1970s Painting Of Man Coming Through Ethereal Gate Occult Mysticism

One of the strangest and perplexing pieces I have in awhile. 
Not a lot of details to give but the piece comes from an occult collector. 
Not signed on the board, front or back but the mat is noted.

The first thing that comes to mind is William Blake and his occult mysticism inspired art. 
The painting is done on an artist board, but the execution is the strange and with the artist being completely ameature or done in a state of skilled. 
The background is painted a solid brown, the figure and opening are done in a burnt muted yellow. The opening is like an etherial gate opening with the figure coming through. The figure with shadowed features is done with an illustrator's hand. It is like the figure is coming through the gates of time ands thought. 
Sounds far fetched but the collection of books, occult and demonology books, it is easy to be lead in this interpretation.

Size: 11 x 14 inches
Condition: fine with light abrasion on the corners from being mated. A light abrasion going across the bottom can be seen. The paint is very thinly applied over the brown causing a glossy effect. The painting can be cleaned lightly and varnished taking away the uneven gloss. Please contact me if you want an estimate on conservation.Please see the images for more details. 

If you have any questions or need additional information, please feel free to contact me.

Noted:
Over seas buyers please email me for shipping quote, please provide me with a shipping address and postal code.