WEBVTT - TechStuff Steps Out of the Limelight 0:00:04.400 --> 0:00:07.760 Welcome to tex Stuff, a production from I Heart Radio. 0:00:12.160 --> 0:00:14.920 Hey there, and welcome to tech Stuff. I'm your host, 0:00:15.080 --> 0:00:18.440 Jonathan Strickland. I'm an executive producer with I Heart Radio 0:00:18.560 --> 0:00:21.919 and I love all things tech and this episode is 0:00:21.960 --> 0:00:26.840 a continuation of my previous episode about lighting for stage 0:00:26.880 --> 0:00:30.440 and screen. These shows are in response to a request 0:00:30.560 --> 0:00:34.880 to talk about Kleig lights, which I had just managed 0:00:35.000 --> 0:00:38.519 to mention towards the end of my previous episode with 0:00:38.600 --> 0:00:42.200 the introduction of the brothers Kleigel, who started a stage 0:00:42.240 --> 0:00:46.839 theater lighting company in eight nine six. So for this episode, 0:00:46.840 --> 0:00:50.200 we're going to stick with stage lighting and we'll bring 0:00:50.280 --> 0:00:53.320 that up to the modern era before we switch gears 0:00:53.360 --> 0:00:56.360 to talk about lights that engineers developed specifically for the 0:00:56.360 --> 0:01:00.400 purposes of film and television, because they largely built old 0:01:00.480 --> 0:01:04.160 upon the lighting technology that was made for the stage. 0:01:04.200 --> 0:01:08.200 As a reminder, lighting was always important and that you 0:01:08.440 --> 0:01:10.880 want your audience to be able to see what's going on. 0:01:11.080 --> 0:01:15.840 But for centuries, lighting was almost entirely about visibility and 0:01:15.920 --> 0:01:21.360 not artistic expression. That really began to change around the 0:01:21.440 --> 0:01:24.520 very end of the nineteenth century and into the early 0:01:24.600 --> 0:01:28.560 twentieth century. Part of that shift was due to advances 0:01:28.640 --> 0:01:32.000 in technology. It was only through the transition to gas 0:01:32.160 --> 0:01:36.600 lights and then electricity where directors really had the capability 0:01:36.680 --> 0:01:40.560 to make more precise, fine tuned adjustments, to create new 0:01:40.600 --> 0:01:44.080 effects and moods, and to really make lighting part of 0:01:44.120 --> 0:01:48.320 a scene. By the early twentieth century, many theaters around 0:01:48.360 --> 0:01:52.360 the world were embracing electric lights figuratively. If you did 0:01:52.400 --> 0:01:56.120 it literally, you would get burned and or electrocuted. Typically, 0:01:56.440 --> 0:02:00.520 these theaters were installing incandescent bulbs in the foot lights 0:02:00.560 --> 0:02:02.640 and in the border lights and the strip lights. These 0:02:02.680 --> 0:02:06.280 are lights that are all around the stage that project 0:02:06.440 --> 0:02:09.359 light onto the stage itself, and that was just for 0:02:09.520 --> 0:02:12.480 the general stage lighting. Some would still use the older 0:02:12.480 --> 0:02:17.840 electric arc lights, the carbon arc lights for floodlights and spotlights, 0:02:18.160 --> 0:02:22.359 while other theaters would switch to extremely bright and very 0:02:22.440 --> 0:02:26.160 hot incandescent bulb lights, and these would be in the 0:02:26.280 --> 0:02:30.400 one thousand what range or more. Theaters began to phase 0:02:30.440 --> 0:02:34.400 out carbon arc lights and then the even older lime lights. 0:02:34.440 --> 0:02:38.200 Those were lights that used and oxygen hydrogen gas to 0:02:39.200 --> 0:02:42.640 heat up a piece of lime so that it would glow. 0:02:43.520 --> 0:02:47.279 They would get rid of those in favor of incandescent spotlights. 0:02:47.680 --> 0:02:49.639 And it's hard for us to get a full appreciation 0:02:49.680 --> 0:02:53.359 of how these changes allowed for new artistic expression, because 0:02:54.160 --> 0:02:56.880 now we live in an era where that is commonplace, 0:02:57.520 --> 0:02:59.600 and it's hard for us to remember that this had 0:02:59.600 --> 0:03:03.040 a pro found effect on audiences at the time, because again, 0:03:03.080 --> 0:03:06.640 we're used to it. But one example of how transformative 0:03:06.880 --> 0:03:10.800 these techniques would be involves an actor and theater manager 0:03:10.960 --> 0:03:15.520 named David Belasco. Like Sir Henry Irving, who I spoke 0:03:15.560 --> 0:03:18.040 about in our last episode, he was known for producing 0:03:18.080 --> 0:03:21.560 plays that didn't always meet with critical approval from a 0:03:21.720 --> 0:03:27.400 textual standpoint, but they were technically magnificent. Blasco was similarly 0:03:27.520 --> 0:03:31.000 known for his theatricality, if not for his contributions to 0:03:31.080 --> 0:03:36.760 high drama. Unlike Irving, however, Belasco didn't issue electric lights. 