--- ray/doc/notes/ReleaseNotes	2022/10/19 21:25:20	1.422
+++ ray/doc/notes/ReleaseNotes	2023/11/27 22:04:45	1.433
@@ -2582,3 +2582,57 @@ This addition was suggested by Peter Apian-Bennewitz a
 way to determine which version of Radiance is installed and what
 it supports, and is timely as we begin our refactoring of the
 rendering code.  There are no current plans to add this to rvu.
+
+Added falsecolor -odim, -orct, and -c0 options to overlay grid of
+values on image.  This was requested by Rob Shakespeare.
+
+Added -i* and -o* options in rhcopy for reading rays from the
+standard input and writing rays from holodeck to standard output.
+This will hopefully be useful in combining rholo with rcontrib.
+
+Added further checking for coincident (overlapping) flat surfaces,
+preferring front sides to back sides in the ray intersection
+calculation.  This only applies to rings and faces, as the other
+surface types would have required additional calculations to
+make them work.  Material transparency is still the primary
+consideration, now followed by ray hit side, followed by
+modifier definition order in the input.
+
+Increased octree and object limits to allow scenes with billions
+of primitives.
+
+Made reciprocity averaging default to "off" in bsdf2ttree, as it seems
+to create more problems than it solves.
+
+====================
+Version 6.0
+
+Extensive changes to enable spectral rendering, which defaults to "off"
+to maintain backwards-compatibility with previous versions, with the
+exception of the ambient file format, which is changed.  The MAXCSAMP
+macro, which defaults to 24, sets the maximum number of spectral samples.
+The actual number of samples is set by the "-cs" option, which defaults
+to 3 for rpict, rtrace, and rcontrib.  The latter two programs support
+straight spectral output, but rpict is initially restricted to
+tristimulus output pictures.  New pattern primitives "spectrum",
+"specfile", and "specfunc" have been added as a means to specify
+spectral reflectance, emittance, etc. to materials that still have
+only 3 color channels.  Those RGB channels will still affect the
+spectrum if used.  Unfortunately photon-mapping is currently broken when
+spectral sampling is enabled, but we will fix this as soon as possible.
+Calculation overhead appears to be approximately 10-15% for RGB
+renderings compared to version 5.4a.
+
+Added spectral rendering to rvu as well, and made -cs and -cw
+options standard across the rendering library.  I also brought
+mkillum, ranimove, rsensor, and mksource into the fold.  These
+tools were broken in the initial release.  (Hopefully, they are
+working now, but none have been tested as yet.)
+There was also an indexing bug in the spectral->RGB conversions
+that made reds into blues and vice versa, which has been fixed.
+
+Added i/o for spectral pictures to rmtxop, the first program that can
+ingest them.  (Only rtrace, rcontrib, and rfluxmtx can render them.)
+New symbolic rmtxop -c options, such as RGB, XYZ, S (for scotopic)
+and M (for melanopic) make color conversions simpler.
+Also added spectral picture support to rcrop and radcompare.