@kjarn The mirror is flat on the table and the black card at the back. It was side light from the window but I had the blinds drwan to stop too much reflection from the window. In Lightroom I then brought up the black to make sure it was all black. I cropped out the edge which was showing. It takes a while to get it positioned right to make sure you are not picking up other things in the shot. It is a big wall mirror that fits the top of the table. I keep it it my study and love using it for reflection shots.
@kjarn Just thought - I also take the shot into Photoshop and clone out any dust drops or little bits that show up - or even a little reflection. I find the black shots always need to be cleaned up a bit. I use the same method with white card at the back and then use flash to blow out the white. Hope this helps.
@kjarn Kathy the dragon is standing on a mirror with black card as the backdrop.