Last week we looked at the Texture Preview and its anatomy. Think of the Texture Preview as a gateway to the texture. The preview lets you peek at the essential information about a texture. To see the full set of properties of a texture you need to open the Texture Editor and that is done easily by simply clicking on the Gear Menu and selecting Edit. Go head and do it now. There is nothing to worry about. While the menu uses the term “Edit,” nothing will happen to the texture unless you explicitly change its data. You can use the Edit option to simply peek at that texture. Go ahead and peek, we won’t tell anybody.
I’ll give a quick example of the things that we can find when looking at the detail of a texture.
I’m going to load Victoria 4, which works for both Poser and Studio so anybody can follow the tutorial, and then click on the 3_Fingernail material.
The material is of type Glossy and that gives us a few channels to work with. A channel in a material is a “socket” that contributes something to the final look. Each socket has a name, like Diffuse, Specular, and so on. Some of those names can be a bit cryptic but there is really no way around them; we just have to learn what they are and what they do.
The first channel that we will look into is called “Diffuse.” The term diffuse should not be interpreted as something that “spreads out,” and loses definition. Diffuse is the channel that gives the “base coat” of color to the material. This base coat can be anything: solid color, an image, or a program-generated pattern—also known as a procedural texture.
The Diffuse channel for the face material has one texture of type Image Map. We click on the gear menu and select Edit to load it in the Texture Editor.
Anatomy of an Image Map
Reality gives you full control of the image map’s properties, and you can affect the final render in many ways by simply acting on the properties in the editor. Most of the times you don’t need to do anything, but here is where you get to change the brightness of a texture, for example.
Let’s see all the options starting from the top.
An image map can be treated as a color or grayscale image. The selection is done via this dropdown menu. If we select grayscale then we can select what RGB channel we can use to create the grayscale. To understand this we have to understand how RGB works. The term means Red Green and Blue. RGB is how our eye sees the world: each color is a mix of some red, green, and blue. The computer implementation of RGB uses a number from 0 to 255 to indicate the level for each color component.
If we think to extract just the values for the red channel, for example, and create an image from that, we would have a grayscale image. If this is puzzling for you then let’s think about it. We only have a numeric value from 0—black—to 255—pure white. The only way we can represent this as an image is if we use shades of grey. There is no color data.
The grayscale for red is different from the one in the blue channel, or the green channel. Here are the three channel side-by-side:
We can use any of the channels that we want, or select the Automatic option, which will generate a grayscale image using an algorithm to average the channels.
If this image is used for the bump map channel then we have the option to flag it as a Normal Map. For any other channels channel that option makes no sense.
Next comes the name of the image and its preview. At the bottom of the preview we get the size of the image in pixels. In this case it’s 1024×1024, also known as a 1K image. Remember than in the computer world all numbers are expressed as powers of 2 and not as powers of 10, so we have 1024—or 2 to the power of 10— instead of 1000. Of course we can make images sized at 1000×1000 but they will not align in memory as neatly as 1024×1024. It’s a matter of efficiency.
The other properties of the image are rather technical. They are good for people who really are into complex material definition, and they are there because they need to convert similar properties from Poser and DAZ Studio.
But there is one property that is very useful for everybody and that is the Gain. This property controls the brightness of the texture. The value of 1.0 means that the image is used as it is defined. Anything less than that makes the image darker, and anything higher than 1.0 will make the image brighter. Be aware that a little goes a long way, so avoid making big changes.
One way the gain is useful is to make the “eye white” brighter without having to resort to Photoshop. If you have a texture for the eye sclera you can set the gain at 1.2 and the render will have a much brighter, but still natural-looking, eye white.
I hope this was helpful. We welcome your feedback so please leave a message in this page, if you feel inclined to do so.
Next week we will look at the other channels of the material and learn what they do.