The color of the computer (24-bit color, for example), is from [r0,g0,b0] (brightness 0 pure black) to [r255,g255,b255] (brightness 1 pure white), but in nature, the color is far more than this, but whether the human eye or the camera can only accept brightness in 0 and 1 colors, over this range of colors (color overflow) will be clamp between 0 and 1. For example, the sun, we all know that its light yellow is about [r3000,g2800,b2000] about (estimated), but for it is too bright, it was calibrated to white. Also, neither the monitor nor the photo can display a color that is more than 1 brightness, so 24-bit color is enough to display.
However, at the time of rendering, the problem comes. If the color between the two objects does not affect each other, that's no problem, so in Max, the problem is almost forgotten; once the color between the objects is affected, the 24-bit color is not enough, and the most recent Finalrender global illumination relies on the interplay of colors between the objects. So the introduction of the HDRI, in fact, is not mysterious, is the record of the super bright color just.
In Max, the color between two objects is not completely unaffected, if you use refraction or reflection, or translucent, is the color between two objects affect each other, then see the 24-bit color limitations. Two lights, different brightness, rendering out the same, are white, but in such as marble surface reflection is not the same. So we're going to use that super bright color, which is the clamp color of none.
Look at the picture, the white number looks the same brightness, but the reflection is different. Black numbers are the same.
The white number represents its own brightness, and the black number represents the negative brightness, which is darker than the black color, perhaps the super black for surface color or self-luminescence is not realistic, but for transparency or high light mapping, etc. will have special effects.
How to achieve it? In fact it's very simple, there are finalrender can use HDRI, but Max has its own method, suitable for all versions of Max. Do not know that the majority of the program map at the end of an output parameter bar, for no output parameter bar, max prepared output material
This is mainly used to the right output amount, color offset RGB offset; color level three parameters and checksum clamp option.
Color offset RGB offset equals brightness. Which is to add the value to the color.
The color level RGB levels correspond to the contrast, which is to multiply this value by color. 1 is the same, 2 is double.