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View Full Version : The Human Eye is a Funny Thing


walden
04-18-2002, 04:48 PM
I am painting an outdoor still life with strong light/shade pattern-- partly from a plein air sketch I did, partly from a photo, and partly from going out on my patio to look at the scene periodically. Anyway, I have been fiddling with the light/shade areas on the concrete & wall, going back and forth as to how much value difference I should put there (basically, overworking that area pretty badly. ) Finally, in frustration, I took my little plastic 10 increment value scale outside and ran some tests. When I laid it on the floor right on the dividing light between sun & shade, and tried to look at it such that I had equal amounts of sun and shade in my field of vision, the sun & shade areas were only a single step apart. When I sat in the sun and held up my value scale to the dividing line from a distance of 5 or 6 feet (sun wasn't directly on scale), sun & shade areas were 4 steps apart. When I sat in the shade & tried to do the same thing, I couldn't measure it because the light was, of course, lighter than the lightest light on my scale. Weird huh? No wonder I can't get this stuff straight. And that's before I even start to THINK about color and temperature of light and shadows.

This art stuff AIN'T EASY. :D

DraigAthar
04-18-2002, 04:52 PM
I can totally sympathize, Walden. I just spent the last hour fussing with a little patch of grass and it STILL doesn't look right. I'm ready to give up! Heh.

bruin70
04-19-2002, 02:42 AM
what are you talking about? i think i could explain to you what was happening if i knew what it was that was troubling you....{M}

walden
04-19-2002, 06:33 AM
Oh, thanks, Milt, but I think I understand it-- it's just that I had never studied it so closely or run experiments. It's the dynamic range of the human eye. I had tended to think of the value difference between sunlit and shaded areas of a plane as a relatively fixed difference, which is just completely untrue. It depends completely on the adjustment of the viewer's eye. And, I didn't realize how dramatically and quickly our eyes adjust to the amount of light in the scene. When I got very close to that dividing line between sun and shade, and attempted to make my field of vision half light, half shade-- it wasn't really. My eyes were adjusted really towards mostly shade, which meant that I saw the value difference as small, and saw lots of colors and values in the shade areas. So, if I want to convey a close-up scene that is mostly shaded, but with a few patches of bright sun, I can do that most effectively by keeping that value difference small, but accentuating the shadow/light effect with color temperature. On the other hand, if I want to convey a mostly sunny scene with a few patches of shade, I can best do that by increasing that value difference between the sun and shade areas.

I have never formally studied art, just read a lot of books, looked at a lot of art, & painted a lot. Some of these things that people like me discover like this are probably incredibly obvious to someone who HAS seriously studied art-- but they're really big, strange revelations to people like me. :D

bruin70
04-19-2002, 04:20 PM
Originally posted by walden
,,, My eyes were adjusted really towards mostly shade, which meant that I saw the value difference as small, and saw lots of colors and values in the shade areas. So, if I want to convey a close-up scene that is mostly shaded, but with a few patches of bright sun, I can do that most effectively by keeping that value difference small, but accentuating the shadow/light effect with color temperature. On the other hand, if I want to convey a mostly sunny scene with a few patches of shade, I can best do that by increasing that value difference between the sun and shade areas.



the "value difference" between light and shade are not very different. in both your examples, larger light/little shade and larger shade/little light,,,the "little light/shade" can both be considered accents when you emphasize it's larger counterpart. and,,,as accents, you can exagerrate their value to make a point.

in fact, my approach is quite the opposite of yours. when i want to show a shaft of light bursting into a shaded area here is what i think,,,, i see all the subtleties of value in the shade, suddenly this light HITS the ground. it SLAPS the shade with a SMACK of light. ie,,,darken your room by closing the draperies, then open a crack of light in the draperies. watch the DIRECT light hit the floor. watch it hit a vase or table or other object. you will note,,,i said "hit", because that is what it does. the light SMACKS the floor, it SMACKS the objects. it is a harsh intrusion on the subtle values of the shade.

