shader diffuse color too dark

I know practically nothing about programming shaders, so I need some very simple help. This is a very basic shader for making a solid color with a specular highlight, targeted at iOS. It works fine except that the color that renders is about half of what I specify in the picker. This isn't the case when I use shaders with textures, so I'm pretty sure it's not my scene lighting being too low. How can I increase the brightness on the input color so it's closer to what it looks like in the inspector?

Shader "Solid Color Specularity"
{
	Properties {
		_Color ("Color", Color) = (1,1,1,1)
		_Shininess ("Shininess", Range (0.01, 1)) = 0.7
	}
	SubShader
	{
		Lighting On
		Material
		{
			Diffuse [_Color]
			Ambient [_Color]
			Specular (1,1,1,1)
			Shininess [_Shininess]
		}
		Pass {}
	}
}