Quantcast

D.I.Y. 3-Way Masking - (will be useful for most fixed frame screens)

Pecker

Distinguished Member
Having an unusual 2.00:1 ratio screen, I need 4-way masking. Well, 3-way masking - films which are 'too narrow' for the screen need a mask at each side, but films which are not tall enough ('scope) only really need masking at the bottom, with the image racked up to the top, rather than keeping the image in the middle and masking both top and bottom.

If that's not clear now, hopefully it will be once I've posted pics.

I've decided to make the masks from polystyrene sheets covered with self-adhesive velvet.

Okay, the new masking is very much in 'testing' mode at the moment.

I made the 'masks' with a lot of help from a mate (for clarity, he did all the work) on Friday.

I only bought a 1m x 45cm roll of the self adhesive velvet yesterday, and I have four pieces of masking. Clearly that's not enough, but I wanted to experiment.

My screen is 2.00:1 ratio at 280cm x 140cm. So 1.85:1 is 259 x 140, whilst 2.40:1 is 280 x 117. That means I need two masks for each side, each 10.5 x 140, and a big mask for the bottom of 280 x 23.

As the polystyrene can't be bought in sheets 280cm long I've had to make two pieces of 140 x 23 each.

Yesterday I covered one of the side masks completely and half of the other with the 1m x 45cm roll I'd bought. This velvet will be coming off, and replaced. I just wanted to try several techniques.

Pics and links later.

But the one thing clear from watching a 1.85:1 film last night is that the masks 'work', in that in use they created a solid black border for the film, and were indistinguishable from my fixed frame screen's black velvet borders.

They also stay in place.

Steve W
 
Last edited:

Pecker

Distinguished Member
Here's the polystyrene boards I'm using:

http://www.wickes.co.uk/Wickes-25mm-General-Purpose-Polystyrene-600x2400mm/p/210801

If you want a sample of the velvet, you can get it from Wilco:

http://www.wilko.com/sticky-back-plastic/d-c-fix-original-deco-self-adhesive-film-velour-black-348-0005/invt/0309578

Most people will want more than 1m. It's not that difficult to match two pieces up - I did this when experimenting yesterday, and I couldn't see the join - but one piece is nicest.

If you buy it from this link at Amazon they'll send it in multiples of 1m, all as one long roll, up to 15m.

If that's not long enough you probably need to consult a proper cinema suppliers. :D

Anyway, here's the link:

http://www.amazon.co.uk/gp/product/B00BQY3GNW?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00

It's £5 per meter, same as at Wilco, but you have to pay for postage. This is progressively cheaper the more you buy, so including postage it costs:

1m £8.57
2m £14.15 (£7.08/m)
3m £19.73 (£6.58/m)
5m £32.94 (£6.58/m)

I've ordered 5m. I've also bought some strong, black duct tape for £5. I needed two polystyrene boards, so that cost me £13.30.

The only other thing I needed was a chunky stapler and some staples, but I had those already.

Total cost just over £50.

Steve W
 

KelvinS1965

Distinguished Member
Good project Steve.

I use simple black velvet strips that hang from cup hooks under my screen pelmet and they make 1.85:1 content look much better with a jet black frame around it. They are a bit 'wavy' so I've been meaning to get something more solid to wrap the material round. Did you staple the material to the back of the polystyrene? I'm wondering if I could do the same with my velvet strips.
 

Pecker

Distinguished Member
Good project Steve.

I use simple black velvet strips that hang from cup hooks under my screen pelmet and they make 1.85:1 content look much better with a jet black frame around it. They are a bit 'wavy' so I've been meaning to get something more solid to wrap the material round. Did you staple the material to the back of the polystyrene? I'm wondering if I could do the same with my velvet strips.
Wrap - definitely wrap.

I'll post more on this when I post pics of me applying the velvet to the polystyrene, which should be on Wednesday or so.

Possibly a few comments a little later today.

Steve W
 

Pecker

Distinguished Member
Making the boards.

This is a full size sheet being measured:

01 Measuring.jpg


Then roughly cut with a band saw, to about an inch too big.

02 Band Saw.jpg


Now, when I've cut polystyrene at home it's crumbled horribly, producing nothing even close to a straight edge - totally unusable.

So our plan was to rough cut with the band saw and finish with a hot wire cutter, which we did for the first panel:

03 Hot Wire Cutter.jpg


This gave a perfect edge, but the band saw wasn't too bad (you can probably see that). So, as the hot wire cutter was so fiddly, we just used the band saw to finish everything else off, and here are the finished panels:

04 Finished.jpg


Steve W
 

Pecker

Distinguished Member
Here's the screen without any masking:

05 Screen Without Masking.jpg


The idea is to simply squeeze the panels in place, held there by friction fit.

