3m Scotchlite tape clone?

[Helge]

I'm looking for a clone of 3m Scotchlite tape (or alternative) that isn't so damn expensive for a whole decent roll.
I'm not looking for kilometers of the stuff just a source that doesn't make it prohibitively expensive to experiment and play with as an amateur.

 

[Mr Bill]

Hi, I don't have any alternatives for you to buy. But depending on what you want to experiment with, let me point out that clothing for cyclists or runners often has reflective strips on it. And the reflective material is similar to what's on highway signs or probably even your license plates. I'm thinking that safety equipment suppliers will probably carry various materials, but maybe not cheap? If you have any fabric supply stores nearby, they may possibly have such materials. Maybe even a bike shop?

Fwiw if you have any specific questions about using such materials i may be able to answer some (I have some experience with front-projection systems).

 

[Helge]

Hi, I don't have any alternatives for you to buy. But depending on what you want to experiment with, let me point out that clothing for cyclists or runners often has reflective strips on it. And the reflective material is similar to what's on highway signs or probably even your license plates. I'm thinking that safety equipment suppliers will probably carry various materials, but maybe not cheap? If you have any fabric supply stores nearby, they may possibly have such materials. Maybe even a bike shop?

Fwiw if you have any specific questions about using such materials i may be able to answer some (I have some experience with front-projection systems).

Old clothes would be too fiddly and have too little material to be useful.

To be more specific I want to replicate something like the Escape from New York “computer graphics” sequence, where John C. Wash wireframes a city model up with Scotch Bright tape.

Some projection screens are made of the stuff.
Anyone know some old defunct brands to look for?
People who know that they have “something special” on their hands generally want special prices.
I’m looking for widows, schools and such, who just want to get rid of stuff.
Therefore brands that are not immediately googleable would probably be good.
Stains and minor tears would be of little concern.
But perhaps retro reflective projection screens are not as efficient as possible to have a greater angle of view?

Retro reflective paint would probably be the next best thing.
Not inexpensive either though. And tough to apply without making a mess, without extensive masking and stenciling.

What specifically are your experiences with front projection on retroreflectors?
I’d be very interested in any stories you could tell.

Front projection would greatly simplify slit-scan like effects integrated into the environment (occlusion and reflecting etc.) for example.

 

[bdial]

An industrial supplier probably has a range of products that may work, for example; https://www.mcmaster.com/reflective-tape/
I don’t know if McMaster ships to the EU, but there are likely similar companies there.
You might also look to motorcycle gear shops.

 

[Mr Bill]

What specifically are your experiences with front projection on retroreflectors?
I’d be very interested in any stories you could tell.

At the outfit where I worked I designed modifications to a specialized flash unit to use in front projection. We put this gear into several portrait studios as a trial. Too much to tell, really, without a lot of fast talking for hours, with a steady supply of beer. The biggest problem was probably getting rid of shadow outlines around the subject - you needed small physical apertures on both the camera and projector lenses, and they had to be aligned almost perfectly.

These screens were very expensive, maybe $3,000 US for a nominal 8x10 foot screen. 20 years ago. They wouldn't work for your purpose, though; they are too directional. You would have to shoot through a beamsplitter with the light source closely aligned otherwise you wouldn't see the effect. This is a result of designing for a very high retroreflective gain factor, on the order of 1,000 times for this type of screen. If you want to be able to see anything even slightly off-axis, I'm thinking on the order of a degree or so, you need a much lower gain factor, maybe less than a hundred or so as a wild guess. The gain factor compares how bright the screen appears compared to a white object.

 

[Helge]

An industrial supplier probably has a range of products that may work, for example; https://www.mcmaster.com/reflective-tape/
I don’t know if McMaster ships to the EU, but there are likely similar companies there.
You might also look to motorcycle gear shops.

Thanks. That is exactly the kind of stuff I'm looking for. I'll try to make an order with them.
I had a very hard time cold googling something similar in the EU.
Anyone who knows something similar over here please chime in!

