In WED the lowest possible ambient I can set is -100. How I can make my objects darker, for example like ambient -200? Is there any material or something?

sun_light =0;

look at mtl_shaded
http://www.conitec.net/beta/amaterial2.htm

read up on materials and how to adjust them

Thank you for response.
I don't understand how use mtl_shaded for this, it's for blocks. I only want make darker some specific models in level, without changing sun or something else in my level. Example, I need some material which will increase ambient value for *2. Is there anything like that?

U checked out the ambient values in MED Skin / Settings?

well you didn't read up on materials. Yes it says it is used on blocks , it not limited to being used on blocks . in fact there is nothing special or different from mtl_shaded and mtl_entity expect the value settings. like rayp said look at first checking the material box on the med skin and adjust the models material and like i recommend spend a few days reading the manuals in all places about materials and then test and experiment tell you understand how to adjust and use a material for your needs.

Or maybe someone will have the exact answer you need and will post it.

also you seem to be confused about increasing ambient and making things dark . at 100 ambient (increase ) it will be muck lighter the the rest of the level. Ambient is a light color that effects everything separate from the sun. in affect it is a minimum light level if you reduce or remove the sun light.