roundels clear or spread?

[rschroeder]

Hey I am new to the forum and working at a high school. We are ordering roundels for our strip lights. The vendor asked me if I wanted spread or clear.

I am not sure which one I want, can anyone give me info on what the difference is? I am pretty sure they both are colored although the clear would seem to suggest differently.

They will be used in a black box theatre with about 110 seats in an arena configuration. Which one would work best?

Richard Schroeder Lincoln Northeast High

[icewolf08]

Think of roundels like the front of a PAR lamp. If you get them in clear it is like a VNSP PAR. You should be able to get roundels in different spreads, but maybe not. However, the spread lens is usually like an MFL PAR in that it is textured to spread the light out more. I have also seen roundels that are frosted like an NSP PAR. So if you are familiar with PAR fixtures, that might help things make more sense.

I assume that since you have a blackbox space, you have lower trim heights. So you probably want a spread lens for better coverage.

[rschroeder]

Actually the trim height is pretty decent around 18'. I don't think more spread is needed. I am wondering which variety lets through the most light, if there is any diffference.

[icewolf08]

Originally Posted by rschroeder

Actually the trim height is pretty decent around 18'. I don't think more spread is needed. I am wondering which variety lets through the most light, if there is any diffference.

Well, this is not a simple question. Each different color will let through different amounts of light, just like gel. They have a given transmission percentage. A clear lens will give you a more concentrated beam which means that it will be brighter in a smaller space. A spread lens may pass exactly the same number of photons but it spreads the light out thus you get more coverage at an apparent loss of lumens.

At an 18' trim, you probably want the spread lenses unless you need a really tight beam. You may want to ask your dealer if they have any in stock that you can test and then make a decision.

[rschroeder]

[QU

At an 18' trim, you probably want the spread lenses unless you need a really tight beam. You may want to ask your dealer if they have any in stock that you can test and then make a decision.[/QUOTE]

I have six 8" strips 4 circuit. the acting area is around 20' by 20'. I think the clear would probably be better since they are more concentrated and we have a large # of strips for the space.

I will ask the vendor if they can provide samples. Good idea.

[icewolf08]

The other option, if you find out the manufacturer of the roundels you may be able to look up the photometrics. They might be available on a manufacturer's website or spec sheet or in the Photometrics handbook. If you have the photometric data you can calculate the coverage that you would get from the different lens types.

[derekleffew]

I'm assuming these are to go into R40 strips, such as these?

http://mail.altmanltg.com/publicsyne...ID=&Country=US

The spread or stipple variety help to alleviate "scalloping" aka "color fringing" clearly shown in this picture:

http://www.controlbooth.com/forums/l...tml#post111001

As Icewolf said, rondels come in three flavors: clear (smooth on both sides), stipple (texture similar to R100 on the inside), and spread ([I believe it's usually 40°] heavy parallel lines meant to spread the light along one axis, an effect similar to R104).

If your striplights are in fact R40 strips, they probably take a two part metal "combination" frame. Putting the two pieces together one way leaves a 1/4" gap for the rondel. Reversing the inner piece allows for gel to be sandwiched between the two pieces. If yours are like this, I would not be buying rondels, which are expensive, heavy, breakable, and come in limited colors. I'd use plastic colr media (gel), in either R120,121,122 or R124,125,126; and still maintain the possibility to put in any of the approx. 800 colors available accross the four major manufacturers.

The clear or plain rondels will pass the most light The spread will pass the least. Actually the light loss through the glass is insignificant--the loss of intensity comes as to how the light is distributed. Before ordering an entire set, see if your vendor can supply you with one of each type with which to experiment. As you're looking at approx. $25/each for all types, this is a significant expenditure.

This page shows Altman 5 5/5" rondels and the combo color frame for R40 strips.

edit:

Originally Posted by rschroeder

...I have six 8" strips 4 circuit. ...

Okay, ignore what I said about R40 strips. Do you have PAR56, PAR64, or older style strips using 200W/300W A-lamps?
These?

http://www.controlbooth.com/forums/g...9-blinder.html

All the more reason to buy gel instead of glass if at all possible. Rondels in 8" variety are freakin' expensive! If the fixtures cannot take gel, you may want to look at a product from http://www.fxlight.com/ez-ht.html.

[rschroeder]

I am sorry I can't type They are actually 8' (foot) Altman 528's I know rondels are expensive, but they are so durable and just have a better look. The strips are also above risers and somewhat difficult to access, so it will be nice to not need to change the colors. Since we don't have a cyc there is no scalloping so I am thinking the clear are best.

Thanks for your help . Especially the photo, looks like a few strip light issues I have had in the past, using lux I might add.

[Les]

Is there a separate reflector for each lamp? If so, you probably have to use roundels since they don't accept gel frames. From what I remember, each reflector has a hinged ring which the roundel is clasped in to. I believe this to be true atleast with the 520's which use A lamps, but it's very possible that the 528's use PAR 38 or R40 lamps.

If your strips use 'A' lamps, you can get the clear roundels but use frosted lamps or vise versa.

[derekleffew]

Originally Posted by Les

...but it's very possible that the 528's use PAR 38 or R40 lamps. ...

The Altman 528-8 was intended to take PAR38 or R40 lamps. I don't know of anyone ever using the more expensive and uneven PAR38 lamps in them. Back in the day, the lamp choices were 150R40/SP, 150R40/FL, 300R40/SP, 300R40/FL. What lamps are you using in these today, rschroeder? This?


300BR/FL [21213] - $16.70 : Light Bulbs at Bulbman.