The laws of additivity and proportionality of colour matches, Grassmann's
laws, are the basis of all colour theory, but are not axiomatically true. The
extent of departure of human vision from Grassmann's laws has been
periodically examined. One exploration, by W. A. Thornton, found
considerable failure of transformability of primaries - a symptom of
Grassmann additivity failure. In the 14 years since Thornton's finding, several
groups have formed to replicate and understand Thornton's results and the
limitations of Grassmann's laws. CIE TC 1-56 is the latest of these. During the
ten years of this committee's existence, statistical simulations indicated that
replicate matches by the same observer (not present in Thornton's data) are
required to suppress random errors, and accordingly three laboratories
generated intra-observer matching results in three different luminance
domains. Two of the studies, respectively conducted at 300 cd*m-2 and
30 cd*m-2, confirm Grassmann additivity, but the third study shows failure of
additivity at 3 cd*m-2. In addition, Maxwell and maximum-saturation colour
matches have long been known to be inconsistent even at high luminance
levels and with intra-observer match replication to suppress noise. A practical
consequence of the failure of additivity could be problems observed in crossmedia
colour matching, although cross-media studies also have other well
known sources of imprecision when the colour-matching is asymmetric. Some
suggestions are made for a covering theory of Grassmann's laws that might
accommodate both Maxwell and maximum-saturation match data while still
maintaining consistency with high-luminance success in experiments such as
reported recently. Further investigations are indicated for a successor to TC 1-
56.
| File Size : | 1
file
, 200 KB |
| ISBN(s) : | 9783901906787 |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 20 |
| Published : | 12/01/2009 |
