We have two eyes that are side by side, the space between our eyes is generally the width of one eye. This is where sight becomes complicated.
When we look at an object (especially vertical ones), we see the right hand side of that object with our right eye and therefore see the edge of that form. Straight forward enough so far! Here is the complication - we also see that same right hand side of that same object with our left eye, but in order to do this we are effectively seeing round a corner.
The physical layout of our eyes produces the anomaly that all vertical lines on objects are actually slightly out of focus, they are soft! Essentially we are always looking around corners with each eye as you look at it.
Obviously the degree with which we see this depends on how close we are to the object in question, the further away you are the sharper it will become.
Horizontally our eyes are on the same plane, therefore horizontal shapes appear harder. This is due to the fact each eye is seeing those edges the same way.
A common mistake is that many artists paint too many sharp edges. It is an easy trap to fall into, I have written before regarding how we build an extensive memory of objects from around the age 7. We learned about how we see far more with our brain than we do with our eyes, and this is just another example of how ignoring this natural tendency is a mistake. As artists we really need to concentrate on how we really see!
More on the different types of edges soon...
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