This whole issue of "realistic" is somewhat unrealistic. Photo-realism or
whatever one calls it is as much an artificial convention as any other means of
artistic expression. But this gets us into a relativistic riddle about light and
perception and pictures and how the brain processes visual sensations and how we
see things that's well beyond this issue. Even when we assume that we want to
make a picture that "looks just like" say a sunset over a lake we are in effect
not reproducing how we would see such a sunset but how we think we see it. We
are making a picture of it.

Lecture follow so you can skip to step w: The history of visual representation
has only recently adopted the notion that we see in pictures. As if we could see
ourselves seeing. Like a little observer standing behind our retina looking out
as if viewing a motion picture or a computer screen. As the state of perception
theory stands now the model of a "realistic" picture on the retina is being
replaced by the idea of the retina as just a converter box, while it's the
visual cortex that post-processes those visual sensations in ways that alter
their purely physical or mathematical input. Note, for example the banding on
the gradient example. That scalloping effect that enhances edge, is not in the
physical input but in the way the brain processes patterns of light and one
could say distorts the purely, as Steve Jobs would say, "retinal display". There
are several artificial notions in POV that do not exist in the real perceptual
world. Like ambient. Nothing has color without light unless it's a source of
light. It's just adjust control Sorry for the lecture here but I've been
fascinated with how we see for a long time. How the "human machine" sees is
truly a mystery.

With regard the new gamma model that's being applied to POV, two points: POV is
first a description language not like Photoshop were you just slide sliders back
and forth until things look right. There is nothing wrong and even wonderful
about this approach as long as you have immediate visual feedback. In POV you do
not. It's like taking photographs in the pre-digital age. You use an educated
guess to adjust aperture and f-stop or whatever and only in the darkroom do you
finally see what develops. Add to this add the fact that rendering and parsing
do not take a few minutes but sometimes days or even weeks. So as a description
language you have to learn techniques to anticipate what you want to come out or
at least to get something that after a week is not going to look like crap. So
when you tell the program draw a straight line from point A to point B, you
don't want to see at the end of the process something that not only looks like a
curve but is a curve. So to get to the point of the gradient example. It tells
POV that we want a linear succession values over a certain distance what it does
is give an exponential curve. That's fine but not what I intended and, if you
can't depend on 1 plus 1 plus 1 etc coming out a 3 or 4 or what ever, how do you
use a language that's going to be retranslated to mean something totally
different than what you expected it to say.

In 3.6 the evenly ramped gradient looked right. The values reported in Photoshop
or whatever said yes indeed 1 plus 1 is two. I've used POV in every possible
way, on Macs and PCs, to make images that looked fine in IE and FireFox or
Chrome or in print, and have in fact never encountered problems as serious as
this major revision seems to solve. I would like to see a concrete scene we
could render in both versions where it is demonstrated the need for the change.
But now there seems no way of predicting but more trial and error. I've used POV
for a long time because I love it like an addict, it's surprises and limitless
control. Now everything feels even more unpredictable and confusing.

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