header image is dimmed, when text is added

I would like to ad text to my header image, but when I do that the picture is “dimmed” it is quite anoying since the image is no longer as nice and clear. In stead i made a header image with the text in the picture itself – but the the text is no longer responsive. Is it possible clear the dimming function orf will you remove it from the theme. Is it possible to add the possibility of adding css code or custom html code to a picture?

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