This section is dedicated to methods for enhancing the quality and realism of your renders, therefore further getting rid of the stereotypical "3d look".
In the diffusion section I explained how a diffuse map with color value information it would create a leaf that would not
allow lights and translucency to take place properly, therefore creating a more subtle diffusion map would result in a leaf that does allow light and the maps for the translucency to have a better affect on the surface, but that came with a small price witch was a loss of color, now our leaf does tend to look a little desaturated because of it. A simple way to fix this is to take your render on the leaf, create a duplicate of the leaf layer and set it to overlay and adjust the overlay layer's transparency accordingly. The overlay layer will get back some of the leaf's lost colors witch will result in a richer more saturated render. Even with accurate use of diffusion color correction is necessary for most renders.
Just like detailed texturing, lighting setups also play a huge role when it comes to making believable renders. Volumetric lighting can make a big difference in your scenes because even the smallest amount of volumetric light can make a world of difference with the richness of the lighting. Volumetric lights is often overlooked and misused, often times it's only used for indoor scene with lights coming trough a window or things like flashlights. Any sunny outdoor scene would really benefit from a subtle amount of volumetic light but don't over do it, a subtle amount for the main sun light should get the job done.
For this setup I added a noticeable amount of volumetric light with some noise applied and placed a few objects in front of the light source to cast shadows. One of the problems with volumetric lights is that the output render often tends too look over lit. a good way to fix this is to use the overlay trick as well but this time make sure you save the leaf along with the volumetric light in a .tga file with transparency because the amount of overlay may look good with the leaf but it may be a little too much for the background, therefore its better to keep things separated.
Specular bloom is a real world effect it is when an object's reflection of a light source is so bright that it creates a soft
lens flare making a small area around that highlight look brighter therefore creating a glow effect. This can be done in max using a blur effect and blurring the highlights only, there you can specify how bright does a highlight has to be to receive this effect and the amount of blur. Another way is in photoshop to color range select the highlighted areas, and copy them to another layer and apply a Gaussian Blur.
Film grain is also a very important effect, it will make your images look dirtier and more realistic, as you can see the image on the left looks too smooth and clean and the image on the right is dirtier and rougher, it looks more like it was taken with a real world camera. You can add this with a film grain render effect or the film grain artistic filter.
It's very important to experiment with the anti-aliasing samplers, some samplers are better suited for certain situations
than others, like the Catmull-Rom sampler is better than the area sampler (max default) if you want your image to look very sharp and detailed while other samplers are better suited for making softer/blurrier renders, I strongly advice you to experiment with all of them under different settings therefore you will now witch sampler to use and when not to use it. As you can see with this image, the Catmull-Rom sampler is better suited than the default render in order to make images look sharper and more detailed and that finishes of this section.