0:03:36.800 --> 0:03:41.320 Irving only wanted gas lights. Belasco went with electric lights. 0:03:41.800 --> 0:03:45.200 Belasco would end up producing a staging of the play 0:03:45.360 --> 0:03:49.280 Madam Butterfly, and in this production, he used a white 0:03:49.360 --> 0:03:52.600 backdrop at the back of the stage and he could 0:03:52.680 --> 0:03:56.880 light that in different ways to simulate various effects. In 0:03:57.000 --> 0:04:02.080 Madam Butterfly that included a fourteen minute sequence that featured 0:04:02.120 --> 0:04:05.160 a simulation of the passing of time by lighting the 0:04:05.160 --> 0:04:09.160 backdrop to mimic a sunset the night and then the 0:04:09.200 --> 0:04:12.360 subsequent sun rise. And one of the people who saw 0:04:12.400 --> 0:04:16.760 this production was the great Giacomo Antonio Domenica Michelle Secondo 0:04:16.880 --> 0:04:21.440 Maria Puccini, or Puccini for short. He's an Italian composer 0:04:21.560 --> 0:04:26.279 famous for his operas. Puccini didn't understand very much English, 0:04:26.360 --> 0:04:29.720 but he was so impressed by the artistic display he 0:04:29.800 --> 0:04:32.760 saw in that theater that he decided to adapt the 0:04:32.800 --> 0:04:37.440 story into an opera Madama Butterfly. And presumably without the 0:04:37.440 --> 0:04:41.960 theatricality to help convey the emotion and intent of those scenes, 0:04:42.600 --> 0:04:45.920 that never would have happened, we would not have that opera. 0:04:46.360 --> 0:04:51.000 Blasco's fame largely centered on his sense of the theatric 0:04:51.040 --> 0:04:55.120 and he was known for incorporating many complicated technical processes 0:04:55.440 --> 0:04:58.880 to create effects in the theater. His name on a 0:04:58.920 --> 0:05:02.760 production was enough to sell tickets, even as drama critics 0:05:02.800 --> 0:05:07.320 sometimes lamented that the material he chose wasn't necessarily elevated. 0:05:07.760 --> 0:05:11.520 But there's no doubt that his work really pushed lighting 0:05:11.560 --> 0:05:16.120 into a new level as far as theatrical presentations are concerned. 0:05:16.760 --> 0:05:19.320 One thing I mentioned in the previous episode was the 0:05:19.400 --> 0:05:23.159 use of gels or color filters to create different effects. 0:05:23.600 --> 0:05:27.800 These are transparent sheets of a colored material and they 0:05:27.839 --> 0:05:30.520 fit in front of a lens of a light source. 0:05:31.080 --> 0:05:33.880 So light comes out hits this filter and then you 0:05:33.920 --> 0:05:37.200 get uh color of light coming out of the end 0:05:37.240 --> 0:05:39.840 of your of your light source. And the colors can 0:05:39.880 --> 0:05:42.799 simulate different types of natural light or they can create 0:05:42.839 --> 0:05:45.400 other effects. And we had come a long way from 0:05:45.480 --> 0:05:49.360 using bottles filled with different colors of liquid in front 0:05:49.640 --> 0:05:53.600 of candles that had transitioned to pains of stained glass 0:05:53.720 --> 0:05:58.400 and then later lacquer gelatine. But what is gelatine. Well, 0:05:58.440 --> 0:06:02.120 gelatine is a tasteless protein produced from collagen, which is 0:06:02.120 --> 0:06:05.159 a connective tissue found in animals, like in our skin, 0:06:06.080 --> 0:06:08.640 the ligaments, all that kind of stuff. There's lots of 0:06:08.640 --> 0:06:11.920 collagen there. So this is a structural protein that helps 0:06:12.040 --> 0:06:16.960 hold stuff like well, us together. In Star Wars, they 0:06:16.960 --> 0:06:19.560 talk about how the force binds us. But when we're 0:06:19.560 --> 0:06:22.440 talking about animal bodies, we really shouldn't talk about the forest. 