A (Somewhat) Controlled Experiment

I completed my third cast painting in black and white at the Grand Central Academy a few weeks ago. It was of a cast of Beethoven's death mask. Here is the result: 

As a comparison, here's my painting of the same cast that I did while studying at the School of Representational Art in Chicago in the Spring of 2007 (before I went to college):

 This is not a controlled experiment because so many variables have changed. The set-up and lighting condition of the casts, my age and whatever experience I've gained on my own and at GCA since then, and the kinds of paints and materials are all different. But to me, what's important are the differences in method between the GCA technique and the SORA technique.

At SORA, the goal was to copy what you saw as faithfully as possible. We tried to get the values the same between our painting and what we saw in life. To do this, we would squint down, use cut out "windows" that would isolate single parts of the casts, and compare the optical values between different areas. At GCA the approach is entirely different. We set an arbitrary value scale from the darkest dark shadow to lightest white highlight, and then judge how dark every area should be not by how dark it looks, but by how much it is facing the light. The areas facing the light source most directly will be lighter than those facing further away from the light source, even if they don't appear that way.

While painting a cast at GCA, I try not to feel like I'm painting, but that I'm sculpting a copy of the cast.   It's a completely different mental process from trying to optically copy the way I did at SORA. I think the differences between the two methods are visible in this comparison.

Final cast drawing finished!

I finished my final cast drawing at the Grand Central Academy. Now I'll be painting casts in grisaille -- a fancy word for black and white.

(For a larger, more detailed photo of my drawing please visit my flickr site).

One of the differences between the GCA method of modeling form and other methods I've been taught has to do with where visual illusions take place. Previously I've been instructed to copy values as closely as possible. The problem with this, though, is that often the values that we see are actually illusory values. Take for instance the visual illusion of Mach bands. Mach bands are strips of light (or dark) that seem to occur on the border between areas of light (or dark) value and the gradient between them.

(Notice the illusory strip of light on the left of  the gradient and strip of dark on the right) 

This illusion happens (mostly) in the retina, due to lateral inhibition of retinal cells. It has to do with ganglion cells being more or less stimulated when part of their receptive field lies on the edge of the value change. I won't go into detail here, but if you're curious this web page gives a good explanation.


I first encountered these as demonstrations of optical illusions in psych class, but recently I found what I think is an example in real life on my cast. See how the bottom edge of lower lip of the neck seems to be lighter than the upper edge? This may partly be due to reflected light -- you can definitely see reflected light from the floor more on the left side of the lip of the neck than the right side -- but look closely within that dark lip in shadow. The part that curves up to the upward-facing area of the chest seems get darker right before it gets light, while the lowest edge seems to have a thin light strip of light right before the dark shadow on the wall.  It doesn't come out well in photographs, but I think much of that experience is probably due to something like the Mach band illusion.

So, if I were to copy values, the illusion would happen in my eye and I'd draw the illusory experience I had on my paper: I would draw the lowest edge of the cast with a thin strip of light, and a darker strip of shadow before the edge turned up into the upward-facing chest area. But I know the value on that shadow edge should be about the same (other than perhaps a bit of reflected light) -- so with the GCA method I didn't draw it, and instead drew an almost uniform dark value on that strip. However, the illusion still happens! (Or it should, if I've drawn it right). It just happens in your eye when you view my drawing, rather than in my eye before I draw it.

(The lowest edge of the cast looks brighter than the middle of that underside lip of the neck, but I swear there's as much graphite there as in the middle of that lip -- and there's no more graphite right before that lip curves up to the upward-facing chest even though it looks a little darker).

It's the difference between drawing my visual experience versus setting something up that will create a visual experience for the viewer. And something about letting the "mixing" happen in the viewer's eye -- setting the stage for an optical illusion to take place, rather than recording an optical illusion -- seems to make the drawing more realistic.

Hair

I spent the last week (or more? It's all a blur) on the hair. Still not done with the drawing, but maybe the two bars of the song "Hair" that I know will now stop rattling around my head.

