Posts Tagged ‘chroma’

Color Theory Basics – Saturation and Chroma

Friday, January 8th, 2010

Continuing our discussion of Color Theory we move on from Hue to Saturation and Chroma. These are two closely related but distinct properties of color. Learning these distinctions and understanding them implicitly is what will give us a deep and sophisticated understanding of the uses of color.

In order to discuss these ideas we must first take a quick look at color media for lighting. The three major brands of color filters are Lee, Rosco, and Gam. Each of them produce similar but importantly distinct ranges of colors. Regardless of the particulars of the color media they all operate in a similar manner.

Clear incandescent light emits a range of colors in the visible spectrum. In fact, it is that range which makes us perceive it as White light. A color filter is precisely that, a filter which eliminates all excess wavelengths to allow only those wavelengths desired by the designer to get through. A filter like Lee 201, for example, pulls out many of the wavelengths along the Red and Amber end of the color spectrum to give a clean 5700° K color. We will get more in depth on Color Temperature and lighting design in a later post. But for now it is useful to know that L201 is a pale Daylight color.

If Hue is what we would commonly call the color, then Saturation and Chroma deal with different aspects of brightness. Saturation is how much of a given Hue might be found while Chroma deals with where that Hue falls in a spectrum from Gray to full Chroma. Let’s look at Saturation first.

Saturation is how much of a given Hue is in the filter. Low saturation is closer to White light and colors in that range are called Tints. High saturation has a lot of one particular Hue, are very chromatic, and we call colors in that range Shades.

Tints tend to allow a lot of light to pass through. It can be tempting to forgo heavily saturated colors, particularly deep and rich Congo Blues, because they allow so little light through (1-4% typically) that one might easily choose a lighter saturation for greater transmission. It is important to not be afraid here. Bold color choices demand a degree of risk. Even though there is such a small amount of light actually getting through the filter, the effect can be quite strong. If you need the saturated color, use it.

Since we looked at very saturated and chromatic colors in our exploration of Hue I thought it would be nice to look at some Tints this week. On the left you will see the Rosco CTB filters. You can see the colors ranging from nearly White to a nice middle Blue.

You will also note that while the Hue of these colors is a Blue, they tend to fall closer to Gray than a purely chromatic color. Thus we see here an example of variance by Chroma.

Below we have a low saturation Red, commonly referred to as Pink. What is interesting in this image is the spectral analysis of the filters. The black curve in each image shows us how much of each color in the visible spectrum is contained in the filter. You will note that while the warm end of the color spectrum, from the end of Yellow through Red, remains the same we see a marked shift in the middle Blues through Green and into Yellow. This allows us to see not only how much color is filtered out but also how each filter relates to the other one.

On the right hand side of the picture we see the manufacturer’s name and number for the filter. Then below that is the Transmission. This tells us how much light passes through the filter. The lower the Saturation, the higher the Transmission.

Because all color is relative, nothing is objectively a Tint or a Shade. Comparing G108 and G105 we see that 105 is a Shade of 108. Yet compared with a solid Red like G250 we see that G105 is also a Tint.

We will go much more in depth on the relativity of Tints and Shades when we cover Missing Color Syndrome in the next part of this series. For now, let’s move on to some practical applications.

Returning to our example of the Woman-in-a-Red-Dress we can immediately see an application for color of differing saturation, yet utilizing the same Hue. Our woman enters and the lights change. We turn on a Frontlight special in G250 but immediately notice that while the dress looks fantastic, our Woman has turned rather garish. Loving the dress, but hating how our actor looks, we decide to turn on our G108 Crosslight. The effect now is of a deep red dress with rich and brilliant shadows sculpted by a pale Pink Tint. Because of the G108, our actor’s skin looks beautiful and healthy. We have just achieved a happy costume designer, a happy actor, and a happy director. All with some simple color tricks.

Beware: death by Tints.

