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I can't provide a book as reference, but my real-world experience tells me that sRGB vs. Adobe 98 makes very little difference when the final output is offset printing. I've tried it both ways on high-end projects (sheetfed, #1 sheet, annual reports.)
When preparing images for offset output, you'd be working in soft-proof mode using the CMYK output profile, effectively negating any advantage that a wide-gamut monitor would afford you.
The two greatest factors in determining the success or failure of offset output are:
1) The skill of the person preparing the files, and
2) The quality of communication between that person and the pre-press/press folks.
>A photographer had asked me, whether the offset
>print reproduction of his (originally) RAW photos
>would be improved if he used AdobeRGB(1998)as
>working space and an expensive monitor with
>AdobeRGB gamut, instead of generally sRGB.
It seems to me that
1. Changing your monitor won't improve reproduction on paper UNLESS
the old monitor means you make bad decisions in editing or accepting
2. These RAW photos must have some (actual or implied colour space).
What is it? If it is AdobeRGB already, then there is nothing to
change. If it is sRGB already, then the gamut compression already
happened, and converting to another space won't put them back. If
anything, all you'll do is reduce the number of distinct colours
3. IF a camera allows a profile to be chosen before photographing,
then you'll get a wider gamut from Adobe RGB than sRGB, of course.
thanks for your statements. My opinion as well.
My suggestion to the photographer: use mainly
sRGB, and aRGB (AdobeRGB(1998) in some cases
(food, technical products, cloth) but hardly
for landscapes (main field of the photographer).
thanks. The photographer and I are using Nikon
Capture. The RAW photos can be opened, manipu-
lated and saved in 'any' color space, for instance
sRGB or aRGB. A RAW photo contains IMO data
from the CCD array. These are made visible on
the fly for the monitor.
The other question is this: aRGB on an sRGB
monitor means partly blind editing. Is it worth
to purchase a very expensive aRGB monitor ?
Best regards --Gernot Hoffmann
sRGB will clip some cyans, blues and greens, and a small slice of yellow that can be reproduced inside the Euroscale Coated space. But, in my opinion, they are not that significant. ARGB contains all the colors you can get using Euroscale. Either way, blues will generally be weak.
I have used both ARGB and sRGB in jobs sent to press on coated stock, and always used a standard monitor without any surprises or issues. No need to buy an expensive ARGB monitor based on my experience (hundreds of jobs sent to press). For press work, I would avoid wide gamut editing spaces, but you already know that.
I agree with both Rick and Aandi. I'd stick with sRGB for most images and reserve ARGB for your your most colorful images. The smaller the editing space, the more gentle the conversions.
A good way to check it out is to simulate your press profile on your inkjet using good quality, high gamut coated paper (semigloss or semimatte work nicely).
Hope you are well.
>The RAW photos can be opened, manipu-
>lated and saved in 'any' color space, for instance
>sRGB or aRGB. A RAW photo contains IMO data
>from the CCD array. These are made visible on
>the fly for the monitor.
The CCD does have a color space, even if no profile is made available.
Knowing the properties of that space (such as the gamut) can help you
make better decisions.
we agree. Thanks (though I didn't want to enter
into a discussion about opinions, but as long as
we agree it's OK ...).
who knows the gamut of a digital camera without
measuring it ? And even then, this measured gamut
depends on lighting, target and intermediate color
In the context of my basic questions: no,it's
not necessary to know anything about the gamuts
of modern cameras and scanners. The gamuts exceed
always at least in some regions the sRGB volume.
Therefore the (on the first glance) reasonable
recommendation: use aRGB, and the nonsensical one:
use ProPhotoRGB for average stuff.
It remains to be shown, how 'average' images are
printed, based on original aRGB data and then reduced
to sRGB. By offset it's too expensive, but it can
be shown by an inkjet. The application is in this
case landscape photography.
Best regards --Gernot Hoffmann
Can't speak for the rocket science, but I just had one of these wide-gamut monitors on an 8-core Mac Pro, and ended up returning it for a 'standard gamut' NEC because of over saturated reds on the Mac browsers...includes link to Apple archive quoting Carl Lang on this subject you may find interesting:
>who knows the gamut of a digital camera without
>measuring it ?
But it seems to be that measuring it (and I have no suggestions of
how) would give you useful information. Having a profile for them
would allow your raw data to remain raw, with maximum number of
>And even then, this measured gamut
>depends on lighting, target and intermediate color
I don't see that. It seems to me that the gamut comes directly from
the optical properties of the CCD. Lighting affects the colours coming
in the lens. There are surely neither target nor intermediate color
spaces if the data is truly raw.
My concern here is, I will admit, theoretical (colour science), not
from the point of view of a photographer.
thanks for your informations. Now let's think
about the argument 'in a wide gamut color space
we have larger color distances between 1 bit
Correct, but didn't we use (I'm still doing it)
8bpc images in the working space AdobeRGB(1998)
for many many years ? Very satisfying, therefore
it cannot be wrong to send these data directly
(or with very tiny changes) directly to such a
The problem how to show raw sRGB data on an aRGB
monitor can be solved, for instance like this:
1) Adjust the monitor visually by monitor controls
very near to aRGB.
2) Calibrate and profile for aRGB, but don't use
for instance Eizo's ColorNavigator. Do it in
the traditional way, which results in modified
graphics card LUTs.
3) Calibrate and profile again for sRGB, without
changing the monitor controls .
Choose the respective profile by GMB Display Profile,
which defines the system monitor profile.
Load the respective profile by GMB Calibration Loader,
which affects the LUTs.
Check LUT contents by GMB Calibration Tester.