Experience tells me, that something is probably out there, someplace in the EU. But it's going to be freaking hard to dig up. Once you do though, everyone is going to tell you it was a matter of course and given all along. ;-)

 

[Helge]

At the outfit where I worked I designed modifications to a specialized flash unit to use in front projection. We put this gear into several portrait studios as a trial. Too much to tell, really, without a lot of fast talking for hours, with a steady supply of beer. The biggest problem was probably getting rid of shadow outlines around the subject - you needed small physical apertures on both the camera and projector lenses, and they had to be aligned almost perfectly.

These screens were very expensive, maybe $3,000 US for a nominal 8x10 foot screen. 20 years ago. They wouldn't work for your purpose, though; they are too directional. You would have to shoot through a beamsplitter with the light source closely aligned otherwise you wouldn't see the effect. This is a result of designing for a very high retroreflective gain factor, on the order of 1,000 times for this type of screen. If you want to be able to see anything even slightly off-axis, I'm thinking on the order of a degree or so, you need a much lower gain factor, maybe less than a hundred or so as a wild guess. The gain factor compares how bright the screen appears compared to a white object.

Gain factor is a very useful word to know in this context. Thanks!
Sounds very interesting what you tried to do.

High gain is not necessarily a problem, as I have made a simple homemade beamsplitter with a Cokin holder, exactly for this purpose (and concurrent flashing of film).
What kind of retroreflective material has that kind if gain?
The screens used in Superman and the 2001 Ape man sequence had to have very high gain for the projection to not show up on the talent and sets.
But that kind of material aught to be pretty accessible, even inexpensive today? Wishful thinking?

 

[Mr Bill]

Anyone know some old defunct brands to look for?

Environmental Projection Systems, EPS, in the US made most of the systems. I think a lot of them got put into closets after digital cameras and green-screen software became readily available. If you found such a system you'd want to be sure it came with the beamsplitter (and anti-reflection hood). But it would be so much easier to use the 'standard" retroreflective tape and just photograph it directly, with lights roughly near the camera axis - no beamsplitter needed. A ring light on the lens would work great.

I'm guessing that you want to stay with film, as you haven't mentioned green-screen software. But that gives me another idea for using film. You might be successful if using, for example, a hard-cutting green filter on the lens, combined with a deep green paint in place of the tape. So when you photograph it only the green paint shows up as light-colored. Just an idea, untried by me.

 

[Helge]

Environmental Projection Systems, EPS, in the US made most of the systems. I think a lot of them got put into closets after digital cameras and green-screen software became readily available. If you found such a system you'd want to be sure it came with the beamsplitter (and anti-reflection hood). But it would be so much easier to use the 'standard" retroreflective tape and just photograph it directly, with lights roughly near the camera axis - no beamsplitter needed. A ring light on the lens would work great.

I'm guessing that you want to stay with film, as you haven't mentioned green-screen software. But that gives me another idea for using film. You might be successful if using, for example, a hard-cutting green filter on the lens, combined with a deep green paint in place of the tape. So when you photograph it only the green paint shows up as light-colored. Just an idea, untried by me.

That is actually not a bad idea. Worth trying at least.
Also a way of creating an in camera matte.

But I doubt it would “pop” as much as RR tape, and would require double exposures for colour film.

And yes I’ll stay with film. That’s the fun and the quality of the result I’m looking for.
Otherwise there would be a number if ways to do without RR surfaces

 

[Mr Bill]

But that kind of material aught to be pretty accessible, even inexpensive today? Wishful thinking?

Yep, most likely wishful thinking. The only thing I know of in the US came from 3M, from their tape division as I recall. The widest they could coat was about 3 feet, so the screens were actually assembled by EPS by mounting the strips, slightly overlapped,, onto a heavier plastic base which could be rolled up. You could see the seams on an even-toned background so it was important to project a background scene with some variation, this would completely hide the seams.

