Conventional Fixtures How big is a 6" cut of gel?

Dimensions of a 6" cut of gel ?

  • 6"x6", duh.

  • 6.25"x6.25"

  • 7.5"x7.5"

  • Other (please specify...)


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East Coast - Brooklyn to be specific, so USA.

We use actual cut size, so 6-1/4", 7-1/2", then 3-/1/8" x 4-1/2" for my ancient L&E MiniStrips.
 
And what part of the country/world are you from?
@steve b.
To begin with, it depends upon the fixture. Gels cut to fit Strand / Ianiro 6" Bambino 2KW fresnels are 8-sided and, from memory, approximately 8-1/4" across flats. Gel's cut to fit 6" Strand Ianiro Polaris IKW fresnels are also 8-sided but smaller than those for the 6" 2K's UNLESS the person ordering the Polaris 6" 1 K's were clever enough to order them with their accessory holders reversed making their color frames and barn doors the same size as their larger Bambino big brothers.
If you're speaking of luminaires more commonly available in North America, fixtures such as the Altman 360, 360Q and 65 + 65Q 6" Fresnels along with the Strand 2200 series (2204, 2209, 2112, 2212 & 2216) 7.125 to 7.25 " square is probably more the size you're looking for. Let's expound upon this a little further:
If you measure the full dimension of the frames and cut the gel a touch larger than the actual frames (Such as folks commonly do when capturing a sheet, or roll, of gel within a frame and cutting around the frame with their scissors) you'll often find the excess gel emanating past the extremeties of the frames hangs up on the fixture's accessory clips and becomes time-wastingly / annoyingly problematic. Even moreso when stacking multiple cuts within one frame, such as when adding diffusion and / or heat-shields.
If you try to be a cheap-skate, pardon me, frugal conservationist / economist by cutting your gels appreciably smaller than the frame size / only slightly larger than the size of the frame's aperature, you'll find your economy potentially leads to two problems: 1; The gel cut will slide around within the frame often permitting uncolored rays of white light to escape past the edges of your cuts and / or 2; Shrinkage will occur as the gel heats and ages / matures leading to the same issues as problem one.
P.S. For bonus points ALWAYS clearly label / number EVERY cut of gel including any / all off-cuts from rolls and / or sheets.
Agreed: It takes a few moments while you're cutting.
The time, debates, and lost hair it'll save you for the rest of your days will make you glad you did.
Bottom Line: The correct size is the size which works for you and your fixtures.
Edit: To answer your second query, I'm writing from Hamilton / Waterdown / Burlington, Ontario, Canada. That's the extreme western edge of Toronto in the minds of native Torontonians.
Toodleoo!
Ron Hebbard.
 
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@ron, 7-1/4" ?, really ?

It's a 7-1/2" holder with a 7-1/2" frame. How did you come up with 7-1/4" ?

Decades using and cutting at 7-1/2", never had issues.
 
The distance between the blade of the chop board and the yellow spike tape, duh.
 
Offhand I can't think of an instrument who's frame takes a true 6" square of gel. With that in mind, if I was at a lighting hang, and someone said "go get me another 6" cut of R02" I would assume they were talking about a 6x instrument or a 6" Century/Altman/L&E/Capitol Fresnel.
 
Offhand I can't think of an instrument who's frame takes a true 6" square of gel. With that in mind, if I was at a lighting hang, and someone said "go get me another 6" cut of R02" I would assume they were talking about a 6x instrument or a 6" Century/Altman/L&E/Capitol Fresnel.

Pretty sure we've had this discussion. My memory is the 6" moniker came from the unit having a lens 6" in diameter.
 
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Relevant to this discussion, courtesy of City Theatrical.
 
@ron, 7-1/4" ?, really ?

It's a 7-1/2" holder with a 7-1/2" frame. How did you come up with 7-1/4" ?

Decades using and cutting at 7-1/2", never had issues.
@steve b. I believe I explained my rational. We used to purchase RoscoLux in rolls and use a fine blade in a slow band-saw (If you ran the band saw too fast you would fuse the edges of the layers together) to cut them into smaller rolls sized for 6" and 8" Strand Fresnels (Pattern 223's) and ellipsoidals of the day as well as Iris and Orion cyc tops and foots. The remainder of the rolls would be filed for cutting any / all odd ball sizes such as beam projectors.
Toodleoo!
Ron Hebbard.
 