Here are the side panels fitted in:

06 Sides in Place.jpg


I was worried about the bottom two. I'll probably be attaching them together, but my first thought was that the 'squeeze', unless it was millimetre perfect, would just pop the panels out.

So I wondered if they'd just sit there, and subsequently tried one on its own:

07 One at the Bottom.jpg


Excellent. Now both:

08 Both at the Bottom.jpg


Bonza!

Steve W
 

Pecker

Distinguished Member
Okay, wrapping.

First one I experimented with, I cut the velvet to 15.5cm. The panel is 10.5cm wide and 2.5cm thick, so that just covered the front and both sides, nothing round the back.

Not a good idea. It was okay, but lining such a long piece up correctly was near impossible. Also the self-adhesive glue needs to be held in place whilst it dries, which is just not possible for such a big piece.

Sure enough, it wasn't dead straight, and it started to peel.

So, plan two was to add another 4cm or so, so it wraps round the back by 2cm on each side.

Then staple in place.

Then use duct tape to hold in place, and also to cover the staples, which might otherwise damage the screen.

This worked perfectly on the piece I tried as an experiment.

I'll post pics when I do the real thing later in the week.

Steve W
 

Pecker

Distinguished Member
It looks good but how long will polystyrene hold up to being regularly handled?
It's some thing I've been wondering myself.

I'll let you know.

It actually feels very sturdy, and being wrapped in velvet should help. First place to go will be the ends of the side masks, as it's such a tight fit.

Steve W
 

Pecker

Distinguished Member
Managed to get a lot done last night.

I've managed to complete the side masks, but I still have to finish the bottom, so this will just focus on the sides.

Firstly, attaching the velvet.

I've bought a 5m roll:

01 Velvet Roll.jpg



Cut off a 140cm length, which I then cut in two, down the middle:

02 Cut Down.jpg


Peel off the backing, stick it to the polystyrene, staple it in place:

03 Staple On.jpg


Close up of the staples:

04 Close Up.jpg


More in a moment.

Steve W
 

Pecker

Distinguished Member
Okay, my Sony projector has a test pattern which shows up various ratios.

The outside edges of the 16:9 image are marked by a solid double line. With a 16:9 screen the idea is to ensure you can see all of the inside line and non of the outer.

Just inside these at the top and bottom is a broken line denoting 1.85:1. Further in from the top and bottom are broken lines denoting 2.35:1.

Here's the image on my 2.00:1 screen, without masking, set for 1.85:1. You'll see that the outer 1.85:1 broken lines are just off image, being projected on to the fixed frame's black velvet top and bottom borders.

The double line for the left & right edges of the 16:9 image are on show.

Because this is 2.00:1 screen you can clearly see a gap between these double lines and the left and right velvet borders of the fixed frame screen:

01 1.85 pattern no masking.jpg


Now with the masking in place:

02 1.85 pattern masked.jpg


You'll see the outer solid line has disappeared, whilst the inner line is completely visible on both sides.

Meanwhile the 'dark grey' bars on the left and right are now gone.

How is it with real world material?

Okay, a paused image from The Purple Rose of Cairo (1.85:1) without the masking in place:

03 TPROC no masking.jpg


Grey bars visible.

With masking:

04 TPROC masked.jpg


It's a shame I've not managed to do the 2.40:1 mask yet, as the left and right grey bars with 1.85:1 material is slightly less of an issue for me than the grey bar at the bottom for 'scope though, to be totally honest, neither is a huge problem for me.

But I need to stick the two pieces together, and I'm still deciding on exactly how I'm going to proceed with this.

I should be completing this tomorrow night.

More pics then.

Please feel free to ask any questions or make any observations.

Steve W
 
Last edited:

geogan

Well-known Member
Interesting. Looks like the amazon link is gone though "Currently unavailable.
We don't know when or if this item will be back in stock."

I'm trying to figure out a way to do masking myself some day. Probably only horizontal for now on the 2.40:1 screen when viewing 16:9 stuff.

By right the screen should be about less than 16:9 height and have 2.40:1 material at full width (with top/bottom masking) and then have 16:9 material at a smaller size (masking all sides) so the 16:9 and 2.40:1 surface areas are the same or similar. I don't like it when the 16:9 image is way bigger than the 2.40:1 stuff on a 16:9 screen. Just makes the 2.40:1 look like a normal TV in letterbox mode. The 16:9 mode needs to be made smaller so actual white area behind masks should be around 16:6 proportion.

