His curiosity was aided by the sharpness of his eye, which focused
on things that the rest of us glance over.   One night he saw lightning
flash behind some buildings, and for that instant they looked smaller,
so he launched a series of experiments and controlled observations to
verify that objects look smaller when surrounded by light and look
larger in the mist or dark.”  When he looked at things with one eye
closed, he noticed that they appeared less round than when seen with
both eyes, so he went on to explore the reasons why.

Kenneth Clark referred to Leonardo’s “inhumanly sharp eye.” It’s
a nice phrase, but misleading.  Leonardo was human.  The acuteness
of his observational skill was not some superpower he possessed. In-
stead, it was a product of his own effort.  That’s important, because it
means that we can, if we wish, not just marvel at him but try to learn
from him by pushing ourselves to look at things more curiously and
intensely.

In his notebook, he described his method almost like a trick
for closely observing a scene or object: look carefully and separately at
each detail.  He compared it to looking at the page of a book, which is
meaningless when taken in as a whole and instead needs to be looked
at word by word. Deep observation must be done in steps: “If you
wish to have a sound knowledge of the forms of objects, begin with
the details of them, and do not go on to the second step until you
have the first well Fixed in memory.”

Another gambit he recommended for “giving your eye good practice” at observations was to play this game with friends: one person draws a line on a wall, and the others stand a distance away and try to cut a blade of straw to the exact length of the line. “He who has come nearest with his measure to the length of the pattern is the winner.” 

Leonardo’s eye was especially sharp when it came to observing motion. “‘the dragonfly flies with four wings, and when those in front are raised those behind are lowered,” he found. Imagine the effort it took to watch a dragonfly carefully enough to notice this.

–    Walter Isaacson. Leonardo DaVinci. Simon and Schuster, 2017. Page 179.

****************************************************************

Spend a few hours trying to draw something accurately from life and Leonardo’s comments about seeing the details will ring true to you.   Sketching used to be one of the practices of a well-rounded education.  That seems a century ago; it isn’t any longer.   So when you walk by someone in the park who is sitting with a sketchbook, looking intently at a tree or a stream, your modern sensibility interprets that as an effort to render an exact likeness…your thoughts might be “oh, I could never do that, to get something on the page to look like something in life, I so admire that effort.”  Then you pass by.

But the sketcher knows that a realistic image is not the point.  (Though accuracy matters.)  The point, what is actually happening when a sketcher is working in his book, is he is trying to see.   Drawing is a mode of seeing.  You actually see more because of the need to reproduce what you see, and the experience of seeing more and more and more feels like an awakening.

“More and more and more…” – again, the modern sensibility, reading these words, interprets them as an experience of finer and finer analysis.   ‘More” means more granular, more information about smaller and smaller parts.   This is partly true (and no doubt some of what Leonardo was saying), but the experience we have while sketching is an awakening vision in multiple directions at once, not just toward the smaller detail, but also color, angles, large shapes of light and dark (“value”), and the unique gesture of the object as a whole.   And more.  It is an experience of analytical honing and of wholistic expansion, together.

All this is what I mean by:  “Drawing is a mode of seeing.”