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Science Of Light

You know, we talked originally about the language of light. I mentioned that it's not very complicated and it's not. We've already learned as much as we really need to know for the basics, we know how to create soft light. Now, right? We have a large light source that's diffused, So clouds Big soft box. Great. We know about hard light on what creates that. It's a small light source. It's far away from our subject. We know that soft light works great for color. We know that hard light works great for black and white images. We know that hard light is great for creating shape. We know all these things we know about speculate highlights. We're going to start diving into that stuff so already we have a good foundation to build on. We need to talk about some of the sci fi stuff, and the first thing they want to do is to remember that light light travels at different wavelengths. And because of that different light sources have different colors, and that is actually called color temperature,...

so some lights have a little bit more blue in them. Some have a little bit more amber in them, and it's based on the actual physical temperature of light. Unless you're talking about fluorescence in, that's all crazy science we're not gonna get into. But let's just say it's all of physical temperature that will help us sort of baseline things to help understand this. I actually have a little diagram that I've created, and I'm gonna confuse you a little bit more because there's some color theory that we don't have time to go into. But I'm gonna give you a taste of color theory. Maybe I'll do another creativelive three days on color theory. That would be awesome. Um, but normally, when you think of things that are blue, you think of cool, right? When you describe blue, you think cool. And when you think orange or red, you think warm, correct. Well, that is, that is called an emotional color, and they do not correspond to color temperature, color temperatures. The exact opposite, actually. And so what we have here is we have this little scale. And if we plotted a skill here from left to right, uh, lamps that have a cold temperature start at a low Kelvin value. So Kelvin is it's sort of like a degree Fahrenheit or Celsius. It's Kelvin and it's called Kelvin because the guy who invented it was Mr Kelvin, Doctor Kelvin, And what he did was he took this piece of metal a very specific kind of metal, and he heated it up. And based on the temperature of that piece of metal, it changed colors. And he found out that when it was cool, it was in this amber range, and as it got hotter and hotter and hotter, it became or blue. And you can see this. If you take a match, strike the match and take a look at it. It goes from white to blue toe orange, so as the color are, as the temperature cools down, the color actually changes. And so we put this year. This is a cold color temperature, but a warm, emotional color. The next thing we have here is this little thing here. This is 3200 Kelvin, and that is a standard 3200. Kelvin is a standard of color temperature, and it's normally what tungsten lights are. So tungsten lights are going out of style and they're not being sold anymore in great quantities. But these lights here are tungsten lights, their normal house lamps, and those are almost all at 3200 Kelvin. And so the soft boxes and the hot lights that we're using in the previous section you're really bright. Those are tungsten lights, and they are exactly 3200. Kelvin. They are calibrated to be that. And so when you when you're renting lights or purchasing lights, generally you're going to ask for daylight or tungsten. Tungsten is 3200 Kelvin, and it mimics this. It's sort of like sunrise. It's a very warm light. It's really cool. Are very warm. Very cool. Like as in groovy. Very groovy. Warm light. How's that? Um, And then daylight. Sunny day light right here in the middle is when you have an almost equal proportion of red or amber and blue. That's about 5500 Kelvin. It's about that and studio strobes and the lights that we have shining around us right here in our studio don't have the cameras show these lights up here, but these lights up that air making me light up right now. These are daylight lights. Their balance to about 5500 kelvin. So, depending on the manufacturer, some, uh, speed lights will be about 50. 200. Some movie about 50. 500. Summer 5600. There. That's one thing around there. But, uh, generally 5500 is daylight. 5500 Kelvin. And so when you're when you're mixing light sources, there are these gels we're gonna talk about tomorrow that will convert tungsten to daylight or daylight to tungsten. There's a term that we need to know about. That's called the white balance. And what we're doing is this. I'm gonna draw this out here, um, and what will have if we have the same little chart here? So this is as we're warming up, we're getting mawr and more blue. And as we're cooling off here, we're getting more and more Amber, right? And so what we want to dio is we wanna have an equal balance of amber toe blue, so when they're equally balanced, our camera mixes, isn't it? Sees white. So that's what we want. And so if this is off, we're gonna have something that's a little bit too orange if you ever shot in low light and everything's all orangey. That's