Trouble is would need a motorised and memory PJ for this setup and as you know the manufacturers have motorised/memory as an absolute premium feature on their PJs (how much more is the Sony VPL500 over the VPL300 just for the memory slots about £4k? - ridiculous!)
 

Pecker

Distinguished Member
Interesting. Looks like the amazon link is gone though "Currently unavailable.
We don't know when or if this item will be back in stock."
EDIT - NOW BACK IN STOCK AT AMAZON.

When I placed my order it was for 5m, and they were down to 8 left, so someone else has bought the last 3m.

I suspect they'll get it back in stock.

Otherwise you have a few options.

Get it from here at Amazon UK, but it's double the price (free P&P, though):

d-c-fix® Sticky Back Plastic (self adhesive vinyl film) Velours Black 45cm x 1m (ORDER PER METRE) 205-1719: Amazon.co.uk: Kitchen & Home

Or, buy it from Wilco. Unfortunately, they only do 45cm x 100cm. Depending on the size and shape of your project this may not be a problem, and you may not have trouble making sure the edges are level with each other.

Finally, try and find somewhere else that does it on a longer roll.

By the way, when they have it in stock, the Amazon link I originally posted to was for a company called Vinyl Depot. They have a website and contact phone number here, so maybe you could just give 'em a ring to see what's happening.

Vinyl Depot

Steve W
 
Last edited:

Pecker

Distinguished Member
I'm trying to figure out a way to do masking myself some day. Probably only horizontal for now on the 2.40:1 screen when viewing 16:9 stuff.

By right the screen should be about less than 16:9 height and have 2.40:1 material at full width (with top/bottom masking) and then have 16:9 material at a smaller size (masking all sides) so the 16:9 and 2.40:1 surface areas are the same or similar.
That's what my screen is - 2.00:1 CIA (constant image area).

2.40:1 is wider, but 1.85:1 is a little taller. You can swap between them and never feel you're watching a smaller presentation.

To be fair 'true' CIA is 2.05:1, but who's counting?

As for lens memory - I don't mind adjusting zoom, focus and lens shift. It's a little bit of a pain, but it gives me something to do.

Steve W
 

chienmetallique

Active Member
Okay, my Sony projector has a test pattern which shows up various ratios.

The outside edges of the 16:9 image are marked by a solid double line. With a 16:9 screen the idea is to ensure you can see all of the inside line and non of the outer.

Just inside these at the top and bottom is a broken line denoting 1.85:1. Further in from the top and bottom are broken lines denoting 2.35:1.

Here's the image on my 2.00:1 screen, without masking, set for 1.85:1. You'll see that the outer 1.85:1 broken lines are just off image, being projected on to the fixed frame's black velvet top and bottom borders.

The double line for the left & right edges of the 16:9 image are on show.

Because this is 2.00:1 screen you can clearly see a gap between these double lines and the left and right velvet borders of the fixed frame screen:

View attachment 553908

Now with the masking in place:

View attachment 553910

You'll see the outer solid line has disappeared, whilst the inner line is completely visible on both sides.

Meanwhile the 'dark grey' bars on the left and right are now gone.

How is it with real world material?

Okay, a paused image from The Purple Rose of Cairo (1.85:1) without the masking in place:

View attachment 553916

Grey bars visible.

With masking:

View attachment 553917

It's a shame I've not managed to do the 2.40:1 mask yet, as the left and right grey bars with 1.85:1 material is slightly less of an issue for me than the grey bar at the bottom for 'scope though, to be totally honest, neither is a huge problem for me.

But I need to stick the two pieces together, and I'm still deciding on exactly how I'm going to proceed with this.

I should be completing this tomorrow night.

More pics then.

Please feel free to ask any questions or make any observations.

Steve W
Surely Heath Robinson style cuts of a metal coat hanger can help to connect the 2 bits?

Edit: afterthought, or a duct tape rear hinge.
 

Pecker

Distinguished Member
Surely Heath Robinson style cuts of a metal coat hanger can help to connect the 2 bits?

Edit: afterthought, or a duct tape rear hinge.
I'm going to initially use PVA Wood Glue (on the two surfaces which are to be joined).

Then staples (with one prong of the staple on one piece of polystyrene and the second on the other).

Then masking tape (which is very thin and will wrap right round without causing a bump in the velvet).

