LightWave 3D 8 Lighting Wordware game and graphics library phần 6 pdf

white light is “whole” with all the primaries at full saturation. If you remove all the green and all the blue, then you have primary red. Cer - tainly the final color is a highly saturated red, but is primary red a more saturated color than white? White is actually a highly saturated mix of the primaries. However, for the purposes of individual hues, we will accept that any color that moves toward white is less saturated. Value Value works similarly to saturation except that instead of the hue mov- ing toward white, the hue moves toward black. A higher value color is considered to be closer to the pure hue. For example, a pure cyan is con- sidered to be a color of a very high value. If that color were to become very dark, getting closer to black, then that color would be considered to have a very low value. In the business of lighting, value is tied to light intensity, as we know that a light that is colored black emits no light. As a matter of fact, if you set a light to 1,000,000% intensity, set that light’s color to a value of 0, and shine it on a white, 100% diffuse surface, there will be no illumina - tion on that white surface. So, in fact, there is more than one way of setting a final color value. You can set the value in the HSV color picker, you can change the light’s intensity, or you can even change the diffuse value of the surface that the light is shining on. The diffuse value of a surface is a multiplier of how much illumination is applied to a surface. Less illumination means less color transmission to the surface. Less color transmission means a lower final value. ··························· Color Mixing 247 Figure 19.5 (See color image.) Figure 19.6 (See color image.) How Hue, Saturation, and Value Interact Hue, saturation, and value are not completely independent values. They are interlinked through axes. Just like there are x, y, and z axes in LightWave’s Layout and Modeler, there are H, S, and V axes in the HSV color selection model. As you can see in this “color cube” model, color hues that tend toward black have low values, while colors that tend toward white have low sat- urations. Colors that are closest to their original hues have high saturation and high value. Recapping HSV To be clear, hue is simply the base color, the pure wavelengths, whether it be orange, green, purple, or whatever. Saturation is how pale a hue is, with lower saturations being paler and higher saturations being more vivid. Value is how dark a hue is, with very dark colors having a low value and very vivid colors having a high value. Chapter 19 ······································ 248 Figure 19.7: Color model showing the interaction of hue, saturation, and value. (See color image.) The Additive Color Wheel There are a number of different ways of describing what is called the “color wheel.” Some color wheels display only primary colors and their mixes, some display primaries and secondaries, and others run the full spectrum including variations of hues, saturations, and values. The additive color wheel is a simple circle of colors in which a color mixture is created by adding light colors or wavelengths together. This is different from subtractive color mixing. Subtractive color mixing applies to pigments instead of light and refers to what light wavelengths are absorbed by the pigment. By adding pigments together, more wave - lengths are absorbed and are therefore subtracted from the total reflected light. For more on this, read the sections on additive and subtractive color mixing later in this chapter. Figures 19.8 to 19.10 are different examples of color wheels. Each displays the correct orientations and relationships between the colors. The color wheel in Figure 19.8 shows the three primary colors — red, green, and blue — and the secondary colors — magenta, yellow, and cyan — that are created by mixing combinations of the primaries. Where red and green mix, we get yellow, where red and blue mix, we get magenta, and where green and blue mix we get cyan. This is a good way to begin to understand how basic color mixing works when choosing dif - ferent light colors for your scenes. ······································ Color Mixing 249 Figure 19.8 (See color image.) A more traditional color wheel, like the one shown in Figure 19.9, also represents the three primaries and the three secondaries, although I prefer a color wheel that shows the mixing as it actually occurs. For a color wheel that demonstrates all the primaries and secondaries, the one in Figure 19.10 is my favorite. This color wheel not only shows what happens when you mix primaries but also what happens when you mix secondaries together. This color wheel gets to the heart of what light is made of. In the center of this wheel, we see white. White is what I call “whole” light. White light contains all the wavelengths, or colors, Chapter 19 ······································ 250 Figure 19.9 (See color image.) Figure 19.10 (See color image.) in the visible spectrum. Each of the primary colors is an individual part of that whole. So if you mix a secondary color like magenta (which con - tains red and blue) with a secondary like cyan (which contains green and blue) then you have all three pure primary colors. Mixing all three pure primary colors will result in white, providing all three primaries are at full saturation and full value. Primary Colors Considering this is a book about lighting in LightWave, and