Thursday, January 10, 2008

Facial Aging


A basic knowledge of the physical aging processes allows you to accurately draw people of various ages. The age regression and progression techniques, discussed in this heavily illustrated article, can be invaluable for accurately portraying or modifying the ages of portrait subjects
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Serene Scene



Sketching is an action word, and you can only learn this skill by actually sketching. To give you a feel for the sketching process, numerous illustrations and simple text take you step-by -step through the process of rendering a sketch from one of my sketches (much easier than working from an actual scene).
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Hatching Value Scales



When you can render sets of hatching lines well, you discover a very fast and simple way to achieve realistic shading in your drawings. Many different styles of hatching sets can be rendered, from lines that are very noticeable, to lines drawn so closely together that they look like a solid tone.
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shading techniques


Cartoons are always fun to draw, and a lighthearted way to strengthen your drawing skills. My sketch of this mischievous looking toddler incorporates both crosshatching and hatching shading techniques
for mor information:

Slide rule


This is not a drawing tool per se, but was used by educated people for calculations. The analogue calculator is based on the logarithms, discovered (or developed) by Leibnitz, Newton and Napir 1). This principle reduces multiplication and division to addition and substraction. Potenzation and roots are reduced to multiplication and division. But also special scales for trigonometric calculations etc. were in use. The typical slide rule of an engineer had 25 scales and was 25cm long. this allowed an accuracy of 3 - 4 digits.
The sliding window shows the square of 4 (scale D) to be 16 (scale A). The tong shows the multiplication of 1.26 by 3.17 (C) = 4 (D).

Protractor


Various forms are still in use at school. The most used one provides 180°. I still have one with 400g for the full circle (and I also have trigonometric tables for these 'neugrad' or 'new gradation' which allows more easy mathematical handling of arcs).
For military use 'artillery' versions with 6400 units for the full circle were available (at least in Switzerland).

Camera lucida


You might know the camera obscura, which works only for very luminous situations. Camera lucida (light chamber) was developed by W. H. Wollaston in 1807 to draw landscapes etc. with ease.
The main component is a 4-sided glass prism. From the oject G the light is seen by the eye A in Z, where the pencil can be used to draw the object.
When the instrument is built with mirrors rather than a prism it is called mirror lucida.

Pantograph



For enlarging and reducing drawings this tool was at least in use by amateurs. Heavy duty models are still in use for engraving and contour milling.
Another form of this tool was called Storchenschnabel in German.

Ellipse compasses



Before you just could drag your mouse to get an ellipsis of any size both templates and special mechanical devices were used. The two devices depicted use different methods of drawing an ellipse.
The method using a thread is at least still used by gardeners. Using a sharp pencil, thin pins and a thin thread you can get quite a good precision by this method first described at least by Descartes (1596 - 1650):
Based on the desired long and short axes you can construct the positions of the focal points where the pins are inserted
f = sqrt (a2 - b2)
The length of the thread is
2(a+ f)

Drawing large circles


But how to draw circles, if the center can not be reached? I have only a scetch of such an instrument. There were other types available with greater accuracy, but more elaborate.
b = r - sqrt(r2 - a2) For a given radius angle alpha is constant. Because a is an instrument constant, there were tables to get b from the desired radius

Proportional compasses



Proportional compasses are used to divide distances or to 'convert' them according to a scale. A specialized device for the relation of the golden rectangle may be still in use by sculpturers and other artists. The rightmost image depicts an instrument to divide a distance into up to 10 equal parts.

Compasses



Various types of compasses and drawing pens were combined in a box of drawing instruments. The compass in this set could draw circles up to 25 cm in diameter by means of an elongation rod. To draw very small circles a drop compass and a bowcompass is included, sometimes also a dividing compass with two pins.
For larger circles the needle and pencil are arranged on sliders on a rod, which might also be eleongated. I remember that once we needed a radius of 4m. Kneeling on the floor we just used an ordinary wooden rod of that length.

French curves



A common set of curves is the Burmester set displayed here. The first item is very handy for ellipses, the second very often fitts large parts of hyperbolas and the third (largest) item is used most for parabolas.
During my time as a mechanical engineer I also used a very special courving tool: some sort of plastic snake with lead spine, about 40 cm long. This could be bent to the desired shape.
In ship building where drawings frequently were to the scale (or at least as large as rooms), another form of curving tools were in use: in German it was called straklatte. This is a long straight slat of wood or other bendable material. It was pinned down along few points shaping the curve

Template



Not only children like templates. Making illustrations on paper very often is faster than any computer based method... A standard catalogue for templates as of 1997 lists hexagons, ellipses, electrical and chemical signs etc. But writing with templates is definetely out of business.

Scale



Since various drawing scales were needed, the tool combined 6 scales, for example, 1:200, 1:50 etc. Also very strange scales for rural maps could be found: 1:1440 and 1:2880 (at least in Austria).

Ruler



For working on the desk a ruler is still a handy tool. Most time it is combined with a 1:1 scale with tic marks at every mm. For typographic purpose also rulers with pica, points etc. are still in use.
Convenient tools on the desk are parallel moving rulers. One type has (rubber coated) rollers to guide the movement. Another type connects two parallel half-rulers with two legs forming a parallelogram with the ruler.The type with the rollers often is combined with a mechanism to slip the ruler step be step for hatsching.
A more elaborate example is pictured hereafter. This is a multipurpose tool especially for students... Even math formulas and trigonometric tables are available. With the various holes on the long edge a compass can be simulated.

Square and T-square



Amateurs and students most time are confined to simple forms of a drawing board with a t-square to draw horizontal lines (the board was not square enough to allow for verticals also). Angles in steps of 15 degrees require 2 squares with 90-45-45 degrees and 90-60-30 degrees.
For the desktop A2 and A3 sized drawing tablets became available with a combination of t-square and protractor. I still have an A3 sized in use.

Drawing board



The most common drawing board for engineers and also for illustrators used a parallelograms to keep the rulers parallel to itself. The detail picture shows the 'head' of the machine: The rulers could be exchanged according to the desired scale; they could also be rotated in 15 degree steps or fixed at an arbitrary angle.
For wide drawing boards (especially used in the ship industy) the parallelogram mechanism was replaced by a horizontal rail on top with a 't-square' on roller barings holding the drawing head.

Drawing pen



Early drawing pens were made similar to forceps, with a screw to adjust the distance of the two legs which held the indian ink. I remember the time when the two legs even had to be smoothed with a honing stone to undo the waering from the very harsh paper. For my map drawing I also had a double pen (for streets) and a free wheeling pen for altitude curves (isohypses).
The pen at this drawing fountain pen could easily be exchanged for writing with types for narrow and wide lines
This was my set of pens for a number of years...