color calibration question
peter
profile, that's why digital cameras all have sRGB profile as default.
What happens after the monitor is calibrated using those spyder calibration
device and the color profile loaded into windows? Does it now have a perfect
sRGB profile (which has a gamma of 2.2), or does it now have gamma of 1.0
(perfectly linear)?
I'm hoping it's the first case because that means all digital photos would
look correct on the monitor. If it's the 2nd case, that means all digital
photos would need to be converted to the gamma=1.0 color space before it
looks good on the monitor.
Roy
news:pJI6e.11310$H_5.9871@trnddc01...
Uncalibrated Monitors do not approximate to the sRGB Profile. Just have a
good look next time you are in one of the discount warehouses, you should be
able to see that the monitor colours all look different. It is unfortunate
that the colour system, ( it is not a profile), used by monitors is called
RGB, hence the confusion.
Not all Cameras convert their output to sRGB, the better ones now include
Adobe RGB as an option.
sRGB, Adobe RGB, Pro-photo RGB, etc are all Working Space Profiles. They
define the numerical values associated with particular colurs and shades of
colours, and are used by Graphics Programs to do the calculations required.
sRGB has a narrower range of colour (Gamut) than Adobe, and Pro-photo has a
greater range.
A Monitor Profile is used by the Program to convert the numbers in the
Working Space Profile, so that the colours seem on the screen are accurate.
The idea is that, an image should look exactly the same no matter which
Calibrated Monitor it is being displayed on.
Printer Profiles are used by the Program to convert the numerical values, so
that the colours on the Print will be accurate. The idea is, again, that an
image should look the same, no matter which Calibrated Printer is used to
make the Print.
There are, of course, variations between the Ideal and Real Life.
Printer Profiles are for a Specific Printer, using Specific Inks and
Specific Paper.
Epson do supply profiles for their Printers, using Epson Inks and Epson
Papers, and so do other Printer companies. Kodak, Tetenal, Olmec, etc,
will supply Profiles for certain of their Papers, in Specific Epson & Canon,
etc, Printers using the Original Ink sets. These types of profiles are often
called "Canned" profiles, and are fairly accurate most of the time.
Colour Management is quite a difficult subject, and understanding is not
helped, by a lot of the half-baked advice you may receive from non experts.
"My camera works in sRGB, so I set my Printer to sRGB" is a common one.
Roy G
Paul Mitchum
[..]
> sRGB is a working colorspace, not a monitor colorspace. It was designed
> not to exceed the worst case gamut of about 40 different cheap monitors. A
> good monitor, properly calibrated should have a considerably larger gamut
> than sRGB. I recommend shooting and working in Adobe RGB 98 and only
> converting to sRGB for web work (browsers are all designed for sRGB
> gamuts)
Just a nit with your parenthetical:
Many web browsers respect an embedded ICC profile, and many also respect
a ColorInfo rule in CSS (which lets you specify profile and intent). If
there's no profile and no CSS rule, some browsers will use sRGB and some
will use the monitor profile. sRGB is the safest, but additionally
embedding the profile and marking it up in the CSS is the safest of all.
Some info: <http://www.ekdahl.org/kurs/colormanage.htm>
David Dyer-Bennet
> "peter" <nos...@nospam.com> wrote in message
> news:pJI6e.11310$H_5.9871@trnddc01...
>>I understand that uncalibrated CRT monitors has approximately the sRGB
>>profile, that's why digital cameras all have sRGB profile as default.
>>
>> What happens after the monitor is calibrated using those spyder
>> calibration device and the color profile loaded into windows? Does it now
>> have a perfect sRGB profile (which has a gamma of 2.2), or does it now
>> have gamma of 1.0 (perfectly linear)?
>>
>> I'm hoping it's the first case because that means all digital photos would
>> look correct on the monitor. If it's the 2nd case, that means all digital
>> photos would need to be converted to the gamma=1.0 color space before it
>> looks good on the monitor.
>>
>
>
> Uncalibrated Monitors do not approximate to the sRGB Profile. Just have a
> good look next time you are in one of the discount warehouses, you should be
> able to see that the monitor colours all look different. It is unfortunate
> that the colour system, ( it is not a profile), used by monitors is called
> RGB, hence the confusion.
