User-agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.4) Gecko/20030624 Netscape/7.1
Chris McFarling wrote:
So it's possible for two vendors to submit a proof to a customer with each
claiming that their proof is SWOP compliant, although each of the proofs may
be significantly different visually?
"Significantly" is the interesting term here. I am sure that the SWOP
people would not agree that there is a "significant" difference. I
think they would say that it is a "close" match.
Now the question is...If two colors are "significantly" different what
is that equal to in Delta E? What Delta E is equal to "close"? Should
the tolerance be less for colors near the gray axis than more fully
Until the industry agrees on standard international units of color
measurement and methods of tolerancing we will continue to talk in
circles. If we are going to have standards they must be based on
In experiments it has been shown that viewer metamerism can account for
differences as high as Delta E of 5. This means that you can have two
non-color blind people that are viewing side by side color patches under
D50 light and choose adjustments for a match that differ by as much as
Delta E of 5.
I would suggest that you measure 50 sheets at the beginning of a press
run and then 50 in the middle and 50 at the end. Now see what the
variation is with your run. Next measure a standard target placed top
of your press sheet and then another at the end of the sheet. This
might change your expectations about how tight the tolerances should
be. Of course we would have higher standards for proof consistancy
than on press.
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden