[Scribus] How do I do color correction

[Dwain Alford]

On 3/6/07, Hal V. Engel <hvengel at astound.net> wrote:
>
> On Tuesday 06 March 2007 10:11, Dwain Alford wrote:
> > i have an epson stylus photo 1200.  it has a black cartridge and a 6
> color
> > color cartridge.
>
> The 1200 series has 6 inks total including the black cart not
> seven.  Probably
> a typo.



my bad.  somtimes i can't keep those details straight.

> i have fought with getting what is on the screen to the
> > paper since i have had it, but i finally figured it out.
> >
> > now i am on a windows os, so your installed profiles may be different,
> but
> > i do believe that the srgb color space (same as srgb iec61966-2.1) is
> > available on all operating systems.  one other note, kodak and hp offer
> a
> > srgb iec61966-2.1.  in fact, on my system, the srgb color space profile
> is
> > from hp and the srgb profile is from kodak to be used in a d65 monitor
> set
> > up with a gama of roughly 1.8.
>
> sRGB is an approximation of a monitor calibrated to gamma 2.2 and
> D65.  Not
> gamma 1.8 which is a now long obsolete Mac standard.  In addition, most
> CRTs
> have a native gamma between 2.3 and 2.5 so even sRGB will be incorrect for
> most CRTs.



according to the kodak file i have on my machine,  what i quoted came off
that file's information.

>
> > when available i set my graphics software (all of them) to srgb
> > iec61966-2.1for the rgb color space.  i use the swop v2 setting for
> > cmyk (this setting
> > depends on the color profile of your commercial printer, match it and
> > you're in heaven, nirvana, elysian fields or any other good place you
> want
> > to be). inkscape uses a flavor of srgb iec61999-2.1.
> >
> > now for the hardware.  i set my printer to the srgb color space profile.
>
> As you point out above you are on Windows.  On Windows the system default
> color space is sRGB and all devices (printer, video...) using the default
> driver settings are supposed to be sRGB.  This of course is not always the
> case (in fact it seldom is) and users who understand color management do
> not
> use the default driver settings for printing in their color managed work
> flows.  Why? Because in the default mode the drivers do all sorts of
> automatic stuff that make them unsuited to a color managed work
> flow.  That
> is the results are unpredictable unless all of the automatic trickery is
> turned off.



that's why i set srgb eic61966-2.1 as my default for all hardware and
software.  and like i also said, the proof is in the pudding or the print as
it is, i have had no problems with the commercial printers i have used with
my current settings.  this is the icc profile recommended by the icc and
they have two srgb icc profiles, one for relative colorimetric with no black
point compensation and one for perceptual color rendering that has black
point compensation.

i checked the file information on the one with no black point compensation
was issued by hp.

If you go to the Epson download site you can get a set of profiles for many
> of
> the Epson printers including the 1280/1290, R2400, R1800, R800.....  I
> don't
> know about the 1200 but you might want to check.   In addition there is a
> manual that is part of the download that describes how to use these
> profiles.
> That manual says to use the no color correction mode (IE. turn off all of
> the
> automatic stuff) when using the supplied profiles.  In addition the manual
> has very detailed instructions on all of the settings to be used in the
> driver with the profiles.  These profiles are paper and printer specific
> and
> are only valid with the specific Epson papers used to create the profiles.
> These are Epson's directions on how to make color management work with
> their
> printers not mine.  So please have a look.
>
> One other thing to point out is that even though modern ink jet printers
> like
> the Epson 1280 and R2400 have a limited somewhat smallish gamut the gamuts
> of
> these devices have a significantly different shape than the sRGB gamut and
> there is are significant parts of the gamuts of these devices that fall
> outside of what can be represented by sRGB (yellows are the worst case).
> That is you will be getting either clipping of what would otherwise be
> usable
> colors or you will be incorrectly printing some colors if you treat these
> devices as sRGB devices.    The gamuts of these printers are also
> significantly larger than your typical offset printer so profiles like
> ISOCoated are not correct for these devices either.



first, there is no printer profile except the one issued with the driver
update.  second, yellows and especially blues have always been a killer for
commercial printers.  even though there are 5-6 colors of color ink in a
printer they usually print in the rgb gamut; however, because of the
yellows, cyans and magentas these printers, including mine can print in
cmyk, but i doubt the exactness of what a commercial printer can produce.

