--- ray/src/cv/mgflib/spec.txt	1994/07/22 09:58:52	1.5
+++ ray/src/cv/mgflib/spec.txt	1995/03/07 14:53:31	1.7
@@ -27,9 +27,8 @@ current transform and the current object name.
 Each entity is given by a short keyword, followed by space- or tab-
 delimited arguments on a single line.  A single entity may be extended
 over multiple lines using a backslash ('\') character right before the
-end of line, though no extended line may exceed 512 characters in total
-length.  (Given the current set of entities, even approaching 80
-characters would be highly unusual.)
+end of line, though no extended line may exceed 4096 characters in total
+length.
 
 Entities and Contexts
 =====================
@@ -84,6 +83,7 @@ n	dx dy dz		set surface normal for current vertex
 c	[id [= [template]]]	get/set color context
 cxy	x y			set CIE (x,y) chromaticity for current color
 cspec	l_min l_max v1 v2 ..	set relative spectrum for current color
+cct	temperature		set spectrum based on black body temperature
 cmix	w1 c1 w2 c2 ..		mix named colors to make current color
 m	[id [= [template]]]	get/set material context
 sides	{1|2}			set number of sides for current material
@@ -210,18 +210,22 @@ saturation.  Intensity, such as reflectance or emittan
 included in the other material parameters.  All colors are absolute,
 e.g. spectral reflectance or transmittance under uniform white light.
 
-A CIE xy chromaticity pair is the most basic color specification.
-A full spectrum is the most general specification, and the starting
-(i.e. minimum) and ending (i.e. maximum) wavelengths are given along
-with a set of evenly spaced values.  Wavelengths are given in nanometers,
-and must be within the range of 380-780.  The spectral values themselves
-are located starting at the first wavelength and proceeding at even
-increments to the ending wavelength.  The values in between will be
-interpolated as necessary, so there must be at least two specified points.
-The color mixing entity is intended not only for the mixing of named
-colors, but also for color specifications  using an arbitrary set
-of basis functions.  The actual totals for spectral and mixing
-coefficients is irrelevant, since the results will be normalized.
+A CIE xy chromaticity pair is the most basic color specification.  A
+full spectrum is the most general specification, and the starting (i.e.
+minimum) and ending (i.e. maximum) wavelengths are given along with a
+set of evenly spaced values.  Wavelengths are given in nanometers, and
+should be within the range of 380-780.  The spectral values themselves,
+which can be thought of as relative power density per nanometer, start
+at the first wavelength and proceed at even increments to the last
+wavelength.  The values in between will be interpolated as necessary,
+so there must be at least two specified points.  The color temperature
+entity corresponds to the spectrum of a black body at the specified
+temperature (in degrees Kelvin).  The color mixing entity is intended
+not only for the mixing of named colors, but also for color
+specifications  using an arbitrary set of basis functions.  The mixing
+coefficients are in effect relative luminances for each color
+"primary."  The actual total of the mixing coefficients or spectral
+values is irrelevant, since the results will always be normalized.
 
 Diffuse emittance is always given in SI units of lumens/meter^2.  Note that
 this is emittance, not exitance, and does not include light reflected or