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In this chapter we are going to look at Gamma Correction.
So you will be able to understand what Gamma Correction is because it's very important.
If you don't use Gamma Correction in 3ds Max then what's going to happen is your
renderings are going to look really washed out.
So what I have done here is I have opened up this photograph that I have taken
of San Francisco's Mission neighborhood and we are going to just add an
adjustment here so we can sort of simulate the way that Gamma Correction works.
Now you don't need to necessarily follow along with this, but we are just going
to take a look at it. So here we go. I am going to add a Level adjustment to this
image by clicking here to add a Levels adjustment.
And this center slider is the Gamma of the image.
Gamma is the contrast curve of an image. And right now it says it has a Gamma of 1,
which means that no change is being applied. If I drag this slider over to the right, reducing
the Gamma to a fractional value, you will see the image becomes apparently
darker and muddier. If I drag the slider to the left, increasing
Gamma beyond 1, you will see that it becomes lighter and more washed out. Okay.
So what is this all about? Well, basically images and display devices
and capture devices all have Gamma correction built into them, so that when you
view an image on your screen, for example, it will be at the correct brightness.
Just as an aside, the Gamma setting for a standard television or computer is 2.2.
If you are on the Macintosh, the default is 1.8.
So in fact, you should probably set it to 2.2 if you are on the Mac.
Image files stored on your computer have a Gamma setting built into them, and
what that does is it essentially compresses information in the shadow areas
where we are most likely to not notice. So that's fine for viewing an image on the
screen but if we wanted to apply this to a surface and render it in mental ray,
then mental ray is going to have to be told that the image has a certain gamma in
order for it to be able to "uncompress that information".
So in other words, we need to set gamma in 3ds Max if we want our textures to
be the right contrast. And so that's a basic introduction to the
concept of Gamma. Next we will take a look at 3ds Max and how
to set the interface correctly in order to achieve the desired results of good
contrast on our textures.