Brightening the colour of a material that can be any colour without shaders.

So basically I have a whole bunch of solid colour spheres and cubes. The colour they are is dependent on the colour of the of the colour the player chooses when joining a game. I have tried adding Color(0.1f, 0.1f, 0.1f) to Material.color but it throws errors at me (it seems I can only set a colour not increase or decrease values. I would be using shaders for highlighted out lines and cool stuff like that but I only have Unity free, not Pro. Can someone let me know how to actually do this please? I have been searching for a while now but nothing I find is of much help at all.

Kindest regards!
Scobbo

My Code:

oldColour = gameObject.renderer.material.color;
		newColour = oldColour + Color(0.1f, 0.1f, 0.1f);
		gameObject.renderer.material.color = newColour;

:EDIT:
I meant post processing, not shaders. DERP

You need to use shaders; for Material.color to work it requires the shader to have a “_Color” property. It’s impossible for anything to be drawn without using some kind of shader, no matter how basic. Using shaders has nothing to do with Unity Pro, you know. Also Unity has a bunch of shaders built-in.