DIY 2.35 screen construction

[Don Bond]

After deciding to go ahead with the 2.35 project, I picked up some 3/4 in sq Al tubing for the screen frame. Basically, the frame will be 108 x 46 inches, and mounted to the wall on 3 inch brackets. The brackets will support the frame on the inside edge. The outside edges of the frame will be drilled to acommodate screw-in male snaps. The female snap will be part of the screen material. I intend to have a snap every 12 inches.

I will be using BOC for this go-around. My idea is after the frame is mounted to the wall, stretch the BOC around the frame and using small brads thru the drilled out holes to mark the position of the snaps. Then go back and secure the female snaps to the BOC. Theoretically then, mounting the screen to the frame should be a snap. ;)

When finished, total cost for this screen will be about $65.

Don

[CAVX]

[QUOTE=Don Bond]DIY 2.35 screen construction
After deciding to go ahead with the 2.35 project, I picked up some 3/4 in sq Al tubing for the screen frame. Basically, the frame will be 108 x 46 inches, and mounted to the wall on 3 inch brackets. The brackets will support the frame on the inside edge. The outside edges of the frame will be drilled to acommodate screw-in male snaps. The female snap will be part of the screen material. I intend to have a snap every 12 inches.

I will be using BOC for this go-around. My idea is after the frame is mounted to the wall, stretch the BOC around the frame and using small brads thru the drilled out holes to mark the position of the snaps. Then go back and secure the female snaps to the BOC. Theoretically then, mounting the screen to the frame should be a snap.[/QUOTE]

A snap, that's a little bit funny:) 9 feet? That is a big screen. How deep is the room?

When finished, total cost for this screen will be about $65.

Don't you just love DIY sometimes :)

Mark

[Don Bond]

Mark-
If I could, I'd be doing a DIY PJ. :) Nine feet is not that wide. The room is 11.5 x 20 feet deep, where the last seats are (love seat). The projector will be about 18 feet from the screen.

The screen construction is totally experimental, which is the nature of DIY. Instead of doing a frame the tradtional way (wood), I thought I'd give this a try.

Don

[CAVX]

Sounds good. Good luck and I look forward to seeing some snaps (sorry no pun intended that time :))...

Mark

[sstephen]

There is a section of this forum dedicated to DIY screens. You may want to look through it to see if you can get some other ideas. Some interesting paint mixes etc.

[Don Bond]

Yes, you are probably right Scott. But I don't intend to paint the material. Actually, I'm thinking of using an AT material, since I can extend the screen out from the wall 8 inches and place speakers behind the screen. I found some black "Jefferson Linen" material at a local fabric shop that I could possibly use for masking, since it is AT. I suppose they have the same stuff in white.

I may just back off on the snap idea, since it seems like it may be a PITA. Instead, I think I will use some flat Al stock that I can place on the frame and clamp down on the material. This way I can still change it out if I want to.

I may decide to add a "curve". ;)

Don

[Gary Lightfoot]

I used wood to make the frame with a single centerbrace (use 2 if you want to use an AT screen so you don't block the center speaker), and then stretched and stapled some Draper M1300 material over it. I finished it with a slip-on frame that I'd glued black velvet too. It works well and hides any overspill caused by the lens pincushion effect. If I were to make an AT scren I'd have the velvet frame fit onto the front of the screen and hide the wooden frame (it would look different to the rest which didn't have wood behind it).

I used a normal curtain track with black velvet curtains for the side masking.

Gary.

[tvted]

I did essentially the same as Gary except I added a routed backband that allows the material to float above any cross-members and adds strength perpendicular to the screen which reduces warpage.

I skinned it with Vutec BriteWhite 1.5 which can be purchased via AVS through Jason Turk.

ted

[Don Bond]

Thanks for the input guys. Due to the fact I may curve the screen, I will stay with Al for the frame. I think for this go around, I will place the right/left front speakers on each side of the screen, and the center under the screen.

The Al is 0.062 wall, which will flex enough to conform to the brackets I will be using.

Don

[Gary Lightfoot]

Please post some detailed pics etc, in case others would like to make a curved screen too. :)

Thanks.

Gary

[nrighton]

[QUOTE=CAVX]A snap, that's a little bit funny:) 9 feet? That is a big screen. How deep is the room?



Don't you just love DIY sometimes :)

Mark[/QUOTE]


The DAlite screens use snaps for their larger portable frame / screen systems and work quite well.

