VL-IV some of my favorite things

[Glenn Scheper]

> p155 "the caustics of sunlight"  --- somebody, please, tell me what it means, but I already like it

I'd'a guessed bleaching, but check out optics:
(google define:caustic)

Definitions of caustic on the Web:

acerb: harsh or corrosive in tone; "an acerbic tone piercing otherwise flowery prose"; "a barrage of acid comments"; "her acrid remarks make her ...
any chemical substance that burns or destroys living tissue 
of a substance, especially a strong acid; capable of destroying or eating away by chemical action 
wordnet.princeton.edu/perl/webwn

A corrosive substance is one that will destroy or irreversibly damage another substance with which it comes in contact. ...
en.wikipedia.org/wiki/Caustic_(substance)

In optics, a caustic is the envelope of light rays reflected or refracted by a curved surface or object, or the projection of that envelope of rays on another surface. ...
en.wikipedia.org/wiki/Caustic_(optics)

Caustic is an American industrial band based out of Madison, WI, created in 2002 by DJ Matt Fanale (AKA Eurotic), who is the sole consistent member. The band's live lineup varies quite a bit, largely depending on the location of the show. ...
en.wikipedia.org/wiki/Caustic_(band)

caustically - in a caustic vitriolic manner; "he addressed her caustically" 
wordnet.princeton.edu/perl/webwn

causticness - The state or quality of being caustic
en.wiktionary.org/wiki/causticness

(1) Burning or corrosive. (2) A hydroxide of a light metal, such as sodium hydroxide or potassium hydroxide.
www.corrosionsource.com/handbook/glossary/c_glos.htm

Any strong alkaline material which has a corrosive or aggressive affect on living tissue.
www.cleansource.com/terminology/Terminology_IndustrialCare.asp

Corrosive; able to eat away or destroy by chemical action.
www.factmonster.com/chemistry/glossary/c.html

capable of burning, corroding, or destroying living tissue
www.eco-tec-inc.com/glossary.html

the characteristic sinuous, curved, shiny light rays seen on underwater surfaces, caused by refraction through the rippled top surface of water
www.landscapemodeling.org/html/glossary_of_terms/glossary.htm

harsh, especially in language; corrosive
www.gradesaver.com/classicnotes/titles/astrophil/terms.html

A detrimental coffee taste sensation characterized by burning, sour sensation on the posterior sides of the tongue. Caused by alkaloids increasing the sourness of the acids in combination with a high percentage of salts.
www.freakybean.com/coffee101_sub.php

A indirect illuminated light patterns. This sort light patterns are formed when light rays reflected from or transmitted through specular surfaces strikes a diffuse surface. This phenomena can be found at underwater scenes.
www.awingsoft.com/Manual/Glossary.htm

The active ingredient in an alkaline bath, generally with a pHhigher than 10, which removes aluminum from used extrusion dies by etching. The primary ingredient, caustic Soda, dissolves the aluminum alloy by chemical reactions with no affect on the steel die.
www.futuraind.com/glossary.htm

An herb or substance that contains acidic material that has an escharotic or corrosive action capable of burning or eating away living tissues. (Syn: acrid, corrosive, cauterant, escharotic)
www.motherherbs.com/herb-glossary.html

Any substance that releases hydroxide ions when dissolved in water.
www.terracontanks.com/nav/cm.aspx

Strong base (alkaline) substance which irritates the skin. Corrosive. When the term is used alone it usually refers to caustic soda (sodium hydroxide), which is used in manufacturing hard soap. It also refers to caustic potash (potassium hydroxide), which is used in manufacturing soft soap.
www.baraboosysco.com/chemical/glossary_of_terms.htm

Having the properties of a base, a pH greater than 7. Usually used as an adjective, ie "alkaline soil". See Acid, Base,pH
www.rrmsc.com/resources/glossary.htm

The caustics are referred to as the refraction pattern formed by highly transparent objects such as a glass of fluids which have a certain degree ...
download.blender.org/documentation/htmlI/ch28s04.html

caustics - in optics is a bundle of light rays. For example a caustic effect may be seen when light refracts or reflects through some refractive or ...
en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Terminology

caustics - Corrosive materials, such as caustic sodas, used in the manufacture of chemicals.
www.dscrt.com/glossary.asp

caustics - The concentrated light reflections caused by refraction through a transparent surface. Channel : An image component that contains the pixel ...
gravitystation.net/def1.htm

caustics - Light patterns formed on other objects by the reflection or transmission of light striking a reflective or refractive surface
www.kxcad.net/catia/B17doc/English/online/psoug_C2/psouggl.htm