Re: Paper Question
Re: Paper Question
- Subject: Re: Paper Question
- From: Terence Wyse <email@hidden>
- Date: Tue, 09 Sep 2014 11:52:09 -0500
If you subscribe to the newer CRPC (Characterized Reference Printing Condition) references, based on “substrate-relative colorimetry”, substrate Lab is not all the critical…..but like Roger said, the new GRACoL2013 “CRPC” profile has white point closer to real-world conditions, i.e. papers with OBAs.
Terry
On Sep 9, 2014, at 11:45 AM, Roger Breton <email@hidden> wrote:
> I think the question of "acceptable" tolerance is up for grabs.
> I personally (shame on me if this information exists already!) have not seen a cast in stone criteria for this?
>
> In my humble experience, on almost all printing papers I've seen, a* is always very close to 0.00. So you can ignore it.
> L* should be the deciding factor whether to categorize a substrate relative to SWOP3 or GRACoL as far as coated papers are concerned.
>
> The b* component is the killer.
>
> I think the last specs from IDEAlliance, GRACoL2013, have jacked up the b* component to -4.00, to account for the fact that many grades are not as neutral as we would like.
>
> So to "qualify" a grade as being "GRACoL2006", is Plus or Minus 2 "acceptable"?
> I'll let the other speak for fear of putting my foot in my mouth publically, even though I have my idea ;-)
>
> Best / Roger
>
> -----Original Message-----
> From: colorsync-users-bounces+graxx=email@hidden [mailto:colorsync-users-bounces+graxx=email@hidden] On Behalf Of Mike Stewart
> Sent: 9 septembre 2014 12:20
> To: email@hidden
> Subject: Paper Question
>
> Hello: I will try and simplify this. Let's say I have 20 different press sheet papers and I am measuring the *L*a*b values of the paper in M0 mode to see if they fit under Gracol2006, SWOP3c2, etc. Is there a rule of thumb as to the allowed variance; not a DeltaE variance; but a plus/minus variance?
>
> One paper may be L: 95, a: 0, b: -2 (Gracol2006)
> another may be L: 92 a: 1, b: -1 (could be SWOP3v2 or Gracol2006)
>
> So; if Gracol is L: 95, a: -0.03, b: -1.95 can I look at something as simple as
> L: 95 +/- 2, a: -0.03 +/1, b: --1.95 +/- 1
>
> Thanks - Mike Stewart
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