[Don Bond]

I've contacted Dalite about their screen material with snaps. Basically, they can supply custom screen material with snaps for about $350.00.

But, I decided not to go this route. I may try a variety of screen materials before I settle in on one particular type.

Don

[ifeliciano]

[QUOTE=nrighton]The DAlite screens use snaps for their larger portable frame / screen systems and work quite well.[/QUOTE]

Yes your right, but Dalite Screens aren't made of BOC (Black Out Cloth). For what it's worth, I just built a BOC screen 105" x 45" using upholstery staples into a wood frame. The staples are about 3" apart and the BOC got some tiny tears from the material trying to shrink back to size after streching and stapling.

Also had to re-strech horizontally due to small wrinkles along the top and bottom of the screen.



http://img89.imageshack.us/img89/2843/dscn0804ta3.jpg

[camarillo_cinema]

Still will go with metal frame, but will do BOC with Velcro.

Don

[Sirquack]

I based my screen on Gary's plans....

http://www.reighn.com/theaterscreen.html

[Zinema]

I am also planning to make a 1:2.35 screen - but might want to curve it a little bit.... any ideas how to curve an frame?

[Don Bond]

Zinema-

I plan to bolt my aluminum frame to the wall with L brackets. The brackets will be longer on the ends than in the center. The fabric will then be placed on the frame. This is my approach to curving the screen.

Don

[MichaelCarey]

I'm in the process of making a 2.35(2.37):1 version of my current 16:9 screen. It's made from white cloth backed PVC marine vinyl and is laced onto an aluminum frame which holds it tight and flat, but this also makes it hard (impossible) to curve it smoothly. Hopefully this won't be required.
Without masking, my screen bears a striking resemblance to a trampoline and I have had many questions about the "trampoline on the wall!".
Check out some pics here :-
http://users.on.net/~michaelcarey/pics/screen/
Regards,
Michael.

[cpc]

I made my original 16:9 using 1 x 2's and blackout cloth. My CIH screen is going to be made essentially the same and will be around 113 x 48 inches or possibly as big as 117.5 x 50 inches. Unless somebody can show me a dramatic difference using another screen material and not costing a fortune, my screen will again be made of blackout material.

[tvted]

[QUOTE=cpc]I made my original 16:9 using 1 x 2's and blackout cloth. My CIH screen is going to be made essentially the same and will be around 113 x 48 inches or possibly as big as 117.5 x 50 inches. Unless somebody can show me a dramatic difference using another screen material and not costing a fortune, my screen will again be made of blackout material.[/QUOTE]

At the beginning of the summer I rebuilt my (based on BoC) screen using Vutec BriteWhite 1.5 aquired through AVS. The change is only "dramatic" if viewed side by side with at least equal area to both. People have commented that the image looks different without knowing I changed anything. I certainly would not return to BoC.

ted

[Gary Lightfoot]

I went from BoC to a 1.2 gain material, which was a little whiter and brighter, then later on when I was trying out I used BoC again and then went to a Draper 1.25 gain material (M1300) and the brightness and colour improvements were far more noticable this time round.

That makes me think that the earlier 1.2 material was probably less than that since the improvement was only subtle.

Overall though, BoC has to be the best value unity gain material avialable, since it works well and is tremendous bang for the buck.

Gary

[tvted]

[QUOTE=Gary Lightfoot]
Overall though, BoC has to be the best value unity gain material avialable, since it works well and is tremendous bang for the buck.

Gary[/QUOTE]

Gary,

I agree whole-heartedly that it is a great bang for buck material. I have measured it directly (i.e. reading the screen) with one of the meters I've access to here at work and compared it to 1.0 and other gain material. BoC, from what I've measured is about 0.8 gain.

ted

[Gary Lightfoot]

Hi Ted, thanks for that. That would explain the difference in gain between them all. THe M1300 measured at 1.25 and compared well at the ST130 material which measured at 1.30, so as it was noticably better than the supposed 1.2 material, I can only guess the 1.2 was nearer unity, and the BoC less so.

How did you measure the gain? I have a light meter that I use for measuring contrast, so it can measure screen gain, I just need to adopt a process that works. When I tried it I couldn't get good results form the screen as the angle was neve consistent.

