Re: RCC 4.0
Re: RCC 4.0
- Subject: Re: RCC 4.0
- From: Joel <email@hidden>
- Date: Mon, 6 Nov 2000 09:17:14 -0600
SORRY FOR THE DOUBLE POST!
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Hi Joel,
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I just got my FJ-500 with RCC 4.0 and I find the images printed to be great.
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I also found out that if I print images using RGB and lets the RIP converts
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into it's output profile, I get a higher gamut compared to images already
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converted to their CMYK profile.
That's what we do, too.
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I'm planning to match my prints to our Press so I can use it as a proofer
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for large images since my Dysub is just A3+. During my exploration, I found
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out that I have to get the best density adjustment in the RIP to get a good
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color with less dot gain.
How are you adjusting your density in the RIP?
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If you uncheck the color correction in the Print
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TAB, you get a very saturated and heavy ink in the surface of the media and
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you will get ink drying problems and dot gain. That is why you have to
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adjust the density of the ink and try to get the best possible color with
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less gain.
Normally this adjustment would be the function of the output profile.
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Since it is a good start of getting the printers profile to uncheck the
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color correction, so I did and ended up wasting much paper and ink. Until
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now, I still have no success regarding the matter.
What profiling software and, if so, what spectrophotometer or
colorimeter are you using to create your output profiles? (FYI to
profile the printer using one of the two expanded inksets, profile as
an rgb device.)
With RCC ver 3 (I haven't received my ver. 4 yet!) there are two
color correction steps in the RIP: input profiles and Output. It then
makes sense to either leave the input function on with profiles
matching your input file so your color table input begins at the
right point. Output is pretty much based on the media you are using.
All the profiles provided are for Roland Media and yield pretty good
results from their default setup of: media (their profile), image
rendering (perceptual), vector rendering (spot). I assume most of
these profiles were produced specific to their media using these
defaults because when I step into the world of relative and absolute
colormetric I get variances I have yet to fully understand.
If you turn off color correction at the input stage your files are
being output from default color tables directly relative to the
default ink density values of the RIP as it was written, not the
values representative of the file itself.
The only way I know to turn off output color correction is to remove
all the output profiles from the ColorChoice ICC profiles folder to
set the media output to None. Image and Vector rendering intents will
still happen depending on your choices.
So...if you are turning off color correction in RCC ver.4, exactly
how are you doing this?
And if you are creating your own profiles I assume you get more
accurate results with Input ON, Media output NONE, relative (or
absolute) for image rendering, relative (or absolute) for vector
rendering.
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Though I tried using the
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profile I made and tried to make color matching using Photoshop Colorsync
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Filter, the image is quite close to my dysub prints. Even during my profile
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generation, It seems that the color space of FJ-500 is also smaller than of
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my dysub and Press when I'm suppose to get a larger color space because I'm
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printing in 8 colors.
My understanding is 8 colors represents the inksets mounted in your
printer, not the sets used to actually print. i.e. a hexachrome
(cmykOrGr) profile set will output cmyk and files meant for cmykOrGr
data, a cmykLcLm set will output cmyk and files meant for cmykLcLm
output. The reason both output cmyk is because:
a) files containing only cmyk data will RIP as cmyk because there is
no data to be mapped into the other two gamuts.
b) the cmyk data in each of the media profiles is relatively the same
when outputing cmyk data. What diferentiates Hex from LcLm is how
they map the out-of-gamut data from file types containing data
outside the cmyk gamut.
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I satisfied with the printers capability to print images using RGB files.
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But getting it to match my proofers and press output, I'm still hanging.
We're still waiting for our PrintOpen ver 4. for MAC from Heidelberg
to take us another step closer to this. From what I do understand:
most of the existing output profiles for Roland media were created
using LX/ED screen patterns not taking in press dot gain/loss. If
anyone knows how best to characterize and profile using angled screen
output, we would appreciate a leg up.
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Anyway, I hope you can give me your opinion on the matter of color
management.
Can't live without it if you live to print, and it just keeps getting
better all the time.
--
Joel Johnstone
designtype
Winnipeg Manitoba Canada
email: work: email@hidden
color geek in residence, reality notwithstanding