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Color Mgmt...
Advance PhotoLabs guide to
Color Management on the Lightjet 5000
About this guide:
This is not intended to b a definitive guide to color
management, but is a good starting point for users that
would like to get up and running and receive our economy 1st
no file intervention pricing, and those willing to take
responsibility for their own color management. At this
preferred rate, we image your prepped, color managed and
profiled file directly to the Lightjet without opening it.
Our Chemistry is checked and adjusted throughout the day and
each roll of media is calibrated in the Lighjet. We
guarantee tight processing tolerances and most importantly,
exceptional repeatability so you file printed 2 months from
now will look exactly as the one you printed today.
Advance PhotoLabs color management overview:
A color managed workflow is crucial for maintaining
accurate color throughout the image creation process. With
ICC profiles, there is now an industry standard for
maintaining accurate color between users, printers, and
vendors. Users are now able to specify input, working and
printing color spaces, to maintain accurate color throughout
the entire process. The implementation of ICC profiles is
revolutionizing the printing industry with predictable
results. Advance PhotoLabs tight linearization of the
Lightjet process and calibration closes the loop further
with unmatched repeatability.
Color Spaces Overview:
The term spaces and profiles are often used
interchangeably . While they are basically the same, spaces
usually refer to known widely accepted working color spaces,
which are very neutral balanced, while profiles are custom
built around a monitor, printer or scanner. There are many
different types of color spaces (profiles) Images get
converted several times between spaces in the creation to
print process. These spaces include: input, working, viewing
and printing.
The idea is to utilize the most appropriate spaces for
your intended output or use. Most of the time, your input
space is determined by the scanner, your viewing space is
determined by your monitor and monitor calibration, and your
print profile is determined by the printer (In this case,
Advance PhotoLabs Lightjet profile). The working space is up
to you...Ideally, you want to choose a working space that
can utilize the entire color gamut of your scan or original
file before converting it to the printer space (Lightjet
profile). This working space is where you make any
adjustments to your file and save any native version before
profiling to the Lightjet
Wide gamut working spaces are able to retain and produce
a wide range of color from the input file, while narrow
spaces may clip the color of your scan or original. This is
why we recommend Adobe RGB 1998 when possible. This is a
wide working space and can encompass the entire printer
gamut . It has proven to work well with the Lightjet.
Profiling to the Lightjet overview:
Profiling for the Lightjet is simply converting the
working color space, to Advance PhotoLabs color space
(profile)
While the profiling process is relatively simple, there
are areas that need to be set up before the conversion can
begin: These are
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Monitor Calibration
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Color Settings
-
Color Management Policies
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Conversion Options
-
Profile Location
Monitor Calibration:
In order for a monitor to be of any use when adjusting a
file, it needs to be calibrated to a Universal standard
(monitor profile). Once calibrated to this standard, file
changes are accurately represented through the monitor
profile on screen. This monitor calibration (profile) is a
temporary conversion for viewing and adjusting only. It
should not be used as your working RGB space (see working
color RGB setup)
Calibrating your monitor can be done several different
ways. There are many third party companies that sell
measuring devices and software for accurate monitor
profiles. While we recommend such devices, they can get
costly, and are not absolutely necessary to get you started
in the profiling process. I must stress however, that any
weak link, such as a poorly calibrated monitor, will make
color accuracy virtually impossible. With that said,
Photoshop comes with it’s own modest utility, Adobe Gamma.
It is a visual and very subjective calibration process, but
can get you started with generating monitor profiles. We
recommend initial settings of 2.2 gamma, and D65 temp for
Lightjet printing. Please refer to Photoshop’s “Help”
menu for Information on using “Adobe Gamma Utility” for
actual color calibration. It has a wizard function that will
walk you through it.
Color Settings-RGB Setup:
Before color correcting or profiling, you must first
specify your working color settings and preferences within
Photoshop. This is fairly simple. Go to edit/color settings
and in the section boxed off for working spaces, go to the
RGB drop down selection, and choose Adobe RGB 1998 . Hit OK
and you are now working in this color space. The Lightjet is
an RGB device, so ignore the other drop downs (cmyk and
gray) .
Color Management Policies:
On this same screen, set the RGB to preserve embedded
profiles. Also, check ask when Opening for profile
mismatches, missing profiles and pasting.
Conversion options:
While still in the color settings window, click the
advanced settings check box near the top. This adds the
conversion options to the settings window. Choose Adobe for
engine and perceptual for intent. We recommend checking the
black point compensation box. The dither option will add
noise and may only be helpful on smooth gradations. Do not
adjust any of the advanced controls.
Profile Locations:
Keep in mind that when you download a profile, it does
not reside inside the application you are working in ie;
Photoshop. It resides on your system drive. It also depends
on the operating system you are using. The locations for
different operating systems are found on our Lightjet
page along with the profiles. They are very simple to
install. For example: in Windows XP, you click the profile
for the paper you want your job printed on. Then select save
and place it on your desktop. Go to your desktop and right
click the profile. At the top it will say install profile.
Click this. The profile is saved where all your other
profiles reside. In this case, it is in my
C:/windows/system32/spool/drivers/drivers/color. Once this
is downloaded, go back to Photoshop and back to the color
settings window (edit/color settings) . Go to the working
spaces section and click the drop down window for RGB.
Select load RGB from the drop down, and click on the profile
you just downloaded. Hit load, and you will notice that it
shows up in the RGB working space. You can be assured that
you have properly loaded the profile. Now go back to the
correct working space (Adobe RGB 1998).
Okay, now actually doing the file prep and profile
conversion
Save your working version: You will also make a
second file called the print file. Any changes or
modification should be done on your working file and a new
print file produced from it. We recommend using adjustment
layers within Photoshop so file integrity is maintained as
much as possible.
Set the file resolution for the Lightjet:
The lightjet prints at 304.8 DIP (res 12) regardless of
Photoshop file settings. This means that your file needs to
be at 304.8 dpi at your output size or we can have the
Lightjet interpolate your file up or down by using it’s
hardware interpolator. (it’s superior to Photoshop’s
interpolator) Please let us know if you want us to do this.
For example, “my fileis set up for 8x10, please print at
16x20” You will get excellent results between 200 and
304.8 dpi at full output size. You will get good results all
the way down to 150 dpi at full output size. Below this and
images start to fall apart, pixilate or blur.
Flattening your file for the Lightjet: We can only
accept flattened Tiff files with no layers, alpha
channels, path or file file compression. This includes LZW,
ZIP, Stuffed and any other. Byte format doesn’t matter.
Sharpening for output: Do not save unsharp mask on
your working file since sharpening effect will change
depending on your print size.
Borders: If borders are needed, you should add them
using canvas size. If white borders are used, you should
add a 3 pixel black inside stroke (select/all, then choose
stroke from the edit menu). This way we know where to trim
when printed on the white roll of paper. Added borders of
course take more paper stock therefore included in the
price of the print.
Convert to profile: At this point, you need to convert
from your working space to the profile you downloaded.
Simply go to edit/convert to profile. If you have
the preview box checked, you can see how the intended
printer space will map your colors in the conversion to
the printer.
Perceptual rendering intent seems to work best for
photographic Lightjet output. However, relative
colormetric may be better on certain images. Use the
preview check box and toggle back and forth between
intents to see which best produces the most desirable
results. Of course, this is limited by color the monitor
can simulate. We recommend checking black point
compensation. The dither box may also help prevent banding
on smooth gradations by introducing a slight amount of
noise.
Writing to disk: Save your final output file under
another name so you do not overwrite your working file. In
order to qualify for this preferred pricing, you must burn
your flattened RGB Tiff file to standard ISO 9660 format
(this is easily done in your burning software if it is not
already set as such) Save the tiff under PC format. We can
also accept in DVD format either DVD+R or DVD-R.
Good luck and if you have any questions, please free to
call us at 914-693-0778. We are open 7 days a week.
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