This week's demo and topic in Plein Air Adventure was on using the tool of sighting to gauge a measurement, and basing every measurement in your painting from that.
When painting architecture or a boat into the landscape, I often use the tool of "sighting" or "sight sizing" to get the correct proportion and perspective. Please note that this tool is not exact, it's a guestimate. You are solving a visual problem with spatial-relations and not with math.
This is a very important distinction because spatial relational problem solving is a right-side-of-the-brain skill and math is left-side. You always want to be on the right side when painting. This is the visual, spiritual, creative side, and will keep you in the creative flow. When you use math, you pop right out of that flow and into the left side which is the home of perfectionism. This is a dark and scary place that is the killer of creativity. Don't go there!
When we sight size, we often use tools like a pencil, calipers, or a string. Not your typical measurement implements. If you use a ruler, you are using numbers and math instead of comparing this shape to that shape.
Here I'm measuring the height of the tower at Olana in NY, and using it as a basic unit. That means the height of the building is what I'll be comparing to every other part of the
building. Is the building wider than it is taller?
Note that the basic unit is the first measurement you establish, and you notch your pencil so that you can easily line it up again with that same basic unit. Every time you measure, you measure, you start by lining up your basic unit.
This ensures that your arm is in the same place, and you are measuring at the same scale. If your arm is even slightly off, so is your measurement. The basic unit allows you to line up your arm in the right place to accurately gauge a measurement.
Once you've determined your basic unit, you draw it on your paper first. Rarely is it the same size as what you are seeing. Most often you are enlarging what you see so the drawing of the building will appear larger than what your sight size is. So your basic unit on your subject is 1, and on your paper might be 1.5
This makes a ratio in your mind. In real life, the width of the building is twice the height 1:2
so in my sketch the ratio is 1.5:3. I try to keep it simple by sighting things the same size instead of scaling them up or down. First time you try this, keep it simple.
Once you have your basic unit down on paper, put in the line next to it, and work your way around the building like a jig-saw puzzle going line-to-line, shape-to-shape until you have the big shapes in place.
Angles may throw you. Roof lines can be unbelievable. Even street lines or shorelines on rivers. When you are sighting an angle, you can hold your pencil up at the same angle then lay it on your paper for comparison.
Or, you can hold your pencil between two fingers to make a perfect horizon line and look at the angle compared to a straight line. Its important to judge this shape in relation to that shape. Look at the angle of the windows to the roofline, that is the only way you can truly draw what you see and not what you THINK you see!
Here's a good descriptive flyer showing sight sizing:
The hardest thing about teaching adults to sight-size is getting them to draw exactly what they are looking at without interpreting it, or substituting what they think instead.
Once you have the first few shapes on the paper, you really don’t need to continue to measure. You can easily guesstimate the rest.
Here’s a few handy ways I use sighting in all my classes and art practice:
Drawing-I use sighting to measure the objects in a still life, for example, the length of the stem compared to the whole length of a wine glass. Is the stem about half the length? Is it more? I use the stem to show me how big the cup part is.
Portraits- I use sighting to measure from eye-level to chin, and on that line, I measure how far down the nose is, the lips are, etc. That line helps me to see where all the other facial features fit. I also use eye-level line to line up the eyes, and the bridge of the nose. You can drop a plumb line straight down from the corner of the eye and hit the outer edge of the nostril.
Plein Air- Sighting is crucial to being able to sketch boats in perspective. I start with a basic unit like the height of the bow, and measure how many bows long the boat is. Sighting is also crucial for placing posts on a dock, or telephone poles along a street, or even buildings.
Pastel Still Life- When painting a still life, I always measure the first item, and use it for a basic unit to compare every other shape in the still life. Hope this helps!