They had the beaded material in several different gain factors, but only the highest was used for photography. I'm guessing that this is where the background screens used by Hollywood came from, but probably didn't have quite as high a gain factor as later. The 3M website probably has more data. And as I recall Sidney Ray's book (expensive book), Applied Photographic Optics, gave an explanation including the required refractive index of the beads, etc. I can look it up if you're dying to know.

 

[Mr Bill]

But I doubt it would “pop” as much as RR tape, and would require double exposures for colour film.

I'm not sure. It seems to me that you'd get a light-colored green image on (printed) color film. I DO notice on your sample link a red light on top a building. A green lens filter would block that, but perhaps you could move the green filter onto the lights (maybe Roxcoe gels) then actually use a small red lamp on the building.

Anyway, best of luck however you end up doing it.

 

[Helge]

Yep, most likely wishful thinking. The only thing I know of in the US came from 3M, from their tape division as I recall. The widest they could coat was about 3 feet, so the screens were actually assembled by EPS by mounting the strips, slightly overlapped,, onto a heavier plastic base which could be rolled up. You could see the seams on an even-toned background so it was important to project a background scene with some variation, this would completely hide the seams.

They had the beaded material in several different gain factors, but only the highest was used for photography. I'm guessing that this is where the background screens used by Hollywood came from, but probably didn't have quite as high a gain factor as later. The 3M website probably has more data. And as I recall Sidney Ray's book (expensive book), Applied Photographic Optics, gave an explanation including the required refractive index of the beads, etc. I can look it up if you're dying to know.

Only (and I mean that) if it ain't too much bother. Snap a photo of the page and post it if you can, and I'll be very grateful.
There might be an interesting detail or two.

Interesting that it didn't come in larger sizes. The stuff used on projection screens must have been much lower gain factor.
AFAIK it's all just glass spheres (cubes or three sided mirror pyramids would work too), but of course there is a dozens of ways in which you can optimise the reflection.

I'm not sure. It seems to me that you'd get a light-colored green image on (printed) color film. I DO notice on your sample link a red light on top a building. A green lens filter would block that, but perhaps you could move the green filter onto the lights (maybe Roxcoe gels) then actually use a small red lamp on the building.

Anyway, best of luck however you end up doing it.

Thanks. My idea is to integrate "real world" and "CGI". That's why I'm saying two exposures. So with a real narrow band filter it should be possible.
LEEs Primary Green
https://www.leefilters.com/lighting/colour-details.html#139&filter=cf
for instance seems to have a quite narrow and peaky green. Put that over the flash and in possibly in front of the lens, and you're good. The problem would be to find tape that matched the band as closely as possible.

 

[M Carter]

Are you working towards something similar to Kubrik's "Dawn of Man" sequence from 2001? They used a 3M reflective tape, but they cut it into random shapes to avoid getting hard lines, to make a huge front projection screen. Plenty of articles that detail how they pulled that off on line (sorry if this has been mentioned already!)

 

[AgX]

Environmental Projection Systems, EPS, in the US made most of the systems. I think a lot of them got put into closets after digital cameras and green-screen software became readily available.

"Green-screen" backgrounds can be and still are made in front-projection/retroreflective-screen technology.

 

[Mr Bill]

"Green-screen" backgrounds can be and still are made in front-projection/retroreflective-screen technology.

Hi, this is a thing that I did have the opportunity to look at. Again, we got a system to experiment with. This time for evaluation as a green-screen system, etc., but that's another story.

