## Saturday, 15 June 2013

### How to draw a line

One of the key Foundation course sessions in relation to perceptual drawing was drawing a straight line. I have alluded to this several times, so I suppose I ought to explain in detail how this was done.
Students would first of all have to position themselves in relation to a straight. This was most commonly a set of studio floorboards or if space was restricted, the edge of a table. The relationship between the student and the straight had to be initially at right angles and there had to be enough length to the straight for students to have to shift their gaze left and right in order to be able to look at the entire length of the line. Typically this meant that the angle of vision between a student and the straight had to be wider than 60%. This could mean a student sitting 10 feet away from the centre of a floorboard running at right angles to their eyes, if asked to draw a floorboard 30 feet long; or a student being 2 feet away from a table’s edge, is asked to draw an edge 6 feet long. In plan view the situation is like a T with an extremely long top bar in relation to the vertical. The floorboard situation meant that a student’s eyes were automatically situated above the plane of the line, however in the case of a table edge it was important to have a student standing at an easel rather than sitting, as there could possibly be a situation whereby the student was looking directly at a table edge at the same height as his or her eyes. Although this would not make the drawing impossible, it would make it much harder.
Once situated properly the student is asked to check that they are at a right angle to the floorboard or table edge. They can then mark this central point off with a piece of chalk, using a T square if possible to check the accuracy. Using a plumb line they then recheck this drawn angle. They are then asked to look to the left or right and carefully measure the angle made by the conjunction of their plumb line and the straight at the point furthest away from them. If working in pairs, they can then get the other person in the pair to chalk in the new angle in relation to the straight. This new chalkline should sit exactly on the vertical of the student’s plumbline, the angle it makes with the floorboard can then be measured. If the student has turned to the right to make this first measured angle, what they should find is that it is no longer a rightangle, the angle to the left of the chalk line will be less than 90% and that to the right of course more than 90%.
No actual drawing has been done yet and time is spent getting students used to the amount of head turn that is needed to get into a position to accurately measure the difference between the central point on the straight and points to the left and right. Finally before starting out drawing, students are asked to measure the difference in length between them (where their eyes are) and the floorboard's central point and its far points. In some cases, especially if we were doing this in the very large studio the distance between a student and the closest and furthest points on a floorboard could be considerable, but even if we were restricted to table edges, it was expected you could get at least double the distance.
Students might be working on a donkey or at an easel, they would usually have an A1 drawing board and A1 white cartridge of a medium weight to work on. Once set up they would be asked to make a vertical line in pencil that was to be used as their key measuring line. This was to be placed centrally within a sheet of paper of landscape format. They would then check their position. In order to be able to see the line the easel or donkey had to be positioned slightly to the left or right of the situation to be drawn, this of course meant that even to check the central vertical, the student would have to move their head between the moment of measurement and the moment of transfer onto the paper. They would therefore spend some time getting comfortable with this. They would check the vertical, move back to the drawing board and when ready make a mark at right angles to the first vertical that would at the point of crossing represent their perceptual understanding of where the central point of the perceived straight was.
The next step was more difficult to understand. Students would be asked to chose another point further along the line, check the angle made between their plumbline and the floorboard or table edge, then attempt to draw this angle. They would also using a vertical, measure how far away this point was and compare this distance to the first point. If they were using a pencil to measure with, they would check their pencil was vertical and slide their thumb up and down taking sight-sized measurements. They would also hold this pencil horizontally checking that it was lying exactly on the horizontal at the central point of the line and carefully rotate their body, holding the pencil without wavering, until the other second angle came into view. This angle would if the hand was steady come into view slightly above the pencil. This distance could then be measured and checked against the measurements already taken. Once movement to the left or right were measured a few times and checked, and this distance slightly above the horizontal again checked, students could make a second set of marks on their paper. One would be a vertical that would represent the verticality of the measuring device, (pencil, plumb-line etc) the other would be a short line at an angle that corresponded to the one observed. Again if working in pairs students could ask their partner to chalk a vertical through the straight at the point of measurement. Some students would use a chalk line running from their drawing position so that they eventually ended up with a floor plan that looked like a fan of lines coming from the centre of a giant protractor, the radiating lines meeting on a straight rather than at the edge of a circle.
As drawings evolved, the floor-plans evolved. Students would get up from their easels, measure distances and angles, chalk these in and return to the easels checking over and over again that they were right. As each measurement re-check was made, adjustments to the drawing would be made by rubbing out marks and replacing them with new ones.
Eventually a gentle curve would be implied by the relationship that was being built up by the marks. The bottom of the curve being in the centre of a line that was slowly rising to both the left and right. The more measurements made the more an implied line came into view, each measurement point being stabilized by a short vertical which was crossed by a gradually changing angle as the measurements moved away from the central point. Gradually other factors could be brought into play. If a measurement point was close to the student perhaps this could be intimated by a slight increase in mark weight. Small subtle adjustments could be made to more finely ‘realise’ the situation, until the perceived line ‘vibrated’ with hundreds of adjusted and erased marks, it’s image a compacted ‘memory’ of adjustment and perceptual struggle.
These drawings could take all day, sometimes longer, the point being that to really grasp the problem and practice the skills of measurement required if you were to establish the fact that you were at the centre of a sphere of perception, you needed a lot of practice. In particular carrying the information between the moment of measurement and the moment of recording was a time for much subjectivity; lots of guesses tending to be made as to what students thought these lines should look like. In addition some students were often tempted to ‘draw the line in’ and they had to be held back until their eyes did that for them.
At the end of this session it was to be hoped a lot of lessons had being learnt, the simplest of which were to do with taking visual measurements with a moving thumb and a vertical, the more complex being to be with how difficult it is to record any complex of visual perceptions.

One further point of course being that words complicate matters and that most of what we were doing was done by demonstration.