No, actually, sRGB *was* defined to approximate uncalibrated
monitors. That's why it's the recommended profile to convert images
for web display to, for example.
--
David Dyer-Bennet, <mailto:dd...@dd-b.net>, <http://www.dd-b.net/dd-b/>
RKBA: <http://noguns-nomoney.com/> <http://www.dd-b.net/carry/>
Pics: <http://dd-b.lighthunters.net/> <http://www.dd-b.net/dd-b/SnapshotAlbum/>
Dragaera/Steven Brust: <http://dragaera.info/>
David Dyer-Bennet
> 2.2
>
> sRGB is a working colorspace, not a monitor colorspace. It was designed
> not to exceed the worst case gamut of about 40 different cheap monitors.
> A good monitor, properly calibrated should have a considerably larger
> gamut than sRGB. I recommend shooting and working in Adobe RGB 98 and
> only converting to sRGB for web work (browsers are all designed for sRGB
> gamuts) or if your printer expects an sRGB colorspace before the
> printer's profile is applied. I profile my printers and design the
> profiles to expect the larger gamut of Adobe RGB 98 as an input but most
> factory printer profiles probably don't.
However, most online photo-printing places I've looked at want you to
deliver to them in sRGB.
papenfus...@juneaudotmedotvt.edu
: > able to see that the monitor colours all look different. It is unfortunate
: > that the colour system, ( it is not a profile), used by monitors is called
: > RGB, hence the confusion.
: No, actually, sRGB *was* defined to approximate uncalibrated
: monitors. That's why it's the recommended profile to convert images
: for web display to, for example.
: --
IIRC, it was defined using D65 as the whitepoint. Probably 98% of the
monitors out there are currently set to their default white point of 9300K since
"brighter" displays sell better.
-Cory
*************************************************************************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
*************************************************************************
Roy
news:d3j0l9$r1e$1...@solaris.cc.vt.edu...
Hi there.
Please lets not get too much into semantics, over this. As someone said
earlier, sRGB was designed with low end monitors in mind. But an
Uncalibrated monitor, still needs to be Calibrated, even if the Working
Space is going to be sRGB.
Because all Elephants are grey, does not mean that all grey things are
Elephants.
The OP seemed to under the impression that the Profile resulting from
Calibration would be a "perfect" sRGB Profile, when as we all know it will
be an "Output" type of Profile, and will be used to make Convertions from
whatever Working Space is chosen. I was a little concerned that he would
then fall into the trap of using his Calibrated Monitor Profile as a Working
Space. Hence my rather wordy, and not technically exact, explanation.
Roy G
David Chien
sold today have a sRGB mode. sRGB mostly comes out of digicams and
printers. and once you've set everything to work in sRGB, you'll be
surprised! -- instant color matching w/o spending a cent. (Okay, not
100% accurate, but pretty darn close.)
I found this to work the best for me after trying those $$ Spyders and
other color matching/calibration programs.
Why?
1) You'll NEVER EVER get a 100% matching between monitor and print. One
is transmissive, the other is reflective. It is PHYSICALLY IMPOSSIBLE
to make the match exactly -- it's like trying to make a light bulb
(monitor) match the print (printer). Just can't be done because the
print can't glow and shine light like the light bulb.
2) Even if you spend $$$$$ on the color calibration programs and tools,
#1 still is in effect. You will still find yourself annoyed to death
that the print doesn't look exactly like the monitor until you realize #1.
3) Everyone views prints under differing lighting conditions - this
alone will result in color mismatch between what you see on the print
vs. the monitor. You'll have to change out all of your light bulbs for
color standard bulbs if you want to see everything in a consistant way.
(and even here, depends on your choice of reference color temperature
- 5000k 5500k 6000k etc)
As a result of #1 through #3 AND the fact that the human eye's color
response varies minute-by-minute and day-to-day, you'll realize that
unless you're spot checking every print sample in multiple locations
with a color spectrometer to make sure every print is matching intended
colors exactly (or calibrating printers before), you'll notice that one
day, a print may look superb, but the next day, it's not so great.