> now you can go to http://www.color.org and down load icc profiles.  there
> > you will find the srgb profile mentioned above one with and one without
> > black point settings.  read the difference between the two.  i have used
> > them both, but for the hardware i have i stick with the srgb color space
> > profile.
> >
> > my microtek 5900 scanner is set to srgb iec6199-2.1
>
> Why?  It is easy and inexpensive to create custom profiles for your
> scanners
> and cameras.  For flat bed scanners all you need is an ($15 + shipping)
> IT8.7/2 target from Wolf Faust, LProf or ArgyllCMS (Lprof is easier to use
> and both are open source and free), and a few minutes to scan the IT8/7.2
> target and process it into a high quality custom profile.  Both pieces of
> software will create world class input device profiles.  If correctly
> created
> these custom profiles will definitely be better than using sRGB for your
> scanner.  As an example raw processed images from my DSLR have a gamut
> that
> is almost twice as large as sRGB at almost 70% of CIELab.  There is no way
> that I could use sRGB for this device and not either loose (clip) or
> misrepresent almost half of the devices available gamut.  I should also
> point
> out that the IT8.7/2 target itself actually has a gamut that is larger
> than
> the sRGB gamut and most scanners will be able to capture the full gamut of
> the target.


why should i spend the money when my scanner settings deliver the results in
print and on screen that are in acceptable tolerance to the media they are
printed on?  that's what really counts isn't it?  how the object
reproduces?  the way you get there is immaterial, yes?  the proof is in the
pudding, or the printed piece and the satisfaction of the client.


> OK you think your monitor is now correctly calibrated but is it
> really?  Since
> you are a Windows user (same is true for Mac users) you can shop around
> and
> purchase a Pantone Huey for about $50 + shipping (look on ebay).  This
> device
> and the included software will allow you to calibrate and custom profile
> your
> monitor(s).  I think you will be surprised at how much better all of this
> works with a hardware calibrated and profiled monitor.   I know that I
> thought that my visually calibrated monitors were pretty close but I was
> shocked at how much better they were after using a hardware measurement
> device to calibrate and profile my monitors. For Windows and Mac users the
> cost of getting the hardware and software to do this is now so low that
> there
> is absolutely no reason for any Windows or Mac user who is doing color
> critical work to not have this type of device and software.



what i was talking about is a color workflow that would match the monitor
view.  now if you want to spend the money to buy a colorimeter and calibrate
your monitor as it ages, that is your choice, but my method deals in
matching the visual, monitor, with the printer, print, final product.  that
is what we strive for, yes?  by setting your user defined settings of rgb
equally to a percentage you can adjust the density of neutral grey your
monitor displays and the monitor does not need to be color calibrated as the
monitor ages, just the brightness and contrast, because you have established
a neutral, non-color-biased environment to view your work.

you can't control the light a viewer views your printed piece and if you
bias the colors with a monitor setting, you can add to or subtract from the
colors the viewers see.  that is why i have set my monitor, hardware and
software settings the way i have.  how many people view your printed
material under 5500k or 6500k or 9300k lighting?  that is why i have found
that a neutral color monitor calibration works for me.  it doesn't matter
what kelvin light source the piece is viewed under, it all started from
neutral grey, so it always "looks good".

please define color critical.  my definition of color critical is having the
commercial or home printer to come as close as possible to match my screen.
if the printer can come close enough to what my monitor presents, and that
satisfies my client, then that is color critical enough for me.

if the commercial printer can come as close as possible to the red in the
coca-cola logo that coke is happy and that comes close to what i see on my
monitor, then who cares?  i have found in all of my years as an artist,
photographic and other media, that the average person can't tell the
difference between cardinal red and crimson red, and yes, there is a
difference; ask any arkansas razorback or alabama crimson tide fan.

i really appreciate your arguments, hal, but again i say that the proof is
in the print, off the press and off the printer.  if you can get a cmyk
print to come close to the rgb of a printer to the rgb of a monitor then
that's all of the calibration you need.  and on top of that, it's done
without spending a dime on tools and paper profiles.  how many people see
your screen and compare your printed piece to that?  if the end result, the
printed piece, satisfies you and your client, then who cares whether your
monitor or anything else is calibrated about your system?  how close to
perfection your calibration is doesn't matter to your client as long as the
printed piece you produce for him/her satisfies them, yes?

how do i color correct was the initial question.  i supplied a solution that
doesn't cost any money.  make sure that your hardware and software profiles
match.  it certainly doesn't take a colorimeter to do that, does it?  in my
experience, it doesn't.  and besides, if the color critical that you are
shooting for is so exact, then what you see on your monitor should matter
one iota, it's all by the numbers any way, right?

dwain

-- 
dwain alford
p.o. box 145
winfield, alabama  35594
u.s.a.

tele:  205.487.2570
cell:  205.495.5619
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