The aRGB mode should cause small deviations from
the straight lines, the sRGB mode larger.
The disadvantage is that one has to choose the mode
IMO a good argument for sticking to sRGB monitors ..
I had given a link to a doc which describes the
whole workflow for camera calibration, which delivers
as well a kind of gamut description.
The calibration is valid for fixed camera settings
and fixed lighting (here for the reproduction of
The three sensor types R,G,B may have well defined
spectral sensitivity functions, but results appear
always after a multiplication by the light spectrum,
which is not flat and for fluorescent light spiky.
There are shown gamuts (planes L=constant) which
differ, depending on the intermediate data format,
which is in this test, one after the other, sRGB,
aRGB and pRGB=Prophoto.
These gamuts are not identical. The targets (two
different were used) are NOT wide gamut targets
(like some printed spot inks). Thus the indicated
gamut is IMO to some extend extrapolated, an
educated guess by the calibration system.
Best regards --Gernot Hoffmann
>> The problem how to show raw sRGB data on an aRGB
monitor can be solved, for instance like this:...
You should pass that along to Eizo. Two levels of Eizo tech support and their top Color Graphics Specialist couldn't answer the theory HOW their wide-gamut panels and X-Rite profile will display untagged sRGB on a Mac (even with the page I linked to simply mouse over and witness the phenomenon).
That's WHY I passed on the Eizo monitors and went with an 'sRGB' NEC 24" side car to my Apple Cinema 30" so I am glad there is a good argument for sticking with them.
Unfortunately (or fortunately) my pea brain power limits my comprehension of yours and Carl Lang's discussion and thus I am stuck with standard tools and software to build my monitor profile, but I always like reading your stuff, Gernot.
I've tested my suggested workflow for using
the same monitor Eizo CG19 alternatively for
D65 and D50 calibration.
D65 is my standard, the monitor is manually
adjusted near to, with little variations in
the graphics card LUTs.
D50 requires then more changes for the LUTs,
which is theoretically bad because of the reduced
number of levels. D50 is for tests only.
All this by Eye-One Pro and ProfileMaker, standard
tools, not using ColorNavigator.
Best regards --Gernot Hoffmann
Thanks, if you even get one of those wide-gamut Eizos on a Mac OS X Safari browser and can look at the sRGB tagged/untagged rollover, I would be interested in hearing how much saturation jump you see in the untagged (and if the aRGB rollover doesn't change much).
I suspect a standard X-Rite Eye-One Display2 profile will show the same goofy reds on the Eizo that I saw in the Dell model...but seeing is believing.
The rollover changes on that page of yours are readily noticeable in Safari on my accurately calibrated and profiled CRT monitors (currently a LaCie Electron22blueIV and a Mitsubishi DiamondPro 2070SB).
If I understand your question correctly ie printing from a sRGB image and aRGB image would there be a difference? then the answer is yes.
I have in one of the magazines that I was working on got an sRGB image which I converted to Fogra 27L (cmyk color space) and proofed the image the proofing clearly showed the image as dull and kind of life less for the second step just to see the difference I assigned aRGB profile (the difference was huge) and converted to Fogra 27L color space I proofed the image again to verify the results, there was a huge difference between both the results aRGB looked a lot better.
I viewed the image on a wide gamut Quato monitor, the advantage I feel was that I got a very good match between my monitor and my print (basically I was seeing aRGB representation of color in Fogra 27L color space, theoretically the color of color does not change when the colorspaces are changed correctly), I feel that the monitor did make a few decision making points kind of simpler for me (atleast).
What I presume is that sRGB being a smaller color space is unable to give that extra saturation that aRGB was able to deliver. If you are interested I will try and find the data and send the proofed sample along with the image.
> I have in one of the magazines that I was working on got an sRGB image which I converted to Fogra 27L (cmyk color space) and proofed the image the proofing clearly showed the image as dull and kind of life less for the second step just to see the difference I assigned aRGB profile (the difference was huge) and converted to Fogra 27L color space I proofed the image again to verify the results, there was a huge difference between both the results aRGB looked a lot better.
What you saw is due to faulty color management. With properly color managed files that are destined for CMYK output, there will be little-to-no difference between starting with an sRGB file vs. an Abobe98 file.
"I assigned aRGB profile (the difference was huge) and converted to Fogra 27L color space I proofed the image again to verify the results, there was a huge difference between both the results aRGB looked a lot better. "
To add to what Rick said, what you've done is assign a different meaning to the numbers when you assigned aRGB to the sRGB image. Of course it's going to change the appearance. Next time, make a copy of the sRGB image and then convert that to aRGB before converting to your output. Better yet, start with a bonafide aRGB image and convert a copy of that to sRGB, then compare those two. As Rick say, there will be very little if any difference.
I would like to mention that, since the image starts off as Raw, using sRGB could clip saturated detail due to its inherent gamut limitations, whereas AdobeRGB or ProPhoto RGB may be able to retain it. Of course this depends on image content: some images will be affected, others not as much or perhaps not at all.
As for the offset print reproduction being improved if one uses "an expensive monitor with AdobeRGB gamut", that is not correctly put, in my opinion. Offset reproduction is not affected *directly* by the monitor's quality -- though one could say that lower-quality monitors may cause the operator to miss or overlook or improperly assess saturated detail in the image, which in turn may *indirectly* affect the quality of the output on press. But there are ways to limit the extent of such errors in judgment even when using these lesser displays.
Also, for added safety, owners of lower-quality monitors ought to make it a routine practice to double-check the results of their image correction by producing a cross-rendered inkjet proof, with the CMYK output profile as a target.