Add to that the fact that inkjet photo prints (what most home users use)
significantly shift in color and density over the course of a week or
two after the print was made = people pulling hair like crazy. "But the
print looked great the moment it was printed!" they say! only to
discover that by week's end, it's totally different. (due to the
water-based inks drying over time, etc.)
---
The quick & easy way is to simply rely upon the sRGB standard most
makers have agreed upon. They've already calibrated their devices to
that, and like me, you can get pretty close (90% or so) to the true
colors by simply sticking with a sRGB pipeline.
Those that want more can always color manage, calibrate, etc. + change
their light bulbs, use color checkers, etc., but that's usually a very
time consumer and costly step to take knowing that no matter what,
prints won't look exactly the same as the monitor image.
Paul Mitchum
> use...@mile23.c0m (Paul Mitchum) wrote:
>
> > Many web browsers respect an embedded ICC profile, and many also respect
> > a ColorInfo rule in CSS (which lets you specify profile and intent)
>
> Name two; or even one that isn't Mac only.
Microsoft Internet Explorer (the ColorInfo rule is an IE extension to
CSS).
Besides: Why is it that being Mac-only is a disqualifier? Don't you want
your pictures to look good on Macs, especially when it's so easy to do?
Safari, for instance, will use the screen profile for displaying images
without a profile, but it will respect ColorInfo in CSS.
The rule of thumb: Convert to sRGB (if you're not there already) and use
a ColorInfo CSS rule. Not so difficult, and covers all the bases that
can be covered.
Roy
news:d3k1s7$5b3$1...@news.service.uci.edu...
As said in my first posting there is a difference between the Ideal and the
Real World.
And as I predicted right at the end of that posting, you will get told to
set everything to sRGB.
There are some elements of truth in what is being said, but just because you
can not acheive perfection with Colour Management, does not mean that you
should just give up and settle for the mediocre. I happen to think that
Colour Management is beneficial, and also think that my prints demonstrate
it, even though they are not perfect. I have been doing photography too
long to expect perfection.
Judge for yourself in the Computer Warehouses whether all the, "sRGB mode",
Monitors are showing the same colours, then try to guess which one, if any,
is showing the correct colours.
They still need to be Calibrated.
Roy G
David Chien
> Monitors are showing the same colours, then try to guess which one, if any,
> is showing the correct colours.
>
> They still need to be Calibrated.
PC magazines in Japan all have detailed gamut charts for all of the
monitors they review. Some of the most accurate ones have been made by
Eizo and Apple in the past. Here, in fact, if you simply buy a Mac,
you'll get their panels matching the sRGB gamut nearly perfectly.
Anyways, you simply review the charts and you can easily pick a panel
that'll color match sRGB nearly perfectly.
No calibration needed.
Roy
Well, if I was thinking of paying the sort of money that Eizo or Mac charge
for their displays, I would expect them to have been calibrated before
leaving the factory.
As I said, have a look at the colours on the Monitors, which are on display
in the warehouse type outlets, and see the differences for yourself. If
they were all showing similar colour, I would concede you had won the
argument, but they don't.
Roy G
David Chien
> in the warehouse type outlets, and see the differences for yourself. If
> they were all showing similar colour, I would concede you had won the
> argument, but they don't.
Of course!
Why don't they look the same?
1. They all haven't been set to sRGB mode.
2. They all don't have the same brightness. As a result, brighter
monitors will look =nicer= and darker monitors will look =muddy=.
3. Warehouse-type outlets never bother with anything except plugging
it in - no calibration, etc.
4. Most of the 'cheap' non-top tier brand monitors - what calibration?!?
But stick with a decent monitor like Viewsonic or Samsung, and you'll
likely get close to the sRGB gamut w/o spending the $$$ of the EIZO or
Apple displays. The PC magazine charts reflect this fact as well.