because you see,,,,in the examples you mentioned, your eye sees all the detail where the larger area is. it adjusts to the dominating area, leaving the smaller area as accents. in a large light/small shadow scenario, the pupil contracts to tiny, making all the shadow appear very dark, losing all detail. in a large shadow/small light scenarion, the pupil opens up to accomodate the value detail in the shadow, and the light appears very bright, losing all detail. in the latter, this is why light appears to SLAP the floor or object. it is harsh and bleaches out all detail.

i think what is happening to you is that you are actually shifting your vision to accomodate the light, so you see a softer transition. if you focus totally on the shadow, the light would be viewed peripherally, and thus be seen as harsh accents.

from an artistic point of view,,,and this is where it REALLY counts,,,,,you don't want to show detail in everything because all that detail would fight for your attention. so,,,you pick what you want to emphasize, what's in light or what's in shadow, and de-emphasize the other by pushing it to extreme. from a PRACTICAL artistic point of view, why place attention on a small area of the whole.

look at this sargent. http://sunsite.dk/cgfa/sargent/p-sargen38.htm

let's concern ourselves with two lights here. the harshlight slapping the floor and the incidental light on her dress. see the difference in effect. now,,,,you and i know that the floor is not as light as he paints it. however, in the context of the painting, sargent wanted to emphasize the sharp smack of of the light on the interior floor.

having said all this,,,, and once you understand it, by understand i mean apply it's principles artistically, you can put all this in the back of your mind and now play with the concept of "manipulating as you see fit"......{M}

walden
04-19-2002, 07:33 PM
i think what is happening to you is that you are actually shifting your vision to accomodate the light, so you see a softer transition. if you focus totally on the shadow, the light would be viewed peripherally, and thus be seen as harsh accents.

I didn't think of that-- that could very well be true. Hmmm.

having said all this,,,, and once you understand it, by understand i mean apply it's principles artistically, you can put all this in the back of your mind and now play with the concept of "manipulating as you see fit"......{M}

Yeah-- as I (over)worked my painting, I went through a wide variety of values in both the lights and the shadows, and it struck me how many different BELIEVABLE combinations there are. First and foremost, I want my work to look like it could really happen that way in real life-- after that, I think about the feeling, the statement I'm going for. Well the universe of "believable" or "right" is really large, so maybe that's something I should worry about less, and put more and earlier focus on my statement. The viewer WANTS to believe, and their mind and eye will help a lot.

I will think about this effect and study it some more. Thanks!

djstar
04-20-2002, 02:46 AM
WOW Milt, I am getting all humble (like I ever had reason not to be) after that JSS! I guess somehow I flipped past that page!
I think I will have to study it for a few hours.
Just when I am feeling like I have a handle about a few things, new wrenches fall into the works.

I LIKE the idea of that your eye is paying attention to larger areas.
A smack of sunshine and a dark hole in a doorway.
The intrusions into our attention.
The precision is sort of like the amount of time you have to be aware or the sudden impact it has on the visual moment.
Very fourth dimensional ideas.
Love thinking too much just before I go to bed!!!
dj*

impressionist2
04-20-2002, 09:28 AM
Milt, I had to read your post twice to understand it. Fascinating and filed. What a great image example.

That image link stalled and I brought up another site with a Sargent Tour in the Boston Museum with some interesting sidenotes. Renee:


Venetian Interior - c. 1880-2

"This is an evocative example of Sargents mastery of light
and the boldness of his brush work. A single slash of
pigment brings a ray of intense sunlight into this darkened
room, although we can clearly feel the bright exterior sun
just beyond the window. Look at how he gently bounces
sunlight across the shining floor. Single brush strokes
deftly define a mirror and the edge of a door. What are the
ladies doing here? Who are they? It is suggested that they
are bead stringers. Sargent , ever the puzzler, leaves us
wondering.

This piece was accompanied by an a capella choir singing
some glorious aria or Italian love song, I don't know which,
but it was the perfect blend of image and song which left
me overwhelmed with bliss. You had to be there."


The whole tour ( although the images are dark, but the sidenpotes are interesting.)is at:

http://members.tripod.com/~BDenda/Sargent1.html