Properties of Gel

[Jankers]

Hey, quick question here:

Would regular gel be considered a plastic? I ask because I need to find a proper glue to adhere gel to a high temperature metal, in a situation that hot glue is not appropriate for.


Cheers!

James

[JD]

Modern "gel" is plastic (except diachronics), however some gels have the pigment on the outside as a coating, others are impregnated. Because of this it may not react to glue the way you would hope.

[Jankers]

Thank you kindly

[Footer]

Gel is 2 polyester layers with a color additive in between. Keith will be here shortly I would assume.

[Kelite]

Apollo and Lee gel are double coated polyester for color consistancy, while Rosco and GAM are dyed polyester. The Lee HT consists of polycarbonate material, which has a higher resistance to warping and color migration.


(Edit- Wow Footer, you know when I sit down and open the 'Booth, now don't you?!)

[stantonsound]

ok....I love Apollo gel (and most Apollo products - I use scrollers, rotators, gel, gobos, and more), but recently needed a few sheets that day and the only ones in town that were in stock were Rosco. I bought 8 sheets of this nice purple for use on S4 pars and put them in place. It was a conference at the convention center and the pars were used to uplight fabric columns. After about 2 hours, I got called from the interior decorator that had been hired to design the fabric, flowers, and decorative lighting. She said that the lights weren't purple anymore. I inspected the gels, and they had completely washed out. There was a hint of purple at the edges, but no color at all in the middle. It was not burned or melted, just no color.

Our theory is that this was old gel. The one shop in town that stocks gel has at least 20 of every color that Rosco makes, so it is possible it has been sitting there for years. Is this possible?

[icewolf08]

There are many reasons you could have lost your color. If you were using the S4 PAR EA fixtures, and they were being used as up-light, all the heat from the lamp and the IR and UV radiation were passing through the gel. You would have nearly 100% of the gel damaging heat and radiation hitting the gel. The S4 PAR MCM would have removed some of the radiation from the light and may have saved you some gel, but since heat rises, you would still be directing the rest through the gel. Also, if you picked a "nice" purple, it was probably very saturate, with a low transmission rate, so the chances of it burning through are greatly increased, especially because you probably ran the lights at very near to full intensity.

I doubt it was a case of old gel. If your local supplier really keeps 20+ sheets of each color in stock all the time, there is probably a high demand for color, and they probably sell it. Also, I have a huge color inventory at my theatre, much of it has been sitting around for years and years, and it doesn't seem to matter if color is new or old, if the color is going to burn through, it happens to the new and the old alike. In my experience anyway.

[derekleffew]

I second what Icewolf08 said. In your application, only Apollo Heat Shield (or maybe another brand) and Color Extenders would have helped your situation. Even then, using a color such as R59 in S4-PAR EA uplights running at 100% is dicey at best.

Counter-intuitively, I've found color media fades/burns faster in WFL/MFL than in NSP/VNSP. Who can explain that?

[JD]

Originally Posted by stantonsound

It was a conference at the convention center and the pars were used to uplight fabric columns. After about 2 hours, I got called from the interior decorator that had been hired to design the fabric, flowers, and decorative lighting. She said that the lights weren't purple anymore.

I noticed at Disney that they were using diachronic plates in most of the stationary indoor S4's. Guess they got tired of changing gels! Sounds interesting, but I am sure expensive to use in 6 inch frames, and many of their 64's (8 inch frame) were that way as well. I would suspect for the rest of us that they would be too fragile. Anybody else using them on here?

One funny effect, when you are off axis, the gel is of course a totally different color! Always a bit of a brain tease to see a light that looks to be gelled yellow throwing a deep violet beam! Kind of a neat effect...

[icewolf08]

I have used dichroics on occasion. Sometimes I designer needs the purity of color that you get from them, and sometimes they like them for the funky colors that you can get with them. I also use the 2" rounds in the MR-16 track lighting above my desk in the booth because I was tired of replacing gel. It is true though, people walk in the booth and wonder where the blue light is coming from since the off angle of the dichroic looks pink-ish.