When a full Lunar Eclipse occurs, you will see all 3 types of Eclipses one after another.
This was the first type of Lunar Eclipse to happen on the night of April 14th into April 15th 2014.

With a penumbral eclipse, the outer, light penumbral shadow of the Earth begins to cover the moon.
However, this phase of the eclipse is rather subtle.
It appears mainly as a faint shading moving across the moon’s face.

Although my research only found one mention of it, there was a blue ring around the moon during parts of the penumbral eclipse.
Others have said they also witnessed it. That thin ring is most noticeable at the top edges in the photo. Again, it is subtle.

Here is a different photo of a full moon not during an Eclipse. http://www.pbase.com/britestar/image/108076825
You may notice the subtle "change" between that moon and the muted one during penumbral eclipse.

To see the April 2014 Moon during Full Lunar Eclipse, go to http://www.pbase.com/image/155246431