Thanks

Gary

[cpc]

[QUOTE=tvted]At the beginning of the summer I rebuilt my (based on BoC) screen using Vutec BriteWhite 1.5 aquired through AVS. The change is only "dramatic" if viewed side by side with at least equal area to both. People have commented that the image looks different without knowing I changed anything. I certainly would not return to BoC.

ted[/QUOTE]

Interesting. I imagine different projectors work better with different material. Is it safe to say that those of us with the middle ground lcd projectors, the ones just scraping their way into decent contrast and black levels like the Hitachi TX100 and 200 and the Panny 900, Sanyo Z4 etc may not want certain screen materials? Perhaps something with too much gain may be bad?

[tvted]

[QUOTE=Gary Lightfoot]

How did you measure the gain? I have a light meter that I use for measuring contrast, so it can measure screen gain, I just need to adopt a process that works. When I tried it I couldn't get good results form the screen as the angle was neve consistent.

Thanks

Gary[/QUOTE]

You would need a meter that reads the object (reflective) rather than the normal incident type used for PJ calibration. A spot meter from your camera would work. The problem is a source that would be defined as unity gain. I believe this type of source is based on a particular type of lab material that is defined as reference, much like a black body. Its not something that comes to mind without research, but I've read of its existence.

My method is rough but the extrapolation should be sound with respect to relative comparison. With various screen samples of known gain (at least as far as manufacturers' specs) I projected a 100 IRE field and measured the reflective gain coming from the screen sample. I measured each sample at the same place on the screen wall. Using unity gain as the reference it is simple math to determine if the relative "gains" are as speced and then calculate what was coming from the BoC.

Rough, but should be enough for relative comparisons.

ted

[tvted]

[QUOTE=cpc]Interesting. I imagine different projectors work better with different material. Is it safe to say that those of us with the middle ground lcd projectors, the ones just scraping their way into decent contrast and black levels like the Hitachi TX100 and 200 and the Panny 900, Sanyo Z4 etc may not want certain screen materials? Perhaps something with too much gain may be bad?[/QUOTE]

I sit squarely in that group (AE700 - well likely behind) but I run low lumens because I'm filtered for CR/lower blacks. I went to a slight gain material after comparing them to the BoC when my bulb began to dim. I didn't want to remove my filter.

I'm no screen guru, I believe the rules apply to all pjs - 12 to 16 Ft L for 100% stimulus and blacks fall where your On/Off allows. (My preference is 10 but I'm a sub-marine dweller). A grey screen is useful for ambient light rejection, but that is not an issue with my man-cave where everyone is shrouded in black (I'm one of *those*) ;). I considered a High Gain grey but decided that long term a matte surface was preferable, as I expect any device I purchase is likely to be brighter than my poorly 700, and if it is too bright I've got filters. Sorry I'm of no help beyond that.

ted

[Gary Lightfoot]

Hi Ted,

Thnaks again - so did you move the meter or keep it in place and then place the screen material in front of it against a board or something?

Gary

[tvted]

[QUOTE=Gary Lightfoot]Hi Ted,

Thnaks again - so did you move the meter or keep it in place and then place the screen material in front of it against a board or something?

Gary[/QUOTE]

The meter remained in the same location.

With a reflective meter i.e. it is measuring the light reflected *from* the scene rather than an incident meter which is measuring the light source, distance should not be an issue as it is measuring an angel of view. Themeter (http://www.sekonic.com/products/products.asp?ID=5)I used (in its spot function) measures down to 1 degree of arc. All i did was masking tape the screen sample to the BoC in the same place and took meter readings.

ted

[Gary Lightfoot]

What meter are you using? I think mine is probably an incidence meter.

Thanks

[tvted]

[QUOTE=Gary Lightfoot]What meter are you using? I think mine is probably an incidence meter.

Thanks[/QUOTE]

Oops! Sorry, poor formatting on my part buried the link to the meter I was referring to, so here is the link in its full glory. http://www.sekonic.com/products/products.asp?ID=5

Any meter which measures a light source (pj lamp, sun et al) is of the Incident variety. Any which measure the subjects illuminated (screen, semi-clothed women {depending on your propensities}) would be Reflective. The advantage of this meter is that it is both. The "knobby" protrusions on the sides are actually a lens/viewfinder which is used when sighting the object to be measured in reflective mode.It suits our needs in Studio setups and I borrow it on occassion. I'm a broadcast tv studio grunt/gnome, or yard ape if you prefer, who pushes buttons (equipment and people's) for a living.

ted