0:06:22.480 --> 0:06:25.600 We should talk about collagen, and that collagen is the 0:06:25.640 --> 0:06:28.719 base material for gelatin, which we use in all sorts 0:06:28.760 --> 0:06:33.320 of stuff, including and primarily in food products. If you've 0:06:33.400 --> 0:06:37.080 enjoyed a bowl of jello or a gummy bear, chances 0:06:37.120 --> 0:06:41.200 are you were scarfing down gelatin. Frequently, producers will take 0:06:41.279 --> 0:06:46.240 the byproducts from other processes, like from a slaughter house. 0:06:46.480 --> 0:06:49.159 So in a way, you can think of gelatine as 0:06:49.200 --> 0:06:51.720 a method for us to make sure we use more 0:06:51.880 --> 0:06:55.080 of the animals were slaughtering for stuff like you know, 0:06:55.240 --> 0:06:58.480 meat production or leather or whatnot, So you can think 0:06:58.480 --> 0:07:01.960 of it as avoiding waste. To produce gelatine, you gotta 0:07:02.040 --> 0:07:05.960 take animal parts like the bones and skins of stuff 0:07:05.960 --> 0:07:08.440 like pigs and cows. Those tend to be the animals 0:07:08.480 --> 0:07:11.240 that we use to make gelatine. And then you've got 0:07:11.240 --> 0:07:14.080 to boil this stuff for a really long time, typically 0:07:14.080 --> 0:07:17.640 in the presence of a weak acid, and as it boils, 0:07:17.680 --> 0:07:21.760 the collagen breaks down into gelatine. There's a lot of 0:07:21.800 --> 0:07:25.560 filtration and purification that has to follow before you can 0:07:25.600 --> 0:07:28.880 get to the industrial gelatine that we produced today, but 0:07:28.960 --> 0:07:33.200 generally speaking, that's the process anyway. One of the other 0:07:33.240 --> 0:07:36.480 things people use gelatine for was to make this transparent 0:07:36.520 --> 0:07:39.840 film that could be dyed different colors. The film would 0:07:39.840 --> 0:07:42.760 be used as the color filter for theatrical lights, and 0:07:42.800 --> 0:07:45.320 because they were made from gelatine, the industry began to 0:07:45.400 --> 0:07:48.960 refer to them as gels, and you can find gels 0:07:49.000 --> 0:07:52.960 and theater and TV film productions just regular video productions. 0:07:52.960 --> 0:07:56.280 But these days they are not made out of gelatine, 0:07:56.640 --> 0:08:00.360 and there's some good reasons for that. Gelatine, while cheap 0:08:00.440 --> 0:08:05.160 and relatively easy to produce, isn't the most resilient material. 0:08:05.640 --> 0:08:08.920 It could dissolve if it got wet, and it didn't 0:08:08.920 --> 0:08:11.680 stand up to the intense heat generated by lights for 0:08:11.840 --> 0:08:14.600 very long, so you would have to replace those gels 0:08:14.640 --> 0:08:18.360 fairly frequently. Now it doesn't really melt, but it does 0:08:18.760 --> 0:08:22.280 char and it also gets super brittle as it gets heated, 0:08:22.600 --> 0:08:25.040 so you would only get a little use out of 0:08:25.040 --> 0:08:28.160 one before it would break and require a replacement. Still, 0:08:28.480 --> 0:08:32.120 the development of gels gave directors and lighting designers more options, 0:08:32.400 --> 0:08:34.480 and they would be used in the industry up through 0:08:34.559 --> 0:08:39.240 the mid nineteen seventies, even after engineers developed other solutions. 0:08:39.880 --> 0:08:44.120 Another lighting accessory that emerged was the gobo. A gobo 0:08:44.280 --> 0:08:47.160 is a screen that has designs cut into it to 0:08:47.280 --> 0:08:50.560 create a special lighting effect. For example, you might have 0:08:50.600 --> 0:08:53.760 a screen that has the shape of leaves cut into 0:08:53.800 --> 0:08:56.040 that screen, and when you place that in front of 0:08:56.040 --> 0:08:59.160 a light, the screen allows light to pass through the 0:08:59.160 --> 0:09:03.280 cutout shape and that gets projected onto the stage. That 0:09:03.480 --> 0:09:07.839 is where Gobo Fraggle's name comes from, the Gobo. By 0:09:07.880 --> 0:09:10.800 the nineteen twenties, we started seeing some of the earliest 0:09:10.880 --> 0:09:15.160 textbooks dedicated to lighting, such as Theodore Fuchs. Stage lighting 0:09:15.760 --> 0:09:19.080 seems pretty straightforward. It was around this time that some 0:09:19.200 --> 0:09:22.520 theaters began to incorporate a special kind of lens in 0:09:22.600 --> 0:09:26.240 theater lights to provide a more focused beam. The lens 0:09:26.320 --> 0:09:30.720 is called the Frenelle lens. That's spelled f r E 0:09:31.160 --> 0:09:35.480 s in e L. But it's named after Augustine Jean Frenell. 