Re: To UV or not to UV....
Re: To UV or not to UV....
- Subject: Re: To UV or not to UV....
- From: neil snape <email@hidden>
- Date: Wed, 12 Dec 2001 00:30:59 +0100
on 11/12/2001 21:51, Jim Rich at email@hidden wrote:
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The problem first looked like the GretagMacbeth Eye One was the source of an
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UV problem because the instruments specifications does not include a UV
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filter like other spectros. From my tests of creating profiles from on
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various types of papers I found that yes there is a slight problem with UV
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not being filtered out of papers that contain a high degree of brighteners.
Yes if you look at the numbers there is a difference. If you look at the
results there is a difference too. What most people are forgetting to look
at closely though is the impact of various profiling packages. So to say
that the profiles are very close would also be true of uv vs. non uv read
charts. Depends on how close you expect the results to be and through which
workflow.
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I used a DTP 41 with a UV filter in these tests.
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I even went as far as buying an anti UV coating(at the recommendation of
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Steve Upton) to spray my printer patches. This seemed to help some but it
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produced a weird (kind of clipped) color gamut for the printer profile.
Did it perhaps change the surface creating diffusion from the lighting
geometry?
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driver and improper lighting.
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What I mean by the Espon printer with the RGB driver is that when I printed
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an RGB gray scale from Photoshop, each of these printers introduced a color
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banding into the printed grayscale that is very easy to see. I did this with
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the printers settings set to their off position and printed an image using
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same as source option in Photoshop and then printed an image with a printer
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profile. The problem is easily seen either way the image is printed. If you
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want to remove the color casts you have to edit the profile. This can be
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tricky even for experienced color people because you have to change a few
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levels at least two colors in the 3/4 in one direction and then two more
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colors a few levels in the midtone.in another direction.
That's the stickiest part of all the profiles I've seen. How does one edit?
From the response on this list most packages that edit have more things to
think about before editing than the whole lin/profiling , profile building
together with interfaces that just don't stand up. When the interface idea
is good (like in the Kodak ColorFlow) there is still the question of intents
directions and can it does input edits , space etc, etc.
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The second part of the problem is my clients lack of understanding that they
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need to use a common place (like a D50 light booth) to view Epson prints and
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color reproductions in general. By not using a standard viewing area their
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color decisions were inconsistent and making every one crazy.
I've been walking around from room to room even upside down , on stilts,
anyway I can observing the phenomena of color variation depending on the
light. What people see in the Epson prints is also true to varying degrees
with so many other supports, printed or not. Surprised me as I had never
notice before the change in perception of the variance of colors depending
on the light properties.
Thanks for the good feedback Jim.
Neil Snape email@hidden
http://mapage.noos.fr/nsnape