refers to the proportion of incident light which is reflected towards the viewer - its efficiency, if you like. Commercial screen materials include the gain in their specification. In the case of other materials, it's a case of measuring or comparing.

31st October 2005, 07:03 PM	#7
dnsey diyAudio Member Join Date: Mar 2004 Location: Shropshire, England	Actually, thinking about my last reply, I suppose actual gain IS theoreically possible. If a fluorescent finish were used in combination with a source rich in UV to excite it, it would actually 'shine'! (The technique was used by a number of 'old masters' to make their paintings luminous). Anyone tried it (I know the trouble with UV and LCDs would't help)?

4th November 2005, 05:35 AM	#8
politicorific Account disabled at member's request Join Date: Aug 2005	Everyone keeps talking about blackout cloth. Jo Ann Fabrics has it cheap as long as you want in 1 dimension, but its only 54" tall. People talk about stretching it out to make a smooth screen, but surely it won't stretch out to double its original size. The largest you should be able to get is like 1.333333 times that correct? Around 70" for 4:3 screen. Where can one buy blackout cloth which is taller?

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