To UV or not to UV....
To UV or not to UV....
- Subject: To UV or not to UV....
- From: Jim Rich <email@hidden>
- Date: Tue, 11 Dec 2001 15:51:47 -0500
Last week I was commenting about the Eye One and a potential UV problem.
These comments are a follow up on what I have determined so far. And it is
not really anything so earth shaking.
The problem first looked like the GretagMacbeth Eye One was the source of an
UV problem because the instruments specifications does not include a UV
filter like other spectros. From my tests of creating profiles from on
various types of papers I found that yes there is a slight problem with UV
not being filtered out of papers that contain a high degree of brighteners.
I used a DTP 41 with a UV filter in these tests. The printer I used in my
lab was an Epson 5500 I consider this printer to offer the similar behavior
to an Epson 10,000. And from my tests the 5500 does have have very similar
behavior to the 10,000 for this series of tests I performed.
I even went as far as buying an anti UV coating(at the recommendation of
Steve Upton) to spray my printer patches. This seemed to help some but it
produced a weird (kind of clipped) color gamut for the printer profile.
The conclusion I have come to in regard to the UV problem with the Eye One
is that, yes there is a slight problem, but it IHMO it is insignificant and
there are other problems that are more significant and cause more color
variation issues.
Technically speaking, the problems that my client is complaining about
involves two things. The first is the Espon when it is used with the RGB
driver and improper lighting.
What I mean by the Espon printer with the RGB driver is that when I printed
an RGB gray scale from Photoshop, each of these printers introduced a color
banding into the printed grayscale that is very easy to see. I did this with
the printers settings set to their off position and printed an image using
same as source option in Photoshop and then printed an image with a printer
profile. The problem is easily seen either way the image is printed. If you
want to remove the color casts you have to edit the profile. This can be
tricky even for experienced color people because you have to change a few
levels at least two colors in the 3/4 in one direction and then two more
colors a few levels in the midtone.in another direction.
It appears that another solution to fix the color banding in the printed
gray scale seemed simple to me, linearize the printer. So I pulled out one
of my RIPs and used its linearization to verify this solution. It did. When
I printed my test images (including an RGB gray scale ) through the Rip with
a linearization the color banding went away on the Epson 5500 as I am sure
it will at my clients site who owns the Epson 10,000 as soon as they buy a
good Rip. And it sound like they will in January when a Mac version of the
Rip they want is released.
The second part of the problem is my clients lack of understanding that they
need to use a common place (like a D50 light booth) to view Epson prints and
color reproductions in general. By not using a standard viewing area their
color decisions were inconsistent and making every one crazy.
Jim Rich