0:09:36.160 --> 0:09:40.160 Now he didn't actually invent this particular lens. That honor 0:09:40.240 --> 0:09:44.560 goes to George Louis le Clerc de Boeufon, who proposed 0:09:44.679 --> 0:09:47.800 this in seventeen forty eight. But what the heck is 0:09:47.920 --> 0:09:51.360 a Frenel lens? Well, first, we need to remember that 0:09:51.400 --> 0:09:55.400 the purpose of any lens is to redirect light. By 0:09:55.440 --> 0:09:58.800 creating a lens with a specific curvature, you can bend 0:09:59.000 --> 0:10:01.880 light coming from one side of the lens so that 0:10:02.040 --> 0:10:04.320 it exits the other side of the lens in a 0:10:04.360 --> 0:10:10.319 specific way. Eyeglasses do this. Eyeglasses bend incoming light, so 0:10:10.400 --> 0:10:12.920 that ends up hitting the retina in the back of 0:10:12.960 --> 0:10:17.160 the eye correctly to correct for some you know issue 0:10:17.559 --> 0:10:20.800 with the shape of the cornea, and the cornea is 0:10:20.840 --> 0:10:23.920 either directing light too far forward or too far behind 0:10:24.000 --> 0:10:27.559 the retina, which messes with our focus and it creates 0:10:27.600 --> 0:10:31.840 either far sidedness or near sightedness. Now, good old Georgie 0:10:31.840 --> 0:10:34.840 Boy proposed that you can make a lens by cutting 0:10:34.880 --> 0:10:38.760 concentric rings of grooves on one side of a pane 0:10:38.760 --> 0:10:42.600 of glass, and that would end up using less glass 0:10:42.640 --> 0:10:45.680 than a conventional lens. Lenses tend to be you know, 0:10:46.920 --> 0:10:50.040 bulb bus They're actually named after lentils, So if you 0:10:50.040 --> 0:10:52.160 think of the shape of a lentil, that's why we 0:10:52.240 --> 0:10:54.920 call lenses lens. They were thought they look kind of 0:10:54.960 --> 0:10:59.120 like lentils. But that means that lens is particularly big 0:10:59.160 --> 0:11:03.120 ones for big, big lights get really heavy because you've 0:11:03.160 --> 0:11:06.680 got that thick glass to deal with. Well, George, he thought, 0:11:07.000 --> 0:11:08.640 what if we take a pane of glass and we 0:11:08.720 --> 0:11:11.760 cut grooves in it to redirect light, and we'll just 0:11:11.800 --> 0:11:13.840 make sure that each groove is positioned in such a 0:11:13.880 --> 0:11:18.000 way that as light hits the back of that lens, 0:11:18.040 --> 0:11:21.600 it gets redirected towards the center. And this was a 0:11:21.720 --> 0:11:27.199 really clever idea. Of the concentric circles act as refracting surfaces. 0:11:27.240 --> 0:11:29.960 They all bend those parallel light rays into a common 0:11:30.000 --> 0:11:33.480 focal length, and otherwise that would require a much thicker 0:11:33.480 --> 0:11:36.959 traditional lens. Each ring of this lens focuses the light 0:11:37.040 --> 0:11:39.920 hitting that section towards the center, and for Nell's contribution 0:11:40.120 --> 0:11:44.120 was to actually take this type of lens and install 0:11:44.240 --> 0:11:48.600 them in lighthouses to produce that powerful focused beam rather 0:11:48.679 --> 0:11:51.320 than a more diffuse one. So if you ever think 0:11:51.360 --> 0:11:54.320 about what it looks like when you see the the 0:11:54.360 --> 0:11:56.920 beam of light emerging from a lighthouse, that's because the 0:11:57.000 --> 0:12:00.760 light is passing through Fennell lenses. The you of Frenelle 0:12:00.840 --> 0:12:04.800 lenses in theaters was so new in the mid nineteen 0:12:04.840 --> 0:12:08.120 twenties that that stage lighting textbook that I mentioned it 0:12:08.240 --> 0:12:11.760 from nineteen twenty six, it didn't even have an inclusion 0:12:12.040 --> 0:12:14.880 of Frenelle lenses in it, although they were starting to 0:12:14.920 --> 0:12:17.720 get used around that time, and while a few theaters 0:12:17.760 --> 0:12:21.040 were making use of the Frenelle lens. The popularity of 0:12:21.080 --> 0:12:24.040 it would really take off in the nineteen thirties. It 0:12:24.200 --> 0:12:28.040 significantly reduced the