RE: Convert UV-excluded to UV-included
RE: Convert UV-excluded to UV-included
- Subject: RE: Convert UV-excluded to UV-included
- From: Roger <email@hidden>
- Date: Tue, 22 Dec 2009 07:59:00 -0500
Chris,
I think you should pursue your thoughts on this whole UV business.
For myself, I have determined that all substrates for which we would want to
apply some kind of UV correction don't necessarily have the same amount "UV
content", meaning that, when submitted to a UV-rich light source like that
of a fluorescent tube, will not "react" the same, however this is
characterized.
If there was a way, IMO, to establish a-priori the amount of optical
brighteners in a given substrate, in absolute terms, on some kind of
industry standard scale, then, perhaps, this could be matched with a graded
system of optical correction. Perhaps. Because, you see, another important
consideration in this UV correction scheme is the "UV content" from the
light sources under *which* the substrate will be viewed: a fixed correction
maybe adequate for one kind of light source while not enough for another, or
too much.
In the end, in my humble experience, the easiest fix for this is to avoid
substrate with optical brighteners altogether. How reasonable is that?
Depends on the application. But there are a fair number of inkjet substrates
out there (if that's what you're after), at reasonable prices, that will
satisfy the needs of many applications. It does not mean that such a
substrate may be completely devoid of optical defects. There could still be
other lingering issues with the measuring instrument geometry or other
characteristics of the inks or media that concur to its relative color
inconstancy (I used to believe naively that there wouldn't) but it's a hell
of a far cry from optically-brightened media.
That's why I say any instrument that does not have a UV-cut filter is fine
for *all* color work.
It seems everyone on this list's mileage vary but that's where I'm at today.
Roger
> Let me add to what I was thinking. I realize that the UV information is
> missing from measurements taken with a UV-cut device. You wouldn't be
> able
> to simply say a measured value of X should equal Y. What if you could,
> though, plug in a variable representing the OBA in the paper?
>
> This value could be a range, say 0 to 10. Paper with no OBAs would be 0
> while paper with the maximum amount of OBAs would be a 10. As long as
> you
> knew what the value was for a particular paper you should be able to
> derive
> a fairly accurate simulation of a non-filtered measurement. You would
> also
> have to know, and the equation would have to account for, the level of
> UV
> light in the light source representing the simulated measurement. Of
> course
> you would have to have a standardized way of specifying the OBA value
> for
> any given paper. Assuming such an OBA rating standard existed, would
> this be
> feasible?
>
> To my original question of does such an equation exist, I think the
> answer
> is no. So my next question then is could it be done?
_______________________________________________
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