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multimedia breakout notes (20 june 2001/GL f2f)

From: gregory j. rosmaita <oedipus@hicom.net>
Date: Thu, 19 Jul 2001 13:58:15 -0400
To: <w3c-wai-gl@w3.org>

PRESENT [compiled from memory apologies to anyone not
  Charles McCathieNevile, CMN (discussion leader)
  Lisa Seeman, LS
  Antti Raike, AR1
  Adam Reed, AR2
  Jan Richards, JR
  Gregory J. Rosmaita, GJR
    Maya DeWitt, ASL translator
    Caroline O'Leary, ASL translator


LS: what would be very useful would be to specify colors
that can be used to provide maximum contrast and minimize
perceptual black holes -- 2 quite different color
disabilities; leave the color to the rendering; what might
be nice to do would be to use namespacing

JR: that's when color is important

LS: that's when color is important

JR: wouldn't want to change the color of a traffic light

AR2: redundancy of position

CMN: talking about both cases -- it is worth noting that
there are 3 different types of color disabilities:
diminishing perception of blue, red-green color blindness;
grayscale vision; in the traffic light example, changing the
color is tricky, but the redundancy is by position and
brightness -- only one bright at a time

AR2: there are those that can't perceive brightness -- need
degradation scheme to go from a photo to a single line
drawing, first removing color, then scale, then anything
other than the outline -- once you get something
distinguishable at each level of degradation you've met the
degradation criteria; another criterion is the cognitive
components of vision which most people doesn't know about
agnosia, but it is quite frequent; focal cognitive
disability -- inability to identify any visually presented
information despite normal visual acuity and ability;
noticed in reference to icons, representations of realistic
things -- editing a film by showing an eraser on a piece of
paper doesn't work -- cutting is a means of editing film, so
it would work; some icons you can make sense of very easily,
but some that required complex cognitive

CMN: this is something that SVG as a technology handles very
well -- SVG Access Note contains some details about how to
do that; what do you do with these technologies?  What are
the color disabilities?  What kind of information should be
presented?  How do you draw a picture that communicates?
Use of color is very useful for a lot of people -- what do
we want to keep in our representations of visual objects;
icons discussion seemed to lead to a preference that led to
color coding -- each a different color

JR: process color rather than picture which can be much much

CMN: pointers?

JR: perceptual research -- they have numbers, which make for
good minima

CMN: color disability information -- references scattered
through the list need to be collated

JR: motion agnosia -- can't identify motion; facial agnosia
-- can't recognize faces; reverse agnosia -- mirror vision

CMN: end up with a list of things you can't rely on, but we
also need a list of things you can use

AR2: an outline drawing of a face with a specific expression
can be perceived faster than a picture of a face

CMN: for things that are more abstract than Charles, where a
photo is useful, outlines are faster to process?

AR2: yes

JR: no, color

AR2: yes, color is faster -- color, light/dark, outline

// ACTION JR: find reference and send to list //

CMN: associating motion -- is that generally a good thing,
given the proviso you must be able to turn it off

AR2: people are too good with motion -- it blocks perception
of everything else

CMN: association of sound

JR: will reinforce a visual thing -- having the 2 out-of-
sync can mess people up

AR2: if have things that are expected to be vertical or
horizontal, if are even a few degrees off, that screws
things up

JR: prettiness has a lot to do with symmetry -- if cut a
picture of a face in half whichever one of the 2 sides is
flipped, that will appear prettier than the original

JR: higher processing can be affected by degrees of brain

AR1: size of documents can have big impact -- long streaming
video, the alternative can be as big or bigger than the
original; subtitles are easy, but ASL or other sign language
used as subtitle takes up a lot of bandwidth;
synchronization is essential; ability to switch between
subtitles and signing

GJR: aesthetic concerns of content creators can potentially
be allayed by use of SVG which allows the user to restyle
the graphic so that it can be perceived while allowing the
author the requisite specificity as regards the designation
of colors, shapes, etc., with the added benefit that (a) the
graphical content is scaleable, so it will not distort if
enlarged or shrunk and (b) SVG has a robust title,
description, and text-flow models

CMN: right, but the underlying principle is that one must
have access to content in order to change it in order to
discover what the content is

AR2: semantics conveyed by layout can be misunderstood; when
reading from right to left, placement of iconic information
can be confusing

CMN: expressing relationships in SVG -- RDF and other
technologies allow us to express those relationships;
browser takes that relationship info and renders it
graphically, which is a useful thing for someone who can't
see original, but also because it allows you to transform it

AR1: metadata important -- can help people discover what
they are missing or what the author intended; but as GJR
pointed out several times today, writing such info is an art
Received on Thursday, 19 July 2001 13:57:15 UTC

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