considering that LightWave does not use the “real-world” RYB pigment model of primary colors, this section deals exclusively with the RGB color model. Primary colors are those colors in the visible light spectrum from which all other colors can be derived through mixing. Primary colors are not divisible into other colors. The graph in Figure 19.11 illustrates the three primary colors in the RGB lighting model and how they might appear in a color transmission graph. The horizontal axis represents the wavelength, shown here both in nanometers and as a color representation. The vertical axis repre - sents the amount of all wavelengths that is mixed into the color. ······································ Color Mixing 251 Figure 19.11: A graphic representation of all three light colors. (See color image.) In theory, primary red, primary green, and primary blue would be only a single spike exactly on a single wavelength; however, in reality it is extremely difficult to produce physically precise primary colors. If you find yourself in a situation where you are mixing primary col - ors for a scene, be aware that “real-world” lighting and “real-world” pigments almost always have mixes of other wavelengths within them. A typical wavelength transmission graph for a theatrical lighting fil - ter (gel), for example, will look something like Figure 19.12. As you can see in this graph, primary blue is only one portion of all the light that is transmitted through this filter. There are related wave - lengths such as cyan, violet, and even green. At the upper end of the spectrum, some red light is also allowed to pass through this filter. In the world of stage lighting, this is known as a primary blue filter. But how can it be primary blue if it contains so many other colors? There are two main reasons. One is that all the colors you use in your design are rela - tive. They are relative to each other and to the scenery. Also, the human eye can easily be fooled into believing this is primary. This filter is close enough to primary blue and contains enough of the blue range of wave - lengths to pass for primary blue by completely overpowering the traces of other wavelengths. Chapter 19 ······································ 252 Figure 19.12: A typical wavelength transmission graph for a lighting filter. (See color image.) What it comes down to is this: One of the main problems with com - puter-generated work is that it often looks computer generated. You can add some error simply by taking care never to create colors, like prima - ries, that are practically impossible in the real world. Don’t be afraid to fudge around with the colors. You will find it adds a great deal of dimen - sion to your lighting. Secondary Colors Secondary colors are created by mixing primary colors in equal propor - tions. If you look back at Figure 19.3, you will see how the primary colors (the large circles) mix equally to produce the secondary colors (the small circles). Tertiary Colors Tertiary colors can be created by mixing secondary colors with their pri- mary colors on either side in the color wheel. You can see now that there are three primary colors, three secondary colors, and six tertiary colors. Intermediate Colors Intermediate colors compose all the other hues that come in between the primary, secondary, and tertiary hues on the color wheel. ······································ Color Mixing 253 Figure 19.13 (See color image.) I find it much more natural and intuitive to view a color wheel like the one in Figure 19.14 as I work. This color wheel demonstrates color mix- ing in action, rather than displaying the individual colors arranged in a pattern, although those examples are good for illustrating the basic examples between primary colors and their mixed results. This color wheel also shows the full spectrum of hues, rather than only specific mixes. Color Harmonies, or Schemes When we think of the word “harmony,” we probably think first of musi - cal notes that sound agreeable together. Color harmonies follow that logic. They are a way of finding colors on the color wheel that will work well together. There are a number of standard harmonies that you can use in your lighting design to create vivid, pleasing, and stylistically strong work. This does not, by any means, imply that you are confined to a set of rules for selecting your colors. These harmonies are principles that can help guide you in your color choices. If you wish, you can dis - card these completely; however, color harmonies are known as effective color selection tools that can greatly speed up your color choice process and at least get you into the ballpark of where you want your final colors to be. Chapter 19 ······································ 254 Figure 19.14: Color wheel showing hues. (See color image.) Monochromatic Harmony A monochromatic color harmony simply means that you have chosen to use a single hue alone. Any choice of only one hue constitutes a mono - chromatic color harmony. You may, for example, choose a single amber light as room illumination. If you have a basement room with no exterior illumination and only a single, bare lightbulb in the ceiling, a monochro - matic color scheme may very well fit the bill. This is not a very exciting, vibrant, or interesting way of lighting, but that does not make it any less valid a color scheme. Your scene may call for drab, dull, boring. Mono - chromatic color schemes are an excellent way of conveying this sort of feeling to the