---
Anyways, aside from the above, even if the monitor is 80% there or
100% accurate, you still have to eyeball the display and make the best
judgement re: your prints and what they'll look like -- remember, even
if the monitor is 100% accurate to the sRGB gamut, the difference
between transmissive and reflective means even if you're print matches
the sRGB gamut 100%, they still won't look the same. (Think light bulb
vs. picture of light bulb.)
Graeme Cogger
accurately. The gamut simply describes the range of colours a monitor
is capable of displaying, not whether it maps input RGB values to the
correct colour.
In my experience, setting a monitor to sRGB mode is better than nothing,
but not much better!
Paul Mitchum
> > Judge for yourself in the Computer Warehouses whether all the, "sRGB
> > mode", Monitors are showing the same colours, then try to guess which
> > one, if any, is showing the correct colours.
> >
> > They still need to be Calibrated.
>
> PC magazines in Japan all have detailed gamut charts for all of the
> monitors they review. Some of the most accurate ones have been made by
> Eizo and Apple in the past. Here, in fact, if you simply buy a Mac,
> you'll get their panels matching the sRGB gamut nearly perfectly.
Apple's generic Color LCD profile has a significantly smaller gamut than
sRGB. So none of their LCD monitors (they don't make CRTs anymore) will
magically 'be' sRGB.
Here's their Color LCD profile compared to sRGB. The outer wireframe is
sRGB: <http://www.mile23.com/misc/colorlcd_srgb.jpg>
I just calibrated my iBook screen earlier this evening, and it's pretty
close to the generic profile, too.
> Anyways, you simply review the charts and you can easily pick a panel
> that'll color match sRGB nearly perfectly.
>
> No calibration needed.
You can find a monitor with a wide gamut, but it's bad advice to tell
someone to not calibrate their monitor for color graphics works.
It's easy and quick and painless, and printouts of your snapshots will
stand a much better chance of looking like they do on screen.
Paul Mitchum
> use...@mile23.c0m (Paul Mitchum) wrote:
>
> > Apple's generic Color LCD profile has a significantly smaller gamut than
> > sRGB. So none of their LCD monitors (they don't make CRTs anymore) will
> > magically 'be' sRGB.
>
> Pretty much putting MAC out of the professional graphics and photography
> business for anyone that has color quality concerns.
Hehe. That's funny.
Rick
I wish it were. But it's an LCD issue, not just an Apple issue.
I'm seeing more and more horrid "professional" images chock
full of color errors, noise etc, especially in dark shots, caused
by editors and proofers not being able to see these problems
on limited gamut LCDs.
Ron Hunter
graphics and photography places, and a LOT of magazines are published
with them from start to finish.
Professional Mac users often use very large (23") monitors, of the
finest quality.
--
Ron Hunter rphu...@charter.net
Paul Mitchum
That's not a problem unique to Macs, however, is it? An uncalibrated
and/or low-gamut monitor won't provide the best results no matter what
computer it's hooked up to.
That's why what bubba said was funny.
Paul Mitchum
> use...@mile23.c0m (Paul Mitchum) wrote:
>
> > That's not a problem unique to Macs, however, is it? An uncalibrated
> > and/or low-gamut monitor won't provide the best results no matter what
> > computer it's hooked up to.
>
> My point is that without a CRT monitor MAC users will not be able to do
> professional level work. Using other manufacturers' monitors can be
> problematic due to MAC's use of the D5000 1.8 gamma system that is
> essentially incompatible with the way that CRT physics work. Sure, you can
> tweak a CRT monitor to gamma 1.8 but electron guns work at a natural 2.2
> gamma (why everyone but MAC uses it). If you run them at 1.8 you degrade
> their color gamut and get flaky shadow detail.
It's 'Mac.' It's not an acronym.
You can set your Mac to work at 2.2 gamma if you want. There's
justification for using 1.8, and there's justification for using 2.2.
Make two profiles and switch between them when you need to with a couple
mouse clicks. It's not that difficult.
andr...@littlepinkcloud.invalid
> For consumers, simply use sRGB all the way through. Most LCD panels
> sold today have a sRGB mode. sRGB mostly comes out of digicams and
> printers. and once you've set everything to work in sRGB, you'll be
> surprised! -- instant color matching w/o spending a cent. (Okay, not
> 100% accurate, but pretty darn close.)
