Sounds like you are not adjusting your blend states before you render them. Meaning that whatever the base image colder is will be lended though to your new light render.
`//Blending states
private BlendState lightBlendState;
private BlendState linierBlendState;
lightBlendState = new BlendState
{
AlphaSourceBlend = Blend.One,
ColorSourceBlend = Blend.One,
ColorDestinationBlend = Blend.One,
AlphaDestinationBlend = Blend.One
};
linierBlendState = new BlendState
{
AlphaSourceBlend = Blend.BlendFactor,
ColorSourceBlend = Blend.BlendFactor,
ColorDestinationBlend = Blend.BlendFactor,
AlphaDestinationBlend = Blend.BlendFactor,
BlendFactor = new Color(0.5f, 0.5f, 0.5f, 0.5f)
};
Then later just call the following before you draw the Lights. Or just use the default built in states.
graphics.BlendState = linierBlendState;