Black darters at Cragside

I went looking for dragonflies at Slipper Tarn in the Cragside Estate, hoping to find black darters.  The one in the photo above is an immature female and the two below are mature males.

There were a lot of immatures such as this male below.

These are teneral (newly emerged) males.  They have very shiny wings with transparent veins.

And this female is so new she hasn't fully expanded her wings.