> I found this to work the best for me after trying those $$ Spyders and
> other color matching/calibration programs.
> Why?
> 1) You'll NEVER EVER get a 100% matching between monitor and print. One
> is transmissive, the other is reflective. It is PHYSICALLY IMPOSSIBLE
> to make the match exactly -- it's like trying to make a light bulb
> (monitor) match the print (printer). Just can't be done because the
> print can't glow and shine light like the light bulb.
Well, the gamuts are different. However, within the common gamut of
monitor and paper, you can get a good visual match, certainly one
that's good enough to judge whether an image is right for printing.
> 2) Even if you spend $$$$$ on the color calibration programs and
> tools, #1 still is in effect. You will still find yourself annoyed
> to death that the print doesn't look exactly like the monitor until
> you realize #1.
I don't agree with this. Since I moved to a fully colour managed
workflow I've had few problems with prints looking wrong. Soft
proofing seems to do what it's designed to do.
> 3) Everyone views prints under differing lighting conditions - this
> alone will result in color mismatch between what you see on the
> print vs. the monitor. You'll have to change out all of your light
> bulbs for color standard bulbs if you want to see everything in a
> consistant way.
All of them? Why? Just the ones you're using to view the proof,
surely.
> As a result of #1 through #3 AND the fact that the human eye's color
> response varies minute-by-minute and day-to-day, you'll realize that
> unless you're spot checking every print sample in multiple locations
> with a color spectrometer to make sure every print is matching
> intended colors exactly (or calibrating printers before), you'll
> notice that one day, a print may look superb, but the next day, it's
> not so great.
That may be true as lighting conditions change, but I've not seen
printers change their colour over time. FWIW, I'm using Epson
printers and Ultrachrome inks.
I think you're underestimating what colour management can do.
> Those that want more can always color manage, calibrate, etc. +
> change their light bulbs, use color checkers, etc., but that's
> usually a very time consumer and costly step to take knowing that no
> matter what, prints won't look exactly the same as the monitor
> image.
As I said, I have seen little unexpected disparity between soft proofs
and the resulting prints. It takes a little experience to get used to
soft proofing, but it does work.
Andrew.
Dave Martindale
>My point is that without a CRT monitor MAC users will not be able to do
>professional level work. Using other manufacturers' monitors can be
>problematic due to MAC's use of the D5000 1.8 gamma system that is
>essentially incompatible with the way that CRT physics work. Sure, you can
>tweak a CRT monitor to gamma 1.8 but electron guns work at a natural 2.2
>gamma (why everyone but MAC uses it). If you run them at 1.8 you degrade
>their color gamut and get flaky shadow detail.
There is nothing special about Apple monitors at all. Their electron
guns have the same gamma as all other CRTs. The *difference* is in the
lookup tables loaded into the graphics card hardware. On a PC, these
are normally loaded so they have no effect, while on a Mac they are
loaded with a function that has a gamma of 1.8/2.2.
So you can connect *any* CRT to a Mac, and get a Mac standard gamma
response. You can also set the Mac to use 2.2 instead of 1.8 if you
want.
Dave
Paul Mitchum
> da...@cs.ubc.ca (Dave Martindale) wrote:
>
> > There is nothing special about Apple monitors at all. Their electron
> > guns have the same gamma as all other CRTs. The *difference* is in the
> > lookup tables loaded into the graphics card hardware. On a PC, these
> > are normally loaded so they have no effect, while on a Mac they are
> > loaded with a function that has a gamma of 1.8/2.2.
>
> Yes, but any time you use an LUT to modify the natural gamma of an
> electron gun, you lose quality.
Then the whole idea of color management using a monitor profile is kinda
out-the-window anyway, isn't it?
> > So you can connect *any* CRT to a Mac, and get a Mac standard gamma
> > response. You can also set the Mac to use 2.2 instead of 1.8 if you
> > want.
>
> I take it that this is a relatively recent ability for Macs (ability to
> use gamma 2.2).
Nope. I'm pretty sure it's ever since they've been color, but definately
ever since ColorSync.