Nikon D40 or Canon XT or ?

Mike Eisenstadt wrote:
I am interested above all in color accuracy (for doing art
documentation).

For digital photography that is really not the right question to ask or
actually a much, much more complex question, in which the camera only
plays one very small part.

First of all any somewhat non-trivial camera allows the photographer not
only to adjust the white balance (and thus alter the color
interpretation) but also to alter other parameter like saturation,
contrast, etc. in camera, too.
For those who photograph in RAW this will be done later on the computer
instead of in the camera, but again with customized settings.

Second digital photos are typoically processed in picture editing
software, changing hue, saturation, .... , even for each color
individually.

And then the most important factor, which is completely out of the
control of the photographer is the display device. The same file
displayed on different monitors will have different appearances
(unless those monitors and the photographers monitor are both
calibrated, which only very non-experts do).
There is no "color accuracy" even between the same type or brand of
monitor, let alone CRTs versus LCDs.
And it gets much worse for prints, where the printer driver, the driver
configuration, the printer, and of course the ink/toner/... itself
(original or refill? third party?) and the paper play a major role. Just
switch to a different brand of photo paper and you get vastly different
results.

In short: unless you define(!) and calibrate(!) the whole chain starting
with the conversion from RAW to JPEG all the way to the final display on
a monitor or paper there is really no point in discussing color accuracy
of a camera.

jue

In article , Jürgen Exner
wrote:

In short: unless you define(!) and calibrate(!) the whole chain starting
with the conversion from RAW to JPEG all the way to the final display on
a monitor or paper there is really no point in discussing color accuracy
of a camera.

exactly correct. there are a *lot* of variables that matter.

In article
,
Mike Eisenstadt wrote:

I couldnt agree less. It was a pleasant discovery to realize that
monitor callibration is unnecessary,

it's one of the most important things you can do, otherwise you are
flying blind.

that it is a terrible mistake to
do ANYTHING to an image scanned at default values in Photoshop except
for the Levels command (which isn't always necessary), to sum up, keep
everything at default levels and you get a fantastic product.

sometimes the defaults are fine. usually you can do *much* better.

Mike Eisenstadt wrote:
I couldnt agree less.

Now, if you would have had the common courtesy to quote what you are
commenting on then we might have had a chance to know what you are
disagreeing with.

[rest snipped]

jue

Mike Eisenstadt wrote:
On Jul 7, 12:43 pm, Jürgen Exner wrote:
Mike Eisenstadt wrote:
I couldnt agree less.
Now, if you would have had the common courtesy to quote what you are
commenting on then we might have had a chance to know what you are
disagreeing with.

[rest snipped]

jue

Sorry. I lost my Internet connection just when I was clicking on the
Send button.

Here is a reconstruction of what I wrote:

I couldnt agree less. It was a pleasant discovery to realize that
monitor callibration is unnecessary, that usually a mistake to do
ANYTHING to an image scanned at default values in Photoshop except for
the Levels command (which isn't always necessary), to sum up, keep
everything at default levels and you get a fantastic product.

Anecdotal: I made a portfolio of a dozen paintings printed on 8x11.5"
faux photographic paper where the images had great photo realism and
the colors were spot on except for blue.* This was for my roommate who
is a painter. It won her a 2 month stay at a French art foundation in
their countryside. Take pictures on slide film (Velvia now that
Agfachrome is
history) in studio/living room, have them scanned at service bureau to
a Kodak Pro CD, open the weird Kodak format in Photoshop, apply Levels
(which magically removes the strong cyan cast in the scan, a color
cast NOT on the film slide). Print file to my rather ancient albeit
callibrated HP 720 ink jet 300dpi printer.

*Blue is always a problem. Every slide film brand ever sold is/was
unable to reproduce blue paint accurately. This is true also in my
3CCD
Sony camcorder/camera. There are various blues painters use but the
explanation for the blue reproduction problem is above my pay grade.
Also above my pay grade is "fixing" the blue in Photoshop. Everytime a
correction is made in Photoshop a degree of photo realism is lost. You
can get Photoshop professionals to admit that with some prodding. For
me photo realism is what it's all about. Hint: dont crop the edges of
a painting, for it is the edges which provide a great deal of the
photo realism effect. YMMV

Mike Eisenstadt
Austin Texas

Mike...
I know you may be tempted to believe that calibration is a waste of time
but it's not. It is an essential step in 'confirmed' colour correction.
Your blue problem is not blue but violet. Actually Ultra violet and it
comes partly from the UV correction on lens coatings and partly from the
attempt by film makers to mimic daylight in 'clear' film.

