This is the first in a seven photo project about 'blank'.Answers.com defines blank as follows:
   

   

adj., blank·er, blank·est.

1. 
   
   1. Devoid of writing, images, or marks: a blank page; a blank screen.
   2. Containing no information; unrecorded or erased: a blank tape; a blank diskette.
2. Not completed or filled in: a blank questionnaire.
3. Not having received final processing; unfinished: a blank key.
4. 
   
   1. Lacking expression; expressionless: "Although his gestures were elaborate, his face was blank" (Nathanael West). See synonyms at empty.
   2. Appearing or seeming to appear dazed or confused: greeted me with a blank stare.
5. Devoid of thought or impression: a blank mind.
6. Devoid of activity, interest, or distinctive character; empty: tried to fill the blank hours of the day.
7. Absolute; complete: a blank refusal.

n.

1. An empty space or place; a void: During the exam my mind was a blank.
2. 
   
   1. An empty space on a document to be filled in.
   2. A document with one or more such spaces.
3. A manufactured article of a standard shape or form that is ready for final processing, as by stamping or cutting: a key blank.
4. A blank cartridge.
5. Something worthless, such as a losing lottery ticket.
6. A mark, usually a dash (-), indicating the omission of a word or of a letter or letters.
7. The white circle in the center of a target; a bull's-eye.

v., blanked, blank·ing, blanks. v.tr.

1. To remove, as from view; obliterate: "At times the strong glare of the sun blanked it from sight" (Richard Wright).
2. To block access to: blank off a subway tunnel.
3. Sports. To prevent (an opponent) from scoring.
4. To punch or stamp from flat stock, especially with a die.

v.intr.

1. To become abstracted. Often used with out: My mind blanked out for a few seconds.
2. To fail to find or remember something: I blanked when asked the name of our mayor.
3. To fade away: The music gradually blanked out.

The blank space you don't see is a window between the sun room and the living room.
                  

Its blankness reflects what is on one side and allows a view of the objects on the other side.

            

In both these pictures, the stained glass piece is hanging in a window behind me.

The baby bed is in the room in front of me.  

 In some ways our eyes work this way.  

We see what is on the outside, but our view is colored by what is on the inside.