I don't know if this is possible or not, but what I want to do is change the ambient material on figures on a massive scale.

Most of the time everything in the scene or at least most of it.

Is there a way of changing all of it at one time without having to go to each texture zone and changing it manually?

thanks for the help. 

The information is not thorough enough.  Are you specifically interested in changing the ambient value, i.e., setting it to zero, or actually connecting an image map node to the channel.

Specify which Poser version you are using.

I'm looking to just change the ambient to white or a light gray. It's the only thing I need to change in the texture settings but I need to do it for many items in the scene.

Obviously, this can be handled by Python Script, but I haven't seen any specific script which addresses changing the Ambient Color chip. 

Dimension 3D's "XS" (eXtended Shader Manager), is what you want: 

"Copy and paste is very flexible, you can copy complete materials, single nodes, or all materials of an object. Optionally, it's possible to select the node inputs and/or connected nodes to paste. Complete material sets of an object can be pasted to any object that uses the same material names, e.g. a second instance of this object. A material can be pasted to several materials at once. Nodes can be pasted to nodes of the same type or inserted as a new node into a material."

I got it from Content Paradise but it's in the store here.

XS is very useful, however for this type of deal Semidieu's Advanced Material Manager should work well. It's over at RDNA.

Perhaps you could explain a bit more about what you're trying to do ? Ambient is useful in a very narrow range of applications, most of them to do with self illuminated objects and indirect lighting. It is not something you want to change in regular materials in a scene.