weight of the lights that were being used, 0:12:28.040 --> 0:12:30.439 and it also created a more concentrated beam that could 0:12:30.440 --> 0:12:33.400 be directed towards the precise location. So this was a 0:12:33.440 --> 0:12:36.960 big advancement in lighting now. In the early nineteen thirties, 0:12:37.240 --> 0:12:41.360 a lighting designer named Stanley McCandless published a textbook on 0:12:41.440 --> 0:12:44.840 stage lighting, and this would be the beginning of many 0:12:45.080 --> 0:12:49.080 of his contributions to the greater knowledge and expertise on 0:12:49.280 --> 0:12:53.040 lighting techniques for the stage, and many referred to McCandless 0:12:53.080 --> 0:12:56.480 as the father of modern stage lighting, though at least 0:12:56.559 --> 0:12:59.240 some of the sources I have encountered also suggests that 0:12:59.840 --> 0:13:03.240 the those techniques really belonged to another era of theater, 0:13:03.640 --> 0:13:06.520 that in the modern era we're starting to see a 0:13:06.640 --> 0:13:11.320 move away from those techniques, and that it's probably a 0:13:11.440 --> 0:13:15.000 good thing. We always want to see art evolve. McCandless 0:13:15.160 --> 0:13:22.439 argued that stage lighting really serves four purposes visibility, form, naturalism, 0:13:22.440 --> 0:13:26.280 and mood. That is, any decision made by a lighting 0:13:26.320 --> 0:13:29.280 designer should be done with the goal of fulfilling at 0:13:29.360 --> 0:13:32.720 least one of those four functions. If the light serves 0:13:32.760 --> 0:13:35.959 no purpose belonging to one of those four categories, then 0:13:36.120 --> 0:13:39.640 it's a distraction it shouldn't be used. On top of that, 0:13:39.840 --> 0:13:42.960 McCandless was working on designs that relied on the technology 0:13:42.960 --> 0:13:46.440 of the time, which mostly were all about lights that 0:13:46.440 --> 0:13:51.000 were mounted on rigs that had to remain stationary. Now, 0:13:51.040 --> 0:13:54.840 these lights typically hang from rigs that are above the stage, 0:13:55.000 --> 0:13:57.600 often in front of the stage, and they might be 0:13:57.679 --> 0:13:59.640 masked from view of the audience or they might be 0:13:59.679 --> 0:14:02.679 in full view. The lights typically hang from a scaffold 0:14:02.720 --> 0:14:06.200 like structure called a box boom, not a boom box 0:14:06.720 --> 0:14:09.840 that's a different thing, and they're mounted in housings that 0:14:09.880 --> 0:14:13.800 have points of articulation. So during the rehearsal process, the 0:14:13.880 --> 0:14:17.640 lighting designer's crew will carefully hang and aim each light 0:14:18.160 --> 0:14:21.680 toward the stage per the designer's direction. And because a 0:14:21.720 --> 0:14:26.040 production might need to represent many different lighting moods, perhaps 0:14:26.040 --> 0:14:29.520 to simulate different environments and different times of day, the 0:14:29.520 --> 0:14:32.040 crew might have to hang lights close to each other 0:14:32.280 --> 0:14:35.080 and then repeat the process of aiming each one at 0:14:35.080 --> 0:14:38.800 this particular point on the stage many many times, and 0:14:38.840 --> 0:14:41.720 once the lights are all in position, they pretty much 0:14:41.720 --> 0:14:44.360 stay that way. For decades, there was really no way 0:14:44.400 --> 0:14:47.480 to redirect light in the middle of a show, with 0:14:47.560 --> 0:14:51.040 the exception of perhaps follow lights or spotlights, and those 0:14:51.080 --> 0:14:54.760 would require a human being to operate those manually. Instead, 0:14:54.800 --> 0:14:57.720 the tech crew would control which lights were on during 0:14:57.760 --> 0:15:01.440 any given scene using the switchboard, so lighting could change 0:15:01.480 --> 0:15:04.040 from one moment to the next, but the lights themselves 0:15:04.080 --> 0:15:07.080 would remain stuck in whatever position the crew had put 0:15:07.120 --> 0:15:10.160 them in. You wouldn't have lights move from one part 0:15:10.160 --> 0:15:12.040 of the stage to another, they would just be in 0:15:12.120 --> 0:15:16.040 that one static angle. By the way, a little side note, 0:15:16.320 --> 0:15:18.760 I used to do this for my high school. I 0:15:18.800 --> 0:15:21.720 was in a couple of shows back in high school 0:15:21.720 --> 0:15:24.360 shortly after the invention of theater, and I was also 0:15:24.440 --> 0:15:27.160 a scrawny little kid back in those days. And our 0:15:27.200 --> 0:15:31.800 main light rig our box boom was tucked away in 0:15:31.880 --> 0:15:34.640 a little kind of hidden chamber up above the first 0:15:34.640 --> 0:15:37.640 few rows the audience, and it was just big enough 0:15:37.680 --> 0:15:40.280 for a tiny little person like I was to crawl 0:15:40.360 --> 0:15:43.240 back there and position the lights. And when I was 0:15:43.280 --> 0:15:45.960 doing it, the work was really hot, it was stuffy, 0:15:46.040 --> 0:15:49.360 it was dusty, and it was hard. Plus I was 0:15:49.640 --> 0:15:53.000 perched on a tiny little ledge above a twenty ft 0:15:53.080 --> 0:15:55.680 drop or so down to the floor with no real 0:15:55.720 --> 0:16:00.520 way to secure myself. Good times. Mccannle would go on 0:16:00.560 --> 0:16:04.240 to publish many more textbooks on stage lighting, becoming the 0:16:04.280 --> 0:16:07.760 foremost authority in the field for many years. The basic 0:16:07.840 --> 0:16:10.960 principle of the McCandless method is to light each area 0:16:11.040 --> 0:16:13.600 of a stage where actors are going to perform with 0:16:13.680 --> 0:16:16.800 two lights from above and each at an angle of 0:16:16.920 --> 0:16:20.160 forty five degrees to the stage and on either side 0:16:20.200 --> 0:16:23.280 of the center of the performance area. This creates an 0:16:23.280 --> 0:16:27.040 effect that makes more shadows and enhances the sense of 0:16:27.080 --> 0:16:30.560 separation of the actors from the background, makes it more 0:16:30.600 --> 0:16:34.800 three dimensional, and that is better than just lighting actors 0:16:34.800 --> 0:16:38.600 from the front that tends to create a more flattening effect. Now, 0:16:38.640 --> 0:16:41.960 I promise we're nearly getting done with stage lighting. When 0:16:41.960 --> 0:16:43.920 we come back, i'll talk about a few more advances 0:16:43.960 --> 0:16:47.400 that would follow, and then we'll transition towards film and television. 0:16:47.440 --> 0:16:58.480 But first, let's take a quick break. Around ninety three, 0:16:58.920 --> 0:17:03.280 stage theaters begin and to use ellipsoidal lights. And this 0:17:03.360 --> 0:17:05.080 is the type of light that I had to work 0:17:05.119 --> 0:17:07.080 with when I was in high school. So what the 0:17:07.080 --> 0:17:10.199 heck is an ellipsoidal light. Well, an ellipsoid is a 0:17:10.240 --> 0:17:12.359 type of shape, and it's what you get if you 0:17:12.400 --> 0:17:15.639 have a sphere and then you deform that sphere. So 0:17:15.840 --> 0:17:19.119 imagine you've got an inflatable beach ball and you press 0:17:19.280 --> 0:17:22.080 down on it, the ball deforms, and now you've got 0:17:22.080 --> 0:17:26.040 yourself a type of ellipsoid. So an ellipsoid light has 0:17:26.080 --> 0:17:30.199 a bulb that sits in a reflector, and that reflector 0:17:30.400 --> 0:17:33.840 is ellipsoidal in shape. The reflector typically is made up 0:17:33.840 --> 0:17:37.680 of little panels of reflective material, though it can be smooth, 0:17:38.359 --> 0:17:40.640 and the whole purpose of this is to direct light 0:17:40.840 --> 0:17:45.720 out through the lens in a very focused, concentrated beam. 0:17:46.119 --> 0:17:48.480 And this is really effective when it comes to directing 0:17:48.480 --> 0:17:51.760 as much light that that bulb can put out as 0:17:51.800 --> 0:17:55.320 possible toward the stage. Around this time, the bulbs that 0:17:55.359 --> 0:17:58.800 were in use were largely in the one thousand, fifteen 0:17:58.960 --> 0:18:03.160 hundred and two thousand what range. And again those incandescent 0:18:03.160 --> 0:18:05.359 bulbs that we used to light our houses, those typically 0:18:05.400 --> 0:18:08.920 were in thirty forty five or sixty watts, So this 0:18:09.040 --> 0:18:13.400 is way way way brighter. Now. The Kleigel Brothers produced 0:18:13.400 --> 0:18:17.720 an ellipsoidal Cleague light that stage theaters used, and the 0:18:17.800 --> 0:18:21.520 Polo Grounds in New York purchased Cleague lights in nineteen 