why, because the camera thinks that the color temperatures up here when it's actually down here, there's way too much orange in the picture. So what happens is if we sort of put a line across this, we want an equal mix or an equal mix of blue and amber when our color temperature is lower. What we're doing is for actually adding blue for adding or pulling in blue so that the amber and blue match and then when we are doing the opposite when we want to have, ah, nice color temperature over here, we're actually adding in amber to make that match. And the reason that's important to note is if if you just look at this diagram here and you see that color temperature when it's really warm is blue and you go into a light room or photo shop and you adjust the white balance lighter. Well, when you go to the right, it gets more red, right? It's more amber, and so a lot of people when they see this, or like Oh, no, Mark, you're wrong because and you move the slider, it gets red over here. The reason is getting ready is because we're adding in red to balance that out. And when we're pulling it down, adding in blue to balance that out, let me first explain to you some color theory. So you gonna understand how these things work. So, um, the primary colors are red, green and blue, right? I feel like no is red and yellow, right? There's a yellow in there. We'll find out why. It's both so red, uh, red. He has blue green. And so when these three colors are mixed equally, when we have 18% of red in 18% of blue in 18% green or whatever, when they're equal, the camera can go. Okay, That is where white should be when they're mixed equally, you get white. And so all of these targets, what they have is they have an equal mix of red, green and blue, and it will come out actually 18% gray because of another reason we'll find out later on. But it's gonna it's gonna look gray, right? So red, green and blue, equal proportions. Here's how we get them. All right, So what I'm gonna do here is I'm going to actually take some photos. I want to take a picture of these lamps and see how we do now. What I can do right off the bat is I'm just going to keep my color temperature on my camera sets. So I'm pushing my, uh, my white balance, and I just have it on auto White Mountains. So it's just on auto. And for most scenarios, auto, White balance works. Okay, sometimes not. So Okay, so I'm just gonna use auto white balance to start with, and I'm gonna take a picture of these lamps, okay? These are tungsten lamps. I'm going to get this picture, and it's exposed for the lamps. And that looks pretty good when you think we're gonna look next to the lamp so we can look at the screen and it looks pretty close to what that would you be? But let's say I have my white balance set to I'm gonna set this Teoh flash so it flash is 5500 kelvin on this camera. Take another picture. When my white balance is not set correctly, it will take a picture. And this is what you get a lot when you're shooting in a low light situation. So watch what happens now. That's much more orange, right? We can show these things side by side. So now we can see that the one on the left is not as warm as this one. So this one here, we intentionally said, Hey, this is a flash which added more orange to it, and we get it very orangy thing, or we could do some other things, but you get the idea. So, Lex, I'm gonna have you come out here. We're gonna shoot a couple of portrait's. And, John, I'm gonna see if you can help me out in just a second. So, like, I want you to stand, like, close to these things as close as you can get sort of get in there and then look this way at me. Yes, and then even scooch down a little bit. So we're having some weird, shadowy issues here. Boom. L Okay, so this first picture here is horrible lighting, but we're looking at the color, right. This is the color. And it's a very blurry image because I didn't increase. But look at her skin tone. It's correct, right? Her skin is that color. If I put this on auto White balance. We're gonna do the same thing. So scooch down there, we're gonna take a picture with this Lammy watch what happens in auto white balance. Her skin is going to immediately go to much more orangey. You can't even see the different oranges in that. But the comparison between these two and see if I can show you these again side by side notice the one on the right has mawr orange and the one on the left. And so the point is, if you're shooting something like lamps and interiors and you want to fudge it and make it a little bit more warm than actually is you can actually use an incorrect color setting. But when you're shooting something that needs to be color, correct, like a person's face, need to make sure you have a good white balance set what we're gonna do? One more thing. This is my favorite way to set white balance because you have so much control in post production and this is used for when you're in a situation where you're shooting raw so raw files I'm sold on raw. We're gonna talk a little bit about why raw files really impact dynamic range in all kinds of things. Tonality and the darks and shadows. And if you're doing fine art, you need to be shooting around. But anyway, um, this tool will only work when we're shooting it raw. And, um, what we can do with this is this not only tells us about the color temperature, but it also