While the proper use of tints, as we see above, can be a real life saver, they can also cause us unbelievable headache. I have seen plenty of Yellow and Pink costumes ruined by a “why bother blue” that had just too much Green in it. Colors, and by extension actors, can disappear in what appears to be white light all because of a tint we did not pay enough attention to. Healthy actors can look sick because that Amber front light we fell in love with in the studio has just a hint of Green.

Knowledge of Saturation is a useful tool in the designer’s tool kit. Without such information, our Woman-in-a-Red-Dress would be left looking like some freakish alien, instead of a stunning ingenue. Using Shades to fill in shadows and Tints to highlight can be a great way to sculpt a figure with color.

We need not use the exact same Hue either. G250 which falls pretty solidly in the Red camp could easily be paired with sympathetic colors in tints. Instead of the Magenta and Amber I proposed in the post on Hue, one could use Tints like R53 (a Lavender) and R302 (a pale Rosy Amber).

A solid understanding of Saturation and Chroma will allow you to really start mastering the use of color. If you missed my post on Hue I would encourage you to go back and read it through. In later posts I will be exploring Missing Color Syndrome, Dominant and Recessive Colors, Color Correction, Gray, The Effect of Lamp Type, and Additive vs. Subtractive Color Mixing.

I hope you found this useful. Please take any new ideas and start experimenting. We will continue to build on these concepts throughout this series. Stay tuned.

Was this useful to you? Please let me know what you thought in comments. Or leave any questions you may have and I (or other commenters) would be happy to answer.

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Color Theory Basics – Hue

Monday, January 4th, 2010

Our discussion of color theory begins with a look at Hue. Hue is the most basic element of a color and what most people think of when they think “color.” Hue refers to the specific wavelengths of light which hit your retina and cause you to experience sensations like “red” or “yellow” or “green.” Because this is such a foundational element of color theory this post will be a bit long and involved. But it’s worth it!

While the colors of pigments and the colors of light are all the same, their relationships differ between mediums. Primary and Secondary Colors differ when discussing pigment or light. The relationship of these colors, as well as what you can mix to make which colors, vary depending on what medium you are using. The first rule of color: Everything is Relative.

We have all been introduced to a color wheel at some point in our lives. The color wheel is a visual representation of colors and their various relationships to one another. To make a color wheel we draw a circle and then divide it into six even sized wedges. We fill every other wedge with the three Primary Colors; Red, Yellow, and Blue. With the remaining three alternate wedges we put in our Secondary Colors; Orange, Purple, and Green.

Primary colors are those which can not be mixed together through the use of other colors. Secondary Colors are a combination of equal parts of two Primary Colors. Thus Red+Yellow=Orange, Yellow+Blue=Green, and Blue+Red=Purple. The formula of combining colors follows to create Tertiary Colors and so on. The mixing of all these colors will affect both the Hue and the Chroma. Chroma is where the hue lands in a range of Gray to pure Hue.

Special Note: Modern printing techniques using Cyan, Magenta, and Yellow (and Black) seem to indicate that this traditional view of color pigment relationships is incorrect. Cyan and Yellow ink, for example, combine to make Green.

With all that said, here is the traditional color wheel we all learned in elementary school art class:

When we mix all three primary colors together in equal parts we get Black. In theory. In reality you tend to get a dark brown and can actually create some wonderful variations in brown by slightly altering the proportions of the different colors used.

The behavior of light is very different. The primary colors are Red, Green, and Blue. While the secondary colors are Cyan, Magenta, and Amber (Yellow). With light Red+Green=Amber, Green+Blue=Cyan, and Blue+Red=Magenta. Not only that but an even mixture of all three primary colors produces White light. In theory. In reality one tends to create shades of Gray.

The lighting Color Wheel looks like this:

It is interesting to note that if we replace the traditional pigment color wheel with the revised one based on CMYK printing we discover that the Primary and Secondary Colors of light and pigment are not just different, but are totally inverted. We can use this to our advantage by turning brightly colored surfaces black with differently colored light as I will discuss below.