I do agree that slide film is an excellent medium to photograph painting
with. When you speak of 'photorealism' this is something you won't get
with a digital image. By the very nature of them, they have prominent
edge separation. Even to the point of making an item look as if it has
been cut and pasted on some backgrounds.

Given all you have said, I think you might be wise to buy a flat field
lens for your existing camera and a film scanner and stick with film. I
still use my old RZ67 for some jobs.

The Kodak system for creating digital images is hardly a good one. It
takes a skilled operator to produce 1st class results. It may be better
for you to take control of that process yourself. You could then scan at
the lpi of the film, instead of what a mini-lab operator thinks is good
enough.

On Tue, 7 Jul 2009 14:22:14 -0700 (PDT), Mike Eisenstadt wrote:

I vaguely remember
reading that photography does not reproduce the colors of some
dyed cloth correctly and that advertising photography of clothing
requires a skilled printer to fix some of the colors.

Are you aware that most of the better cameras allow you to select
the color space/color gamut that is used? Most inexpensive cameras
use sRGB which is pretty much the default that's used for use on the
web. There are others, and Adobe's version, which has a wider color
gamut is the next step up. This is from Nikon's D2X manual, p. 69.
My manuals for newer models don't allow text to be copied, but they
say essentially the same thing :

: sRGB (default) : Choose for photographs that will be printed or used
: “as is,� with no further modification. Color mode II is not available.
:
: AdobeRGB : This color space is capable of expressing a wider gamut
: of colors than sRGB, making it the preferred choice for images that
: will be extensively processed or retouched.
:
: Color Space
: sRGB is recommended when taking photographs that will be printed
: without modification or viewed in applications that do not support
: color management, or when taking photographs that will be printed
: with ExifPrint, the direct printing option on some household printers,
: or kiosk printing or other commercial print services. Adobe RGB
: photographs can also be printed using these options, but colors will
: not be as vivid.
:
: JPEG photographs taken in the Adobe RGB color space are Exif 2.21
: and DCF 2.0 compliant; applications and printers that support
: Exif 2.21 and DCF 2.0 will select the correct color space automatically.
: If the application or device does not support Exif 2.21 and DCF 2.0,
: select the appropriate color space manually. An ICC color profile is
: embedded in TIFF photographs taken in the Adobe RGB color space,
: allowing applications that support color management to automatically
: select the correct color space. For more information, see the
: documentation provided with the application or device.


As for your UV theory, you may or may not be right. However I have
put a UV filter on the lens but I havent noticed any improvement in
the blues. I believe the answer lies in the pigment. I vaguely remember
reading that photography does not reproduce the colors of some
dyed cloth correctly and that advertising photography of clothing
requires a skilled printer to fix some of the colors.

It may be the other end of the spectrum that's causing your color
problem. Most new DSLRs are very insensitive to infrared. Older
models are too sensitive to IR, and this has been described as
causing dark or black fabrics to take on a purplish cast, and this
may be what you've noticed as your "blue" problem. You can get
filters that stop the IR from reaching the sensor, or get a more
recent camera that already filters the IR. I also recall something
about needing to use broad spectrum lighting to produce accurate
colors if you're shooting indoors instead of "apparently" white
light that really doesn't contain the entire spectrum.

On Tue, 07 Jul 2009 10:03:18 -0700, nospam
wrote:

In article
,
Mike Eisenstadt wrote:

I couldnt agree less. It was a pleasant discovery to realize that
monitor callibration is unnecessary,

it's one of the most important things you can do, otherwise you are
flying blind.

Monitors _are_ calibrated. Every monitor which I have bought over the
last several years came with an installation disc which, among other
things, installed a suitable ICM calibration curve into the driver.

I use Windows but I expect the same applies to Apple.

Monitors do drift. I periodiaclly use a Spyder to recalibrate my
monitor but so far my Dell has not perceptibly changed from the day I
bought it.

that it is a terrible mistake to
do ANYTHING to an image scanned at default values in Photoshop except
for the Levels command (which isn't always necessary), to sum up, keep
everything at default levels and you get a fantastic product.

sometimes the defaults are fine. usually you can do *much* better.

The question is 'where'?

I'm currently engaged in comparing the effects of changes in image
processing software and two printers (Epson 1800 and 3800). My general
experience is that I get the best results by turning off color
management in the image processing software and using Epson's printer
calibration data. I can't do as well (let alone better) by fiddling
with things myself.

Would anyone like 43 prints (A4 and A3+) of Piha beach? If you don't
want them, I can let you have about 30 of a very impressive sunset.



