I liked these lines of Ted Kooser. In that same page he writes 'If the light that falls upon what lies beyond is very bright, you see the scene in vivd colors and there is only the faintest hint of your reflection in the glass. if the light beyond the window is faint, as at dusk, the speaker's reflection in the glass is much more prominent. The speaker notices both his or her reflection and the scene beyond.'
The dark shadow of my head on kitchen window is hollow in the middle with the leaves and stems of the bush outside. Feel like invisible man.