viewer. ······································ Color Mixing 255 Figure 19.15 (See color image.) Figure 19.16 (See color image.) Complementary Colors Complementary colors are two colors from the color wheel that are directly opposite each other. If, for example, you chose primary blue as one of your colors, the complement to that color would be yellow. Complementary colors have a high contrast that makes them vibrant and exciting. This system of color harmonies, along with split complemen - tary, is, perhaps, one of the most used color selection systems used in lighting. If you are outside on a sunny day, you are lit with complemen - tary colors. The sun has a yellowish hue that illuminates your face. Within the shadows of your face, however, there are blue hues. This blue Chapter 19 ······································ 256 Figure 19.17 (See color image.) Figure 19.18 (See color image.) [...]... knowledge and understanding and that is by practice Practice your lighting and trust your eye When you choose a color, look at how it plays on the scene and ask yourself how it makes you feel, what, if any, emotional response you have to it, and what sort of mood you think the light brings to your scene If I were an audience member and was shown a scene brightly lit with warm hues of pink and orange,... visible color spectrum Olive green and forest green, for example are considered related tints So are pink and purple Sand and orange are related as well Related tints tend to have a calming effect This is true not only of lighting colors but of pigment application as well If you wish your viewer to maintain a serene vision, avoid clashes or strong complements and go with a key and its relatives Complementary... make it, and what intensity to set You need to equip yourself with a base understanding of color and the effects it has on your scene 272 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Color Mixing You need to understand how the light plays in your scene and what a colored light does to a colored texture You should have an understanding of what different colors and intensities... associated with royalty and wealth Royal purple is one of the favorite shades of purple It indicates wealth and sophistication, containing both the loyalty and trust of blue with the power and excitement of red Black Black can be associated with evil such as black magic and fear or it can denote strength and power Many people prefer black clothing because it gives them an air of control and serenity, others... key and fill lighting This is a fairly typical render, one in which we use a variation of a simple McCandless lighting setup Key and fill lights coming in at roughly 45 degree angles illuminate the full figure with additional highlight instruments placed for warmth and, of course, highlights These angles are selected because they represent a natural light source They make the viewer feel at ease and. .. People feel down and tired On a sunny day though, bright sunlight and dark shadows result in a high-contrast lighting situation People generally feel energized and happy on sunny days Figure 20 .6: High-contrast image Figure 20 .6 is a high-contrast shot Notice that there is a high range between the whitest and the blackest points in the image 2 78 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·... room This lighting gives a sense of wonder and magic to most environments On the other hand, the rushing lights of speeding traffic tend to heighten stress and awareness, giving an edge of fear and chaos to a scene Motions can vary from nearly imperceptible to wild and seemingly uncontrolled It is up to you to use motion in your scenes as you see fit It is up to you to decide whether or not lighting. .. it’s sunny, and the sun is the key light source, the light should probably be 266 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Color Mixing somewhere in the yellow range of the visible light spectrum Relevance is the first technical consideration of your lighting design Following relevance, your lighting must be pleasing I am not inferring that it must be rosy and pretty... complementary, secondary, and tertiary colors will come out differently than they would in the real world LightWave does not support RYB color mixing, so you’ll just have to keep an RYB color wheel handy or make one up yourself There are also many color mixing references available on the web that will help you understand pigment primaries and color mixing, if you don’t already have a handle on them That said,... often in lighting and, perhaps, in pigment selection as well It is very simple and very effective, producing interesting and usually visually pleasing results Triadic Colors Perhaps the first, most obvious use of a triadic color harmony is the use of all three primary colors in a coloring scheme How many children’s toys have you seen that make use of red, yellow, and blue, or of red, green, and blue? . Figure 19 .8 shows the three primary colors — red, green, and blue — and the secondary colors — magenta, yellow, and cyan — that are created by mixing combinations of the primaries. Where red and green. all three primaries are at full saturation and full value. Primary Colors Considering this is a book about lighting in LightWave, and considering that LightWave does not use the “real-world” RYB. Orange and yellow, for example, would be considered related tints. So would orange and red or red and crimson. Red, magenta, and blue would not be considered related tints because, although red and