The effect of Hue variation on the color of Costumes and Scenery can be tremendous. By knowing the relationship between the Primary and Secondary colors you can create striking effects. What I call “Sympathetic Hues” are colors in light which contain elements of, but are distinct from, the Hue of a Costume or Scenic piece.

Let’s take the classic Woman-in-a-Red-Dress. When she enters at the top of the staircase we really want her to shine. As such we would use colors on the dress which are sympathetic to, or enhance, the dress color. In this case we could use a red like the dress. If we wanted two colors from opposite sides we could use a combination of colors like Magenta and Amber. Here we see the Hue of the light is making the intent of our collaborator (the Costume designer) stronger by reinforcing her bold color statement.

The drawbacks of this are that we could ruin the designer’s intent. This typically happens with heavily saturated light and delicate or intricate costumes or scenery. The color becomes so dominant that we lose the pattern, which may have been for a particular design purpose. One of our primary jobs is to make our collaborator’s work look the best it can (and how they intend it to look!). A deep understanding of color will allow us to do that.

Another drawback to such a broad statement would be the light on the performer. I don’t know many people in real life who have saturated red skin (or blue or green). So while the color might be the right idea for the dress, it might not be the right idea for the performer. The Woman-in-the-Yellow-Dress should not look jaundiced, for example.

A color whose position is opposite another color on the wheel in known as a “Complementary Color.” Complementary colors can create striking and dynamic effects when placed next to one another (or in lighting, when coming from opposing angles). This strength does a curious thing when a pigment is lit with its compliment. A Cyan floor, bathed in Red light, will appear Black to the human eye. We can use this to great effect by obscuring a scenic element until just the right moment of revelation. The risk, of course, is in destroying our collaborator’s intent by deadening the colors of their impeccably designed scenery.

Here we can see the relationship between compliments:

In addition to Primary, Secondary, or Complementary Colors we can also group Hue into one of three categories; Warm, Cool, and Neutral. Warm Hues include Red and Orange. Cool Hues include Blue and Cyan. Neutral Hues include Green and Magenta.

Warm, Cool, and Neutral are not absolute, but relative. In our example above, the red dress is treated as Neutral while a Cool Red (Red with a little blue, but not so much as to be Magenta) light might come from one side and a Warm Red (Red veering towards Amber, but still clearly Red) from the other. In this way we have the effect of complimentary colors (Blue and Yellow) creating a striking effect, while using only Hues which are sympathetic to the color choice of our collaborator.

One final word on Complementary colors and light is worth noting at this point. If you have a single source of light, say the sun at midday, which casts a shadow, the color of the shadow is the complementary color of the light. While this can be hard to see with something so subtle as sunlight, try it some time under a Sodium Vapor (Orange) street light. The shadow should have a faint tinge of Blue or Cyan.

This color effect can be used to the designer’s advantage in myriad ways. One could simply exaggerate the shadow color on stage through a hard directional light in one’s chosen Hue and a soft diffuse light in the shadow color. Alternately this idea could be employed by choosing opposing colors of Head Hi booms.

One of the most famous uses of this color effect is in the lighting method outlined by Stanley McCandless in his A Method of Lighting the Stage in which he suggests using Diagonal Frontlight in complementary colors from opposite directions. His “warm” and “cool” area lights could easily be made more specific using this knowledge of the shadow color of a light.

Hue is a foundational element to our understanding of color but it is by no means all there is. In later posts I will be exploring Saturation and Chroma, Missing Color Syndrome, Dominant and Recessive Colors, Color Correction, Gray, The Effect of Lamp Type, and Additive vs. Subtractive Color Mixing.

Stay Tuned!

I hope you found this post useful. Please take any new ideas and start experimenting. There is a lot more to cover on Hue alone and I may do so in later supplements to this series.

Was this useful to you? Please let me know what you thought in comments. Or leave any questions you may have and I (or other commenters) would be happy to answer.

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