Help(Theater Student)

ryancomet

New Member
I am a Lighting student, and i am writing a dissertation on incandescent sources versus led sources, and their impact on design. i have written a section about how leds stack up to incandescent sources technically, but if anyone has some nuggets of information about how leds have changed lighting design in a theatrical context it would be much appreciated.

Thanks!
 
It's changed the game significantly... surprisingly it's an incredibly broad subject, because you can look at it from many artistic angles. Most importantly additive vs (filtered) mixing, intensity shifts (red shift), ability to change the entire mood/theme of a look with only a few buttons... I think you should also explore time. LED has been competitive for a relatively short time, but has been in use for a relatively long time when discussing electric light sources. LED technology particularly in the entertainment industry has jumped by quantum leaps over the years, but I would still claim in my personal design aesthetic that an incandescent source still breathes and lives with a production with a sense of soul that I haven't found comparable in an LED source.... yet.
 
Incandescent light has a broad, full spectrum. By nature, LEDs are monochromatic sources that put out a narrow band of wavelengths. By using multiple LEDs with different wavelengths, a synthetic spectrum is created. This has also been aided by "white" LEDs although there is actually no such thing. A "white" LED is usually a deep blue LED with a pellet of phosphor in it that translates the blue to visible, useful light in the same way as a florescent tube does. The key takeaway is that LED sources do not have a color temperature like incandescent sources do. Color "temperature" in LEDs is a factor of the chosen phosphor and the mix between driving signals being put into the component LEDs. They have come a LONG way, but you can find their dirty little secret by shining them through a prism or diffraction grating.
 
I think what you are referring to is covered by the CRI of the fixture.
Most of the new offerings offer a CRI nearly identical to incandescent.

An LED fixture with low CRI or high colour temperature is going to make actors on stage look very odd compared to a warm white incandescent. It can definitely impact the mood of what you are trying to portray.

Some good examples of difference in CRI would be the Ovation line of fixtures from chauvet. The white-only E-260WW has a CRI of 96, whereas the RGBAL E-910FC only has a peak CRI of 83 when running in 3200K mode.
 
Last edited:
The CRI is the Color Rendering Index, or basically, how close to white is it really? Perfect would be 100%.
So, let's say there was a certain color of orange used on your props. Under incandescent, it would look orange. IF (hypothetically) the color wavelength of the paint or dye happened to be in part of the spectrum that the LED source was missing, the Orange object would appear gray. Now, in real life, pigments have a wide bandwidth of colors they reflect, so it would probably still look orange. But, it might not be the same shade of orange that you would see if it were lit by incandescent light. As mentioned above, most decent modern LED light sources are pretty high in CRI, so not that big a problem. HOWEVER, it is fun to look at them through the prism and compare. You would be surprised at the difference between them. Of course, take a look at a HPS or Florescent lamp and you will see why they look "off" !
 
how does the monochromatic light affect the appearance of the light on stage? this is not something i have considered and is an interesting concept but i dont understand how this affects the light.

Look up meteramism for some examples. The discontinuous spectrum of LED fixtures has different effects from the continuous spectrum of incandescent units. Sometimes this is bad. Sometimes it is good.
 
I remember the first LED cyc light in a demo at work.... probably like over 15 or more years ago. Minds' eye it had the intensity of a 300w lamped 6-cell cyc light in output, and was not sufficient for our 1Kw needs. In general back than and up until recently the CRI has been a huge problem. CRI is not the correct measurement for LED sources but is still the norm. The accurate CRI like standard I forget the name of is not much offered or used but would be good to research in the how its' different and more accurate concept.

Interesting concept for the prism above, fascinating.

In some cases these days I cannot match the light output of a LED source verses T-5 fluorescent or incandescent, but in most fixture design cases I base my fixture design off of luminous output of a filament lamp and RGB+ or color temperature desired and luminous output as often a new design trade off. "This is the luminous output similar to a 15 Watt lamp" in one case recently for something someone else thought a source best without running the math. I try to gauge with the people requesting a product a incandescent lamp concept of output because that's what everyone bases their minds' eye concept of output from. Given LED fixture use, I fear just as most now can't imagine what a FFN lamp will look like at 20' throw, and most won't know a 6x9 lens train at similar throw... the future is going to be interesting for the next generation of designers and tech people to figure out.

A definite advantage of going LED is the wasted heat from the filament having a huge factor on how you design what it's put into for that heat compensation. And again being able to dial in the color temperature or saving having to add a scroller to color the light. Also, the overall wattage of a system has gone way down. 20' square display booth I'm working on, will be probably given three 20 amp circuits, but can probably be one given it's mostly LED in use.

Hate LED's but becoming the mainstay's of what I fabricate for a living. Even fabricating a LED source for kitchen counter light given the T-2 fluorescent lamps I was using are no longer sold.
 
This article was recently posted on the ETC blog discussing color, and light's impact on how it's seen, it outlines 2 pretty neat experiments/tricks that can be done with light, and could be a good discussion point for your topic.
 
Design isn't all about how pretty it is either! An architect won't keep clients no matter how sexy his buildings are if they cant stand up on their own, and a design is no good if it cannot be implemented in an efficient and cost effective manner.
How LED has changed our world in the manner of how much weight is traveling in trucks, how many services you need for power, how much of a footprint you need for dimer beach... Where designers were once limited to a few colors of each system, suddenly the whole world has been opened up.

But that's not all! Its just like camping, ounces make pounds, and pounds make tons. 30 tons goes quick on a truck, and if you can save thousands of pounds of copper and fixtures and dimmers and everything else that comes with conventionals, that's alot of space and money that just got opened up for more cool automation stuff, or better fixtures, or cooler props, or better sets.

Non touring world? Less trouble shooting. Less components to fail and trouble shoot. Less lamping.

The impact on design will win the crowds hearts, but the impact on logistics will win the war.
 
but you still have to get it right in output and color temperature . That plus fixture options in what it does better than a more point source arc light especially going reflector based these days.

Searching for a new PAR38 120w halogen dock light, LED's are not powerful enough even with given.3 technology to match output. Filaments, or the inner capsule connnection breaks once the spot fixture is hit by a truss cart being pulled off the truck. Just don't make PAR 38 lamps like they used to. I have a stash of 150w non-halogen, incandescent 150w PAR 38 lamps I'll be putting into use but after that... I have two samples from premium brands coming in. LED is not quite there yet for PAR 38 dock light needs yet. Tried CFL, Metal Hallide, Cold Cathode and LED sources so far.


Every year LED's get cheaper and better, but in many cases the LED is not what is best.
 

Users who are viewing this thread

Back