End of my First Semester at GCA

The Grand Central Academy is on winter break right now.  Here's my drawing as I left it for the holidays: 

One of the most important things I've learned this semester is how closely you can compress the range of values in the light areas when modeling.  Jargon translation! What that means is two different shades of graphite in a light area can be barely different, almost the same way up close, but when you step back a bit, the two shades will look different enough to show a plane break. And by "barely different" I mean "three more dots of graphite". This is useful in practice because it it allows you to anticipate that, though you need to make this next plane darker than the one before, you'll only need a few dots of graphite to accomplish this. The end result will help keep the drawing bright, looking like a white cast, even while shading to show form. I'm still not great at this, and often get critiques that my cast looks "muddy" or "gray," but hey -- I've got it in theory. 

While one of my teachers was explaining this to me, I immediately thought of how this relates to Weber's studies of the just-noticeable difference (called the jnd by psychologists) in the 19th century. The just-noticeable difference is the difference in the intensity of a stimulus needed to be able to distinguish it from another stimulus. Weber studied this in terms of weights: how much heavier must something be so that you can say it's heavier than something else? The interesting point (and one that Gustav Fechner later added to in a quantitative way) is that as the objects get heavier, you need more of a difference in weights to say that one is heavier -- you can tell which of two oranges is heavier when they differ by an ounce, but not which of two bags of oranges is heavier when they differ by an ounce. So the relationship between the stimulus (the actual weights) and the perception (how heavy you feel they are) is logarithmic. This idea applies to many kinds of perception.

In vision, our perception of brightness varies logarithmically with the actual intensity of the light (the number of photons per second coming off that source toward our eyes). I'm not sure whether the application of this fact to drawing in graphite is entirely valid, but it does mean that on the object we're drawing we perceive the drop-off of light into dark (as it turns into shadow) as happening very quickly, even if the change in the number of photons emitted is linear. Therefore a linear drop-off from light into shadow (in terms of number of photons reaching the eye) will appear to be bright for longer and suddenly dark. So it's interesting to think about whether we're re-creating this psychological effect in cast drawing by making the changes in the light areas very small, keeping areas lighter for longer, and then quickly making them darker as it turns into the shadow. 

Phew. Enough science for you?

Third finished cast

This past week I finished my third cast drawing. This one was of a cast of a hand. I'll post a better picture when I get the chance. I took this one under incandescent light at night, which is why it looks so yellow.

 

As part of the first step of drawing the instructors tell us to look for "animal shapes" -- that is, to try to see the shapes not for what they are (fingers in this case) but as animals or characters. This trick allows you to get the shape much more accurate, because you'll notice if a face looks wrong much more quickly than you'll notice an abstract shape is not exactly like another abstract shape.

I decided to outline some of the animal shapes I used when doing the block-in stage of this cast drawing so you can see what I mean: 

At the top we've got Tintin whistling for Milou,who's little white dog head shows up at the bottom running away from a rhinoceros. Can you see them?

Cast sculpture

We work in the sculpture studio for half a day once a week. This week I finished a sculpture of a copy of a cast of the ear.

We have the option to cast our clay sculptures in plaster so we have our own set of casts, but I chose not to this time. I don't want to waste a week doing a cast; I'd rather move on to something else. So I trashed it: it only survives in photographs now. Zen.

Projects in Progress

I've been working on a drawing of a cast of a hand for the past two weeks. Here's the in-progress photos, to give a sense of the working method at GCA. The line-drawing part is called the "block-in." Then we fill in the shadows in one value (called "flattening shadows"). The next step is modelling, which we do by "window-shading": that is, finishing one area at a time and then moving on to the next. I started at the top of the wrist and moved down. Most recently I worked on the two fingers, so those will probably change a bit when I next get a critique.

In the afternoons we were working on doing copies of drawings by Charles Bargue. Here are two pages (out of pages and pages more) for an example:

This week instead of doing Bargue copies in the afternoons we moved on to "tippy casts": one day block-in drawings of casts resting at an unusual angle to really stretch our skills at drawing shapes. Here are two examples I did this week. The first is of a cast of the nose on its side and the second is a cast of the lips on its side. Getting the proportions and shapes correct with foreshortening and perspective like this is really difficult.

The name "tippy casts" really annoys me  though, so my quiet rebellion is to call them "tipped casts." Because that's what they are -- they're not "tippy," they haven't had a Margarita -- they're tipped in an unusual position. Maybe I'm just a crabby old lady, or maybe this is truly an annoyingly cutesy name for such a difficult exercise.