Filter over header to make darker

Hi,

On this theme there seems to be a filter over the header image to make the image appear darker. It is possible to remove this? (Would it be a line in one of the CSS files that I have to remove?)

I would like the grey of the header to match the grey of the top left box. It is actually the same image cut down, and this is how I can tell there is some sort of filter over the top header.

Many thanks,

Paul

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