helps us understand the color in the photo. And we can see if we're over saturating de saturating if we're making adjustments to the wrong thing and you'll see that these colors here actually line up to the color sliders in light room. So this and light room were born toe work together, and it is really awesome. So I'm gonna take a picture with Lex, and then we're gonna go in. We're gonna start modifying our color temperature. So for this, Lex, I want you to come out a little bit, and we're gonna use this light right here as our key light, and I'm gonna have you hold this and you're gonna hold it right next to your face. And I'm gonna take a photo and I'm I'm shooting an aperture. Priority mode here and I'm in auto white balance for this is when you shoot raw, you can set your white balance in post production, and it's exactly the same. Is setting your white balance in the camera when you shoot? There is no difference. So that's like one of the Onley things that you can do in post production. That's the same is doing it in camera. It's That's one of the reasons I shoot. We're gonna shoot auto white balance and they're going to fix it in Khost. So the expo disk we fixed white balance in the camera, and that's great for wedding shooters, sport shooters, people that have to get it right in the camera and can't do postproduction. This is for people that have the leisure fixing things in post production. So I'm gonna go where they told me I can't go and shoot over here, and, uh, there we go. So actually, scooch over this way just a bit there. Thank you. So I'm gonna get really close here, and I'm gonna focus on the color checker and we got that. All right, let's let's talk about this color checker and how it works. And why it's so amazing. So in light room, when we have this image, I'm gonna go into the develop module on the right hand side, you can see that we have this color checker the top part up here. These thes squares here are calibrated for controlling tonality and color. The bottom half is for calibrating color, and I don't think we have enough time to talk about the bottom half too much. It's for building color profiles and again stuff that should be in a color management workshop. But if you'll notice on the top here we have a little icon of a person and we have a little cut out right there. And then as we go, you'll C plus plus plus, and in the bottom you'll see we have a little photo of a little mountain, and on this side it's like physically and on this side it's sunshiny, and in the middle we have a cut out. So what that means is this square on the left right here? This guy right here is a neutral white balance for portrait photography, and this is a neutral white balance for scenic photography. Normally in portrait photography. You Onley wanna warm up the photo? Very rarely. Do you ever want to cool off somebody and make them look freezing and cold and dead ish? But in, um, in scenic photography, you'll sometimes when a warm up the scene or cool off the scene. And so we have the choice of both. And here's how this works in light room and by the way, an adobe camera raw. You get the same thing as the same engine, you have a white balance color picker. And so if you see right here, there's this little, uh, little guy right there, and that is to select the white balance and postal. Click on that and I'm gonna hover over this. We'll see if I can zoom in to show you and the thing that's important to note. Here are these numbers. Look at these numbers right here. 87.1 88.6 89.8. What it's saying is there isn't an exact same percentage of red, green and blue, but there should be, so we click on it, click instantly. We saw, um, we saw the, uh um the shot of of Lex. She got much much more colorful. Get this color picker here again. Now I'm gonna hover over this one more time. Now look at this. Now that we've corrected the color, so I did was I just clicked on that 88.8 88.8 88.7. So now the mix between red, green and blue is scientifically they're identical, right? So we have perfect color temperature. And if we go down here to this, see if I can make this show up, we can see there we have 88 point are 86.4 86.5 86.4. So both of those are are equal. And then we can see here. We're getting, uh we're getting Mawr and mawr make the scooch over. We're getting the green value and the blue values to change the reds toe change a little bit. And so that is a more pleasing warming for a portrait. CR skin tones just changed. We'll do that again here. These down here for scenic photos and you can see that nothing really changed when I warm or cool there because the sea knicks are more pleasing. Teoh greens and blues Teoh increase the saturation and the color of scenic photography. And the top line is Mawr, um, specific to Portrait's. So deals meaning with the Reds. Notice that all of these things you saturation luminous, which we'll talk about later. Red, orange, yellow, green, aqua, blue, purple, magenta. These colors right here are exactly the same as these colors. Right here they match identically, and so you can do is if you need to change the Reds. You can just grab this little slider here and you can start messing around with the reds there, um, or any of the other colors or for making changes. You can see how that works, but I love this tool for managing color and color temperature to do those things.