Then Duct tape (but only along front and back, not on the surface which will be the edge of the masking next to the screen).

Then one sheet of the self-adhesive velour material, which will hopefully hold the lot together.

Pics will follow, hopefully tonight.

Steve W
 

geogan

Well-known Member
That's what my screen is - 2.00:1 CIA (constant image area).

2.40:1 is wider, but 1.85:1 is a little taller. You can swap between them and never feel you're watching a smaller presentation.

To be fair 'true' CIA is 2.05:1, but who's counting?

As for lens memory - I don't mind adjusting zoom, focus and lens shift. It's a little bit of a pain, but it gives me something to do.

Steve W
Oh I didn't realise there was such a thing as CIA screens! Can you buy these commercially? I thought they only sold 2.40:1 or 16:9 screens and then the CIH (horizontal masking) or CIW (vertical masking) or both options on top of these basic screen sizes.

Yes I did some calculations there yesterday and found exactly that - in order for the 2.40:1 and 16:9 surface areas to be equal, the width should be same as 2.40:1 and then new height should be in proportion 2.05:1. See this image I created to clarify things in my head... have you any suggestions of improvements? Labels wrong? Anything I could add?

screen-dimensions.png
 
Last edited:

geogan

Well-known Member
If only we could build something as slick as these commercial 4-way masking systems ourselves instead of paying the gigantic prices they ask for decent screen sizes...

pro-mask.jpg
 

Pecker

Distinguished Member
If only we could build something as slick as these commercial 4-way masking systems ourselves instead of paying the gigantic prices they ask for decent screen sizes...

View attachment 554199
Aye, this is exactly why I went down the DIY route.

One of the US manufacturers makes friction fit side panels for their 2.40:1 screens, but they're expensive, and only made to the size of the off-the-shelf screen sizes in their range.

Putting them in and out is a bit of a faff, but it's really not the end of the world.

BTW, if you haven't checked it out already, there are more pics and comments about my screen in my Home Cinema Room thread:

Home Cinema Number Four - The Build Diary | AVForums

See particularly posts 39 and 42-47.

Steve W
 
Last edited:

Pecker

Distinguished Member
Okay, firstly I used PVA wood glue to stick the two pieces together, then I stapled them, then I covered with duct tape, wrapped right round.

01 Duct Tape together.jpg


Then I duct taped over that from side-to-side.

02 Duct Tape sideways.jpg


Then I laid the panel on the roll of velour and cut it.

03 Lay polystyrene on velour.jpg


Looks wonky as it's one of those panoramic pics.

Then I took the backing off the velour, wrapped it, and stapled it in place.

04 Staple Velour.jpg


I then covered the staples with duct tape, as on the previous panels.

More in a mo.

Steve W
 

Pecker

Distinguished Member
Here's the pattern zoomed to 1.85:1 height:

01 Pattern at 1.85.jpg


Note the dotted lines indicating 'scope.

Now zoomed out so the outer green lines disappear off the right and left sides, whilst the inner green lines stay visible. Then the image shifted up so the top dotted line just disappears off the top of the upper border.

02 Pattern zoomed to scope no masking.jpg


The lower dotted green line (the one floating on its own, not the one just above the two solid green lines) marks the bottom of the 'scope image.

And now with the new lower masking in place.

03 Pattern zoomed to scope and masked.jpg


More in a mo.

Steve W
 

Pecker

Distinguished Member
Finally, another great advantage of a 2.00:1 screen. In use with subtitles.

Here's a 'scope film with subtitles and subs in the lower black bar, no masking.

01 Subs no lower mask.jpg


If I'd has a 'scope-shaped screen, the subs would be almost invisible on the lower border.

02 Subs on lower mask.jpg


You can just read them if you look carefully.

You can shift the subtitles up into the picture area (I have done this with my Oppo), but with shots like the one above as an example, the white text of "...young woman." becomes lost on the white shirt - still visible, but more difficult/less comfortable and less easy to read as quickly.

Steve W
 
Last edited:

Trending threads

Latest News

Disney developing AI based video compression
  • By Andy Bassett
  • Published
Vizio announces Disney+ available on SmartCast TVs
  • By Andy Bassett
  • Published
Audio-Technica reveals Kokutan and Asada Zakura headphones
  • By Andy Bassett
  • Published
Sky announces combined Sky Sports and BT Sport packages
  • By Andy Bassett
  • Published
Qobuz drops MP3s and introduces Studio Premier Plan
  • By Andy Bassett
  • Published
Top Bottom