Hi,

One thing that I sometimes notice about some of my renders is that they seem low in contrast, like I've covered the camera with a veil. That's when I hear the music and realize I'm singing the Low Contrast blues.

There are definately times where you want a lower contrast image for artistic reasons, but if you want to push a higher contrast in your render, to give the image more snap, here are a few ideas I've come across. My goal in this is to try and correct a low contrast scene at the source and to avoid using an image editor's Contrast control in postprocess. I'm still a student of these things, so I invite others to jump in and respond -- or correct me as needed.

Seeing it in a histogram
Besides just knowing something looks low in contrast on your own, you can also use an image editing program to see what's going on. Just check the Levels histogram of your rendered image. You can tell if it leans toward lower contrast if the histogram shows a mountainous shape in just one area. That means the majority of your image uses tones in that one area.

A higher contrast image will have a histogram that's more spread out. You can see the difference in the Contrast Example picture below (the lower contrast example is one of my images, the better contrast histogram was from one of Nancy Gormezano's images from the Showcase gallery).

General ideas to help increase the contrast of a render within A:M
1. In the settings for your Lights, set the Darkness to 100%, this will make the darkest part of the shadows black and help fill out the lower/darker tones of the image

2. in your Model's surface properties, avoid using the Ambience Color and Intensity (unless needed for a specific reason). The appearance of shadows on an object will diminish as Ambience Intensity increases.

3. make sure each Light in your scene is there for a reason, and if you have multiple lights or are using a SkyLight, don't throw away the idea of using a well defined Key Light. With one strong Key Light, you can then use and balance all the other lights as Fill Lights, making their intensities low enough so that they don't together add up in intensity to overpower the Key Light.

4. keep the Attenuation setting for your Lights at 100%. In A:M, this setting means the light intensity falls off quadratically with distance from objects which is what you want. Lower values mean the light intensity remains stronger with distance.

This is a start, and hopefully other great ideas will follow this thread.

thanks,
-Jim

Great tips!

I sang the blues with Dave Bowman.

He was a tad "washed out" for 90% of my renders. I had a heck of a time with lighting on him. It was probably the "splash" of a teeny bit of ambience I added for the face and the hair. The hair just kep vanishing to nothing (very very dark) without some ambience... but then it tended to go "flat" with no contrast.

That 80% darkness is another usual cuplrit. Newly created lights will default to that value.

-vern

Vern,

My pitfall is #3. I bring a skylight in and tweak it a bit and I'm like, hey, that looks great! But I don't go further with it and then, there I am again, singing the blues. I'm sure #3 is a whole exploration of lighting in itself -- I mention setting the intensities but there's so much more to cover there. But it's probably helpful to remember that a skylight isn't the lead singer, it's the backup chorus.

-Jim

Thanks for sharing these great tips Jim. Could you enhance your explanation with actual chor. renders?

Huh? Purely by accident, I'm sure.

"I dun no nuting bout birthin' no babies ... er... lighting, Miz Scarlett".

I'm curious, which image?

hi Nancy,

It was totally random! Except for the fact that I was looking for something that looked nicely contrasted. I'd grab an image, look at the histogram, move on to the next... almost like I was working for CSI Las Vegas or something.

Let me look for it again... ah, yes, I was perusing the contest galleries, it's this image you did for the Oz contest:

http://www.hash.com/stills/displayimage.ph...um=36&pos=6

The black in the dress against the white in her face was what caught my eye, then the rest of the image has all sorts of colors and tones in between. But the histogram is really great, you should post it with the image <just kidding!>

-Jim

Dhar,

Good suggestion, I should have posted this in the first place. I realized again that point #3 as I have it is far too simplified because it doesn't take into account ... so many other factors, like the color of the lights, the distance of the lights from the object or the light's falloff, all of these things are factors on how intense the light and shadows appear.

With the example picture I tried to go from low contrast to higher contrast, keeping it simple and sticking to the 4 points I started with:

1. Light's Shadow darkness setting
2. Ambience intensity on the surface properties of an object
3. number and intensity of lights in scene
4. light attenuation

Well said!