It is the canon law, to which Egyptian artist were mandated to regularize dimensions and scale. A guideline for Egyptian artist to follow.
Added 10/03/09: According to the law, the human body (as depicted in their art) must be 18 units length to the hair lines and just under 19 to the top of the head. The bellybutton should be at 11 units length. This is beginning the measurement from the soles of the feet.
Basically, you take 19 equal-in-high units and you draw the hair line at number 18 and bake sure the bellybutton ends up in the 11th unit.
During this period (as stated by the previous answer), it was literally mandated for artists to follow these rules (freedom anyone?). As known to artists, a canon is the basic model or rule that characterizes a style.
A canon of proportions
proportions are used in scale factors; scale factors ARE proportions
canon
The Greek sculptor Polykleitos designed Doryphoros(Spear-Bearer),as an example of the "canon" or "rule", showing the perfectly harmonious and balanced proportions of the human body in the sculpted form, about 440 BC.
The Greeks used idealism in sculpture, representing people perfectly. That is when you see canon of proportions, and figures such as Doryphorus. This style, however, developed into realism, which is closer to an honest depiction of an individual.
In Egyptian sculpture, canon refers to the standardized proportions and rules that governed the creation of statues and reliefs. These canons were based on idealized notions of beauty and were used to create an unchanging and timeless representation of the human form. These canons included features such as the rigid frontal pose, rigidly arranged limbs, and elongated proportions.
They are other proportions.
Proportions of differing proportionality
HD video proportions are 1024x720 :)
The Canon ribbon is used as a part of Canon's machines. For example, the Canon ribbon might be used for Canon's printers and for Canon's digital cameras.
you can use scale model to measure proportions
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