Christopher Bartlett
Bartlett's Chi Ratio is a mathematical constant related to the golden ratio. He called it the chi ratio as chi (χ) follows phi (φ), the symbol for the golden ratio, in the Greek alphabet.
This meta-golden ratio chi is a pleasing mathematical number with remarkable geometric properties similar to the golden ratio. But instead of partitioning into a phi rectangle and a square, as in the golden ratio, its rectangle sub-divides into phi and chi rectangles.
The chi ratio is one of the solutions of Χ² - Χ/ϕ = 1 and corresponds to [1+√(4ϕ² + 1)]/(2ϕ); its numerical value is 1.355...
Starting with chi ratio canvas dimensions, Bartlett’s composition
achieves a reciprocal correlation between the canvas rectangle and
the proportional divisions of chi and phi ratio rectangles and
squares that structure the interior grid design.
The elements of the painting are aligned with these self-similar
areas and consequently at repeating measures from each other. This
geometrical underpinning provides the desired aesthetic coherence
that marshals all the parts into a unified organizational plan.