0:18:21.640 --> 0:18:25.040 thirty three for a production of Romance of the People, 0:18:25.640 --> 0:18:28.640 and that is one of the earliest, if not the 0:18:28.680 --> 0:18:32.080 earliest use of Cleague lights in the theater. Around the 0:18:32.160 --> 0:18:35.959 nineteen forties, another advance would change lighting a bit, and 0:18:36.000 --> 0:18:38.920 this was the development of color filters made not out 0:18:38.960 --> 0:18:44.439 of gelatin but acetate. Acetate is a synthetic polymer, and 0:18:44.480 --> 0:18:48.280 the polymer is a long chain molecule. Acetate falls into 0:18:48.359 --> 0:18:52.320 the category of thermoplastics and it's used in lots of stuff, 0:18:52.400 --> 0:18:55.600 including glue, but it can also be used to make 0:18:55.680 --> 0:18:58.879 thin sheets of transparent material that can then be dyed 0:18:59.240 --> 0:19:02.160 and like jella, and it's super cheap to produce, so 0:19:02.240 --> 0:19:06.000 it became a standard in stage lighting around or so. 0:19:06.680 --> 0:19:09.040 But next on our list is an invention that would 0:19:09.080 --> 0:19:13.960 necessitate yet another shift in color filters, and that next 0:19:13.960 --> 0:19:17.640 big thing is the halogen light, which really started getting 0:19:17.680 --> 0:19:20.000 its use in the theater and film industries in the 0:19:20.119 --> 0:19:23.359 late nineteen sixties. Now, if you're a bit rusty on 0:19:23.400 --> 0:19:27.520 your chemistry, the halogens are a group of chemically related 0:19:27.680 --> 0:19:31.320 elements There groups seventeen on the periodic table, and they 0:19:31.320 --> 0:19:35.159 include fluorine and chlorine and bromine and iodine and a 0:19:35.200 --> 0:19:38.080 couple of others. And the word halogen comes from too 0:19:38.280 --> 0:19:43.000 Greek roots, how which means salt and gen which means 0:19:43.080 --> 0:19:46.840 to generate or to produce. And yes, all these elements 0:19:46.880 --> 0:19:52.080 produce sodium salts. There's sodium chloride for example, that's table salt. 0:19:52.560 --> 0:19:55.560 They also have another property that makes them really useful 0:19:55.680 --> 0:20:00.080 at high temperatures. They can combine with tungsten vapor, and 0:20:00.119 --> 0:20:03.040 tungsten is the substance of choice to serve as the 0:20:03.119 --> 0:20:07.639 filament in incandescent bulbs. Now, the idea of using a 0:20:07.720 --> 0:20:11.760 halogen gas in this case it would be chlorine back 0:20:11.760 --> 0:20:13.480 in lamps that that dated all the way back to 0:20:13.480 --> 0:20:16.560 the eighteen eighties. Chlorine gas very dangerous stuff, by the way, 0:20:16.560 --> 0:20:19.760 But it wasn't until General Electric patented technology in the 0:20:19.840 --> 0:20:23.520 nineteen fifties, this time with iodine as the gas, that 0:20:23.600 --> 0:20:26.480 we started seeing these kind of lights go into production. 0:20:26.880 --> 0:20:30.560 Halogen bulbs are a bit different from incandescent bulbs in 0:20:30.600 --> 0:20:33.840 a few important ways. First, as we've covered, they contain 0:20:33.920 --> 0:20:37.960 a halogen gas rather than the inert gases in incandescent bulbs, 0:20:38.560 --> 0:20:42.600 they are also much smaller and the bulb part the 0:20:42.640 --> 0:20:45.720 what would normally be glass with an incandescent bulb is 0:20:45.720 --> 0:20:48.800 actually a little envelope that's made out of quartz, and 0:20:48.840 --> 0:20:50.720 it has to be made out of something other than 0:20:50.760 --> 0:20:55.880 glass because halogen lights give off enough heat to melt glass. 0:20:55.920 --> 0:20:59.920 Just as with an incandescent bulb, the tungsten filament inside 0:21:00.040 --> 0:21:04.119 to halogen lamp heats up through resistance and then incandescence, 0:21:04.440 --> 0:21:07.600 and it also begins to vaporize. Bits of tungsten actually 0:21:08.359 --> 0:21:12.840 evaporate off of that filament. But with halogen lights, the 0:21:12.920 --> 0:21:16.320 tungsten vapor combines with the halogen gas and at a 0:21:16.359 --> 0:21:19.840 high enough temperature and interesting reaction begins to occur. The 0:21:19.880 --> 0:21:24.400 gas will start to redeposit the vaporized tungsten onto the filament. 