Colortran Ellipsoidals & Gobos

Yes.
 
...And by turning orange, you mean red hot? I'm not sure if this is normal. I've never seen it happen with a S4, Shakespeare or SL but since your instrument probably has a metal reflector the beam is alot hotter. Maybe this is another question for Gam. Your gobo will not last as long if your lamp is not aligned correctly. Otherwise it should last awhile. I imagine it will be pretty warped after the run though.
 
I could be wrong, but I dont think it turned orange from being red hot but b/c of a chemical change caused by the heat to the paint/treatment on the metal. I have had this happen before too, but not to and entire gobo, just to a small area of a piece of equipement (dont remember what now.... maybe it was our followspot)
 
zackw250 said:
Has anyone used any Colortran 5/50 Ellipsoidals with steel gobos? If so, how was the projected image? Was it crisp when you wanted it to be? Did you have to purchase any special adapter for the gobo?
Yes I have in my local area theater which happens to own all colortran fixtures for the main theaters and Strand SLs for a smaller theater. Pattern wise they will be sharp focused when you want them sharp and gobos do not need any special adapters to appear or actually be in sharp focus on that type of fixture, trust this, one show that I went in to help with load in, 10 Gobos were used in colortran 5/50s and all projected patterns crisp and clearly
 
propmonkey said:
it has that but i want to be able to focus it. our other coves lights are strands and those you can move the lamp foward or back.
Colortrans Also have something similar to a Strand SL or ETC Source 4 lamp centering/ Peak-Flat knob... As for the Burning gobo... something is wrong in that fixture.. no Enchanced Ellipsoidal should turn any Gobo Bright orange
 
<As for the Burning gobo... something is wrong in that fixture.. no Enchanced Ellipsoidal should turn any Gobo Bright orange>

I totally agree. The lamp will throw a fair amount of heat through the gate, but enough to heat the steel gobo to a bright orange- wow! It sure sounds like the fixture is peaked out-
 
Making a gobo glow orange is nothing new, at least to me. I don't think I've encountered a single experience in my days as a lighting tech where the gobo DIDN'T glow orange. Then again, all of my fixtures are about 20 years old, so. Still, we've had all of our gobos for years, without problems. Only issue is warpage, and that hasn't been major enough for us really to pay attention.

Smoke is also nothing new; gobos will usually smoke a bit when you first put them in, or even when you reuse them.

Donuts help because of the way ellipsoidals focus light. They cut off on stray, unfocused beams and really sharpen the image. It's kind of weird at first glance that they actually work--shouldnt that donut be making the beam smaller?--but they do sharpen the image. Search the internet for them; they go into a fixture's gel frame, and it's essential a piece of sheet metal (or the likes) with a small circle (apeture) cut into it.

As for the gel frame. I'm not sure what type of gobo you got. From you saying that it was "orange," I'm guessing that you got it to work in your fixture, with whatever holder/system you had available to you.

As for the fixtures being good projectors, well, if you already have the gobo and it works, you'll just have to see for yourself I suppose! Always depends on what effect you're trying to generate; if the gobo is supposed to light up the actors, like a diffuse gobo for a forest, you will need a fairly to very strong fixture with it, so it will stand out over the normal wash; if you're just trying to project a pattern on a wall, you won't need as much light.

Just my dual lincolns
 
I own a number of these fixtures and I found that they perform well after performing two important modifications - applise for their use as a spot and a pattern projector. The first modification is that the lamp is actually too far into the reflector. If you remove the lamp holder you will see there are for aluminium plates between the lamp housing and the lamp holder. You can remove two of these and you will find the light intensity increases and is more even. The second modification is to remove the lens tube and check the diameter of the shutter gate opening. If it is three inches it is too big. You need to disassemble the shutter assembly and make one replacement palte from 22 guage steel sheet. The centre hole should be 2.5 inches in diameter. Reassemble the shutter assembly an re-install. You will now find the fixture should produce a sharp eged circle of light, smaller in diameter but noticeably brighter. When I did this originally I did side by side comparisosn between modified and unmodified fixtures. The modified fixture will project sharp gobo patterns with more punch. This works because the larger gate allows out of pahse light into the lens system which poduces light cancellation thereby reducing the light coming out of the fixture.
 
The first modification is that the lamp is actually too far into the reflector. If you remove the lamp holder you will see there are for aluminium plates between the lamp housing and the lamp holder. You can remove two of these and you will find the light intensity increases and is more even. The second modification is to remove the lens tube and check the diameter of the shutter gate opening. If it is three inches it is too big. You need to disassemble the shutter assembly and make one replacement palte from 22 guage steel sheet. The centre hole should be 2.5 inches in diameter. Reassemble the shutter assembly an re-install.

Interesting observations. I wouldn't have thought that any fixture has more than one plate under the lamp base. Is it possible that this was an after market modification? Not familiar with this fixture but if much like a 360Q and all three above mentioned plates were tapped, it no doubt was other than factory. You would never find three individual plates all three of them tapped in use. This much less if people over-tighten lamp base focus screws, and the center locking screw (if similar) often enough, they would tend to bend that aluminum plate inward if only a single plate. Three plates would tend to prevent this as a surmised reason that you might find three plates in a fixture.

Anyway, just curious in thinking possibly that there shouldn't be three plates at all behind the fixture - too thick a layer of aluminum that's not laminated... interesting in how it would react to the heat. I would think that the top layer would warp and if lamp base thru bolted, it would crack.

Yep three plates would tend to raise the lamp up by what 3/8" which might be too much to bench focus adjust for.

Interesting also the 22ga steel concept at the gate. Sounds very much like what adding a donut to the gel frame slot would do in cleaning up the image quality. Unless that hole in the gate were a really clean hole - uniform and without scratches, it's going to tend to burn up really fast such as a shutter, gobo or iris due to the heat. 22ga steel is a bit thin for my tastes - I wouldn't go with less than 16ga and if at it I would do 14ga. Still I would think the donut would clean up your image sufficiently without modifying what's engineered to be the proper size for the max. flood focus of the light.
 
The manual shows four plates. The 22 guage steel is the same guage that Colortran used to manufacture the original 5 plates used to sandwich the four shuters. They use four spring clips to hold this lot together. By the way the manual also says that the front lens is a 6x9 it is actually a 6x6.5, I found this out the hard way when I bought a 6x9 to replace cracked lens and found that the focus position moved forward to the front of the lens tube and I got a smallet diameter light pool, closer to a 15 degree fixture. The accuracy of the hole filing is not quite as critical as you would think. I use a hole saw, then file out to a scribed line and check the roundness with a polystyrene cup. The taper works great for checking roundness of holes. Doing this gives great results and makes these fixtures work. I have heard many complaints about them and straight out of the box they are not very good but they can work well. I should mention mine are the Lee Colortran Vintage.

The heat is not a problem as you are actually shortening the thermal path from the lamp base to the outside of the fixture. This reduces the thermal resistance which will allow the base to run cooler. The cooling comes from heat radiating from the outside of the fixture and convection from air moving over the outside. Adding surface area and mass inside the fixture won't help unless you have a fan inside and/or lots of cooling slots. These units have neither.

Hope this helps
 

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