Hi all,

I’m trying to set up a DI/RI screen (dual IR LEDs clusters lighting up the screen from about 0.9m below).

I have Rosco Twin White available to me to use with the acrylic but I see no mention of it in the forums only Rosco Grey. I was wondering if anyone had tried using Twin White and were the results good or bad?

Seems to me from Rosco website that it should be OK but it is going to be less suitable in brighter ambient light conditions. It may be more prone to picking up more stray external IR sources as well. However in dark conditions it should be able to draw people in from further away because the screen will appear brighter from a distance.

Question 2: Is it better to adhere the screen underneath or on top?
Question 3: Is diluted PVA glue the best method of adhering the screen particularly if it goes on top?

Thanks in advance from a newbie,

bamalam

Disclaimer - the PVA method took me quite a while to perfect - you may be risking your ROSCO - no responsibility accepted

There’s pro’s and cons of having it on top or underneath.

It would be better to have it on top for two reasons - it’s a great surface for dragging your finger over and also it’s better to have the projection on the top surface rather than 9mm below (or however thick the table top is)

Having it below reduces the glare/reflection from the projector.

PVA glue works really well but it’s got to be applied VERY evenly with almost all of it squeezed out with a squeedgy.

You don’t really need to PVA it if it’s on top.  Just use a squeedgy again (minus the PVA) to flatten it on to the surface.  It will stay in place quite well.

If you are using a squeedgy then keep the top of the Rosco quite damp - makes it a lot easier.

http://nuigroup.com/forums/viewthread/7499/

Paolo,

Thanks for the tips. So that I know how the Rosco will cope I’ll use a glue that allows me to reposition it instead of PVA. I’ve picked up a small can of Bostik Fast-tak which I’ll try. It’s sold as a repositionable glue. I’ll post the the results of my tests. The first test will be on small sample of acrylic that I have before applying it to the main table piece.

In your thread the tip of having the Rosco cut a few mm away from the edge sounds like a good one. The suggestion of avoiding using glue altoghether is another interesting one. It’s given me an idea that I’ll try and I’ll see if I can take a few photos of the results.

bamalam

WAIT!!!!!

The PVA allows hours of time for repositioning.  It also dries almost clear.  I think that Bostik glue is kind of like an contact glue that gives you a bit of time to move it around - VERY STICKY.

If you’ve got to use glue I’d stick to either PVA or buy an optically clear adhesive - if you can find one…

Just to reemphasise - you’ve got to get almost all of the PVA out from under the Rosco or you’ll get patches when it dries

OPTICALLY CLEAR 3M ADHESIVE - http://solutions.3m.com/wps/portal/3M/en_WW/electronics/home/productsandservices/products/TapesAdhesives/OpticallyClearAdhesive/

or

PVOH glue would be good.

It seems that Elmers Gel Glue would do the trick - goes on blue but dries clear - think it’s PVOH

http://www.officedepot.com/a/products/951004/Elmer-s-School-Glue-Gel-4/

The following may melt the Rosco - I really don’t know for sure though…

Clear spray - http://www.hobbymamma.com/clear-adhesive-aerosol-spray-12-fl-oz-pr-16691.html

Last one - you get the general idea

http://www.internet-stationers.co.uk/Shop/istationers_shop/index.asp?deptID=1251&ptype=2

Paolo,

I’ve decided to just put the glue around the edges where the screen projection/touch is not in use which ever glue I use.

In the meantime I’m using the protective white cover on the acrylic to double as my projection screen.

I’ve ended up getting disappointing results for the RI method (hotspots) so I’m now going to go and change the setup to FTIR. This requires the use of black 1mm high plastic strip around the edge of the screen. This is what I’ll stick the screen to if I can get it to stretch out evenly.

bamalam