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A '6" cut of gel' is for a 6" lensed instrument, thus 7.5x7.5. Ohio, Chicago, Las Vegas.
 
We call for gel by either it's actual size (which is how each folder is labeled in the file cabinet) or by the particular light. So I might say go grab 8 7 1/2" cuts of L202, or go grab me 8 cuts of L202 for a leko. But usually by gel size since we do have some lekos that take a 10" or 14" cut.
 
@ron,
It's a 7-1/2" holder with a 7-1/2" frame. How did you come up with 7-1/4" ?
Kliegl?
I love how each series of Kliegl 6" had their own colorframe size that could not be used with any other 6" Kliegl series or any 6" fixture for that matter. Why did they ever go out of biz?
even to this day whenever I see a Kliegl C-clamp in my workspace it magically disappears and is never scene from again.
 
When I was the ME for a theatre we called for gel a handful of ways depending on how we were feeling. Since we typically were referring to cuts that fit a fixture type, a '6" cut' would refere to a cut that fit a fixture with a 6" lens, much the same as how a "S4 cut" fits a source 4. Of course, using Lightwright we standardized frame size labels within the organization, so a 6.25x6.25" cut was "A-size" and 7.5x7.5" was "B-size" and so on. Of course, like color coding cable lengths, this size code was particular to our theatre, but it worked very well for keeping everyone on the same page and keeping the gel file organized.
 
When I was the ME for a theatre we called for gel a handful of ways depending on how we were feeling. Since we typically were referring to cuts that fit a fixture type, a '6" cut' would refere to a cut that fit a fixture with a 6" lens, much the same as how a "S4 cut" fits a source 4. Of course, using Lightwright we standardized frame size labels within the organization, so a 6.25x6.25" cut was "A-size" and 7.5x7.5" was "B-size" and so on. Of course, like color coding cable lengths, this size code was particular to our theatre, but it worked very well for keeping everyone on the same page and keeping the gel file organized.
There's your key phrase: "within the organization". You had organization to begin with. Try not to be too shocked. "Organization" is something many places DON'T have.
Toodleoo!
(Organized blind old geezer)
Ron Hebbard.
 
What are these " of which you speak? Seriously though, where I work we spec and sort gel by the fixture type, and here in Oz fixtures aren't usually described by their lens size. I've never used measurements much anyway, since I've generally cut against either a template or the edge of a gel frame.
 
What are these " of which you speak? Seriously though, where I work we spec and sort gel by the fixture type, and here in Oz fixtures aren't usually described by their lens size. I've never used measurements much anyway, since I've generally cut against either a template or the edge of a gel frame.

If you use a zoom version of the S4 ellipsoidal as well as an S4 Par, do you keep the gels in separate folders, or whatever ?. Both use the same 7.5"/19 cm frame size as note.
 
There's a lot of legacy and anachronism in theatrical terms, which I generally support. In fact, I still like to call out RoscoluX gel with an x (x99, x05) to differentiate from Roscolene. Which is a totally useless practice and just confuses people, but I like the history. Calling a 7.5" x 7.5" gel a 6" cut (to fit an instrument with a 6" lens but 7.5" gel frame) made some sense before the development of the S4, with a 6.25" gel frame, that practically holds a 6" piece of gel. Heck, when I first started using S4s, we labeled the barrels as 6x9, 6x12, etc. to fit with the Altman system. Took a while to adopt the beam angle nomenclature. So I support hanging onto the old system, even if it does actually confuse matters. We're all just going to have to clarify the standards in every house.

On a pratical note, I cut gels for S4s at 6" square, because most gel sheets are 20x24, so I get 12 per instead of 9. And I know I'll get outrage, but when using Lee Filters which are 21x24, I cut gels for 7.5" frames at 7" for the same reason. The horror!

Now should we talk about 2x4s and 24' trucks?
 

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