Jacqueline du Pré Sans Makeup & the Inverse Square Law
Any photographer worth his salt (on this subject I am extremely salty) knows about the inverse square law in relation to light. What is most interesting about this law is that it is the same for gravity.
The inverse-square law, in physics, is any physical law stating that a specified physical quantity or intensity is inversely proportional to the square of the distance from the source of that physical quantity. The fundamental cause for this can be understood as geometric dilution corresponding to point-source radiation into three-dimensional space.
Mathematically notated (see ∝):
intensity ∝ 1 distance 2 {\displaystyle {\text{intensity}}\ \propto \ {\frac {1}{{\text{distance}}^{2}}}\,}
It can also be mathematically expressed as:
intensity 1 intensity 2 = distance 2 2 distance 1 2 {\displaystyle {\frac {{\text{intensity}}_{1}}{{\text{intensity}}_{2}}}={\frac {{\text{distance}}_{2}^{2}}{{\text{distance}}_{1}^{2}}}}
or as the formulation of a constant quantity:
intensity 1 × distance 1 2 = intensity 2 × distance 2 2 {\displaystyle {\text{intensity}}_{1}\times {\text{distance}}_{1}^{2}={\text{intensity}}_{2}\times {\text{distance}}_{2}^{2}}
The divergence of a vector field which is the resultant of radial inverse-square law fields with respect to one or more sources is everywhere proportional to the strength of the local sources, and hence zero outside sources. Newton’s law of universal gravitation follows an inverse-square law, as do the effects of electric, magnetic, light, sound, and radiation phenomena.
In photography what this means is that if you keep your light in one place and move your subject to twice the distance you will need four times the intensity of light in order for it to match that of your subject one half of the distance. Because the eye can play tricks, and particularly in a studio, I have always depended on a very good flash meter.
I have now been scanning the plants and flowers (mostly roses) from my garden. I suspend a slim and dark bamboo pole over the scanner and suspend my plants so that they almost touch the glass of my Epson Perfection V700 Photo Scanner. If you place the flowers (particularly roses) on the glass the petals are squashed. Worse still is a white rose. That part of a petal close to the glass or touching it will overexpose (classic case of the inverse square law).
A few days ago I scanned the first rose of the season in my garden. It was Rosa ‘Jacqueline du Pré”. Today May 10, 2018 I put the rose (another bloom) on the glass and allowed it to collapse. I am quite pleased with the results.
It sort of represents Jacqueline without and makeup. There is not perfection here. It is beauty as is even if you can discern black spot on the lower leaf.