Eric Stevens

Eric Stevens wrote:
On Tue, 07 Jul 2009 10:03:18 -0700, nospam
wrote:

In article
,
Mike Eisenstadt wrote:

I couldnt agree less. It was a pleasant discovery to realize that
monitor callibration is unnecessary,
it's one of the most important things you can do, otherwise you are
flying blind.

Monitors _are_ calibrated. Every monitor which I have bought over the
last several years came with an installation disc which, among other
things, installed a suitable ICM calibration curve into the driver.

I use Windows but I expect the same applies to Apple.

Monitors do drift. I periodiaclly use a Spyder to recalibrate my
monitor but so far my Dell has not perceptibly changed from the day I
bought it.
that it is a terrible mistake to
do ANYTHING to an image scanned at default values in Photoshop except
for the Levels command (which isn't always necessary), to sum up, keep
everything at default levels and you get a fantastic product.
sometimes the defaults are fine. usually you can do *much* better.

The question is 'where'?

I'm currently engaged in comparing the effects of changes in image
processing software and two printers (Epson 1800 and 3800). My general
experience is that I get the best results by turning off color
management in the image processing software and using Epson's printer
calibration data. I can't do as well (let alone better) by fiddling
with things myself.

Would anyone like 43 prints (A4 and A3+) of Piha beach? If you don't
want them, I can let you have about 30 of a very impressive sunset.



Eric Stevens

It's all in the colour management control panel of Corel products.
You get the opportunity to make way too many mistakes and when that
happens, it is better to turn off all colour management and rely on sRGB
of the monitor and Epson's own drivers to give you close enough colours.

Strangely enough. Photoshop is easier to understand when feeding the
printer an ICC profile to use than Photo Paint is. Paint Shop Pro isn't
much easier to work with than Photopaint but keep at it, eventually the
seeds will germinate and realisation will bring it's own rewards... In
perfect, not just close colours.

-

In article , Eric Stevens
wrote:

I couldnt agree less. It was a pleasant discovery to realize that
monitor callibration is unnecessary,

it's one of the most important things you can do, otherwise you are
flying blind.

Monitors _are_ calibrated. Every monitor which I have bought over the
last several years came with an installation disc which, among other
things, installed a suitable ICM calibration curve into the driver.

that's based on factory specs which should be good enough for most
people. however, the computer has no idea what kind of display is
attached which is why the display has to be profiled to the operating
system. they're actually two separate things.

Mike Eisenstadt wrote:
On Jul 7, 12:43*pm, Jürgen Exner wrote:
Mike Eisenstadt wrote:
I couldnt agree less.

Now, if you would have had the common courtesy to quote what you are
commenting on then we might have had a chance to know what you are
disagreeing with.

[rest snipped]

jue

Sorry. I lost my Internet connection just when I was clicking on the
Send button.

Here is a reconstruction of what I wrote:

I couldnt agree less.


This repetition still doesn't make it any clearer as to what your
disagreeing with because you still didn't quote anything you are
disagreeing with.

Tracing back the chain of reference headers I can only guess that it's
maybe something I wrote in article
. Which part specifically I
still have no idea because you didn't quote anything..

It was a pleasant discovery to realize that
monitor callibration is unnecessary, that usually a mistake to do
ANYTHING to an image scanned at default values in Photoshop except for
the Levels command (which isn't always necessary), to sum up, keep
everything at default levels and you get a fantastic product.

Limiting the discussion to online viewing of photos, i.e. ignoring
prints for the moment.

Are you claiming that all monitors worldwide, no matter what technology,
how old, which manufacturer, ..., are displaying a specific color in
exactly the same way? I.e. that e.g. the red in a photo that is
displayed on my monitor will be displayed exactly the same way by every
other monitor, too?

If yes, then I suggest you simply walk a computer store and just look at
the monitors on display and compare their color rendering while
displaying the same picture.

If no, then how would it be possible for all monitors to display the
best "color accuracy (for doing art)" as requested by the OP if each
monitor has a different idea about what "red" is? Only one of the many
reds can be the correct red after all, can't it?

That is what calibration is about. You configure your monitor such that
"red" is indeed the same red for everyone who did the calibration. It
has nothing to do with "getting a fantistic product" but It is all about
everyone seeing the product in the same way.

Same applies to prints. Using different paper, different ink, different
printer will result in "red" being printed differently. Therefore again
you have to agree on what does "red" mean and how do I have to configure
my setup to get exactly that "red" that the has been agreed upon to be
"red". This configuration process is called calibration.

jue