0:21:24.920 --> 0:21:27.760 Now with light bulbs incandescent light bulbs, you can actually 0:21:27.800 --> 0:21:31.159 see the deposits of the tungsten on the inside of 0:21:31.200 --> 0:21:33.560 the glass bulb. That's why they get dark after a 0:21:33.680 --> 0:21:36.480 light bulb burns out, like they had a little dark spot. Well, 0:21:36.480 --> 0:21:39.359 with halogen lights you actually get a recycling process. The 0:21:39.440 --> 0:21:43.280 vaporized tungsten is returned to the filament that actually extends 0:21:43.280 --> 0:21:47.040 the useful life of the bulb. Halogen lights will last 0:21:47.119 --> 0:21:52.040 much longer than incandescent lights of a you know, equivalent brightness, 0:21:52.400 --> 0:21:54.960 and you can run the lights at a higher wattage 0:21:55.000 --> 0:21:57.640 with halogen bulbs, So that also means you can produce 0:21:57.720 --> 0:22:00.359 more light as a result, and that is perfect certain 0:22:00.400 --> 0:22:04.359 applications like a car's headlights, or stage lights, or film 0:22:04.400 --> 0:22:08.640 and television production lights. But there was one problem. Halogen 0:22:08.720 --> 0:22:12.359 lights get so hot that you couldn't use acetate color 0:22:12.440 --> 0:22:15.600 filters on halogen lights because the acetate would just melt. 0:22:16.160 --> 0:22:20.440 So the industry shifted to more durable polymer based products, 0:22:20.480 --> 0:22:25.960 like a polyester based material or milar polycarbonate. Neither the 0:22:26.000 --> 0:22:30.200 acetate sheets nor these newer materials were related to gelatin, 0:22:30.400 --> 0:22:32.960 the original stuff that everyone used. But everyone kept on 0:22:33.080 --> 0:22:36.399 using the term gel to describe these color filters, so 0:22:36.440 --> 0:22:39.000 even though it was no longer even remotely gelatin, the 0:22:39.080 --> 0:22:42.439 name gel stuck. Another big innovation that plays an important 0:22:42.520 --> 0:22:44.880 role not just on stage and screen, but in our 0:22:44.920 --> 0:22:48.680 everyday lives is the dimmer switch. Now, for a long time, 0:22:48.960 --> 0:22:51.080 you pretty much had two choices when it came to 0:22:51.119 --> 0:22:54.040 your lights, they were either off or they were on, 0:22:54.480 --> 0:22:56.880 and when they were on, they were as bright as 0:22:56.880 --> 0:23:00.040 they could be until they burnt out and that was it. 0:23:00.119 --> 0:23:02.480 But the dimmer switch allows you to control the intensity 0:23:02.520 --> 0:23:05.680 of light, moving from gradations between wow, it sure is 0:23:05.760 --> 0:23:09.120 dark in here to uh, holy cats, that's a bright light. 0:23:09.160 --> 0:23:12.000 But how does a dimmer switch work Well, the earliest 0:23:12.160 --> 0:23:15.920 demmer switches worked on the principle of a variable resistor. 0:23:16.280 --> 0:23:18.960 So a resistor is an element in a circuit that 0:23:19.119 --> 0:23:24.040 resists the flow of electricity. It doesn't prevent electricity from flowing, 0:23:24.480 --> 0:23:27.560 but it does make it, you know, harder for current 0:23:27.600 --> 0:23:31.240 to flow through. If we think about it in an analogy, 0:23:31.320 --> 0:23:33.760 like in terms of friction. You can imagine something like 0:23:34.119 --> 0:23:36.960 a floor that has a very rough carpet on it, 0:23:37.000 --> 0:23:38.640 and it would be very hard for you to shuffle 0:23:38.720 --> 0:23:43.440 your suck footed feet across such a floor. And like friction, 0:23:43.680 --> 0:23:45.600 we see some of the energy that used to be 0:23:45.600 --> 0:23:49.240 in one form convert into heat. That heat is lost. 0:23:49.920 --> 0:23:53.200 So a variable resistor is a component that has an 0:23:53.200 --> 0:23:57.200 adjustable electrical resistance. You can change the amount of resistance there. 0:23:57.600 --> 0:24:01.960 Typically you would have a piece of resistive material, and 0:24:02.119 --> 0:24:05.639 you would have a static contact arm. That means it's stationary, 0:24:05.640 --> 0:24:08.000 it's not moving anywhere, and you would also have a 0:24:08.040 --> 0:24:12.199 movable contact arm. Now the stationary contact arm is connected 0:24:12.320 --> 0:24:15.960 to one end of this resistive material, and you know, 0:24:16.000 --> 0:24:20.040