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Having discussed color mapping a little bit in theory, and having looked at the controls held in common by the various color mapping options, it's time now to do some visual comparisons between the various color mapping modes. Of course, we need to open up our Render Settings window, so let's go and do that. Let's come along to the V-Ray tab, and let's open up our Color mapping controls, of course. And before we start, we just want to make certain that our Gamma value is set to 1.0; that is how our pre-rendered images were prepared. Remember, you can open up these images, if you want to look at them, you can find them inside of your Exercise_Files folder, or you can use the values we are going to work with here, and just take renders working along with us.
Now, at this moment in time, we are looking at a render taken using the default Linear multiply color mapping mode. This mode will simply multiply the color samples taken by our rays based on their brightness. Now, a big problem with this mode is that it can result in burnt-out spots; bright areas, especially near bright light sources, which I suppose is not surprising, as even the brightest samples in our scene are being multiplied together. You can see this effect very, very clearly beneath our direct light source.
To solve this particular problem, you may want to work with the next color mapping option in our list; that of Exponential. If we just move along in the Render view, we can see we go from this, to this. You can see how we really have tamed down those bright spots in the scene. Now, the Exponential color mapping mode, instead of multiplying our samples together based on their brightness, will instead increase, not the brightness, but the saturation of our pixel values. Whilst, as we can see, this is a good option for dealing with bright spots -- those burnt-out areas in a render -- we may still have a little bit of a problem in that saturation, and increasing saturation, will always push colors towards white, which, in our case, may not be a desirable end result.
To tackle that particular problem, we may want to switch from Exponential, over to HSV exponential, and again, if we just move along in Render View, you can see we would go from this, to this. Now, if you just take a look at the top of this taurus, not the areas around here, you will see that we go from very white looking, or bright looking colors, to ones that don't have that effect in them at all. HSV exponential, as we would perhaps expect, does work in a very similar manner to the Exponential mode, but instead of pushing colors in terms of saturation, which as we say, may move them towards white, HSV exponential will, instead, work to preserve color, hue, and saturation.
Again, though, this color mapping mode may not be without its problems in terms of how our final renders are looking. You can see that we really do end up with an image that looks a little bit flat maybe; a little bit lifeless. These bright areas that we see in the Exponential mode are what we tend to expect in the real world whenever we have bright lights sources, we definitely expect to see bright highlights. But here, you can see that's not really the case. Our image does look a little bit flat; a little bit lifeless. And for this reason, we may want to move along and try the next option in our list, which is Intensity exponential, and if we just go and move along in terms of the renders in Render View, we would go from this, to this, which as you can see, gives us a little bit more life to the scene.
Now again, this mode, very similar to exponential and the way it works, but here the algorithms are working to preserve the ratio of the R, G, and B color components, keeping them balanced, as it were, and infecting instead only the intensity of the colors themselves; not the saturation. This means, as you can see, we get a more expected falloff of the RGB intensity in our render, and as we move away from bright light sources, we can see the values go from bright to dark, which probably looks a little bit more natural to our eyes.
Now, the next two options in the list, those of Gamma correction, and Intensity Gamma, really are legacy settings. These are from older versions of V-Ray that didn't have that Gamma parameter that we have demonstrated to you. So if we wanted to work with Gamma Correction in our renders, we would need to use one of these color mapping options. We have included renders for completeness' sake, but really, when we set the Gamma Correction option, all we get is a replica of linear multiply rendering, and the same is true of the Intensity Gamma mode.
If we move along, you can see; no real changes there. The final color mapping option available to us, that of Reinhard, is actually a hybrid mode that blends between the Linear Multiply, and Exponential settings. The parameter controlling the blend is this Burn Value. With the Burn Value set to 1.0, the resulting render that we would get is 100% linear multiply in terms of its color mapping. If we set the Burn Value to 0, then the resulting render would be 100% exponential color mapping, and of course, if we place the value somewhere in between, something like 0.5, what we get is a complete blend of the two.
So if we move along in Render View, we would get this particular render, which, as you can see, has RGB intensity, doesn't have the problems with our burnouts, and is something that we can slide either way if we want to. We can increase or decrease a little bit our Burn Value to move more towards linear multiply, or move towards exponential if that is what we want. Of course, as our use of the color mapping controls will affect not only the way our images look once rendered, but also to some extent, what we are able to do with them in post-production applications, it is definitely good that we make proper use of color mapping modes; that we make good color mapping choices according to the needs of our project.
In fact, understanding the critical concepts we have discussed in this chapter, although possibly a little on the dry side for some, will definitely go a long way towards helping us make some good choices in V-Ray that will definitely improve not only the quality of our finished artwork, but also can definitely bump up our level of productivity as well.
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