The "screen" we got was flexible fabric with the tiny beads attached. So you could, for example, drape it over furniture if desired. Now, compared with with the "conventional" front-projection screen material, Scotchlite 7610, it's not in the same league. The gain factor was way less. Just from a fuzzy recollection, and I could be way off, I'd say something on the order of twenty or fifty times less. Under a microscope the reflective beads were pretty sparse (on Scotchlite 7610 the beads completely cover the surface). And... the retroreflective effect seems much less. By this I mean that the returning light is spread over a wider area. Some evidence for this is that retroreflective green-screen can be readily lit up, as seen by the camera, by a ring light around the camera lens. The ring light, an array of colored LEDs (either green or blue, selectable), has a diameter of roughly 3 or 4 inches. So this is about 2 or 3 degrees, more or less, off-axis, and it's working well. Whereas the Scotchlite 7610 wants to be within about one-half degree for best effect.

Anyway, huge difference between the two screens.

 

[Mr Bill]

Are you working towards something similar to Kubrik's "Dawn of Man" sequence from 2001? They used a 3M reflective tape, but they cut it into random shapes to avoid getting hard lines, to make a huge front projection screen. Plenty of articles that detail how they pulled that off on line (sorry if this has been mentioned already!)

Hi, Helge and I had been trading info offline, and yes, Kubrick's system is one he's very familiar with, along with at least a handful of other films.

Fwiw I'd say that the online articles give an overview of the process, enough that people can say, oh, i get it now! But to actually do it, with decent results, is a whole 'nuther animal, as they say.

We ran our homebrew system in several local studios, for probably something around ten or twenty thousand portrait sessions. I explained the workings to a number of people who then "understood" how it works. But when they looked through the camera viewfinder, to see a vivid background, they are always astounded - they go, "Huh?? How does it do THAT!?" And, "why can't I see it out here?" (the screen is a grayish color to everyone else).

 

[Helge]

Hi, Helge and I had been trading info offline, and yes, Kubrick's system is one he's very familiar with, along with at least a handful of other films.

Fwiw I'd say that the online articles give an overview of the process, enough that people can say, oh, i get it now! But to actually do it, with decent results, is a whole 'nuther animal, as they say.

We ran our homebrew system in several local studios, for probably something around ten or twenty thousand portrait sessions. I explained the workings to a number of people who then "understood" how it works. But when they looked through the camera viewfinder, to see a vivid background, they are always astounded - they go, "Huh?? How does it do THAT!?" And, "why can't I see it out here?" (the screen is a grayish color to everyone else).

Yes, Mr Bill was/is very generous with knowledge, experience, documents and some interesting and amusing stories.
A public thank you to him here again.

An example of his help is the realisation that for projecting images (not just flood light), it's important to have the aperture approximately the same size as the taking lens to not have rim shadows.
That would necessitate (probably) a strong light point(ish) source that can take decimation from a low f stop and some decent exposure time.
I have an old Prado 150 projector that might be perfect for (non destructively) putting a one time use PF-1 bulb in.

I actually found some sources, not really of tape (yet) but of very reasonably priced fabric and fabric band. Turns out one of my local sewing and fabric shops has a few choices.
It was, as suspected, a matter of finding the right search words in the right place:
https://www.stofogstil.dk/produkt?Search=refleks
https://www.slojd-detaljer.dk/produkter/?search=refleks bånd
http://reflekstape.dk/shop/frontpage.html

The gain might not be the highest, but good enough for my purpose.
Here is a few sample shots done in the store very simply with an iPhone with and without flash (I have no idea why the last three are rotated):

There is also non stick tape band of the same material, that might even be preferable in some instances if you don't want glue and want to reuse the material.

All of the sticky tape I looked at, had the same or all of the same problems of having segmented hex or square segmentation of the RR coating, being too stiff, and being priced for someone who just needs a meter or two, to cover a bike or railing and have it stick permanently.
Ideally I'd want something like masking tape that is easily ripped and cut.
Might have to just fish a bit around and get the least worst.

Notice the feline eyes "betraying" the effect.

Beam splitter for very high gain and alignment, video tap and repeatability, and ability to zoom and turn was what made the Zoptic system a behemoth. Not what you really need for stills.


Some examples of RR for the luminous effect.