Jpeg export changes image

[Bill Sanders-5]

Hello Digikam folks!

I just bought a Nikon D40 digital camera, and I've been shooting in RAW mode
for a while.  I've imported the pictures into digikam, but when I go to
export them to Jpeg, they don't appear the same as Digikam's thumbnails show
them to be.  The jpegs seem to lose a lot of the color and warmth of the
originals.  Is this normal?  Is there a way to change this?  I played around
with the settings in the exporter, but I have to say its pretty much over my
head!

Here's a couple links demonstrating the problem, the first is a screenshot in
digikam of the RAW image, and the second is the output file after export.

http://bobthecowboy.homelinux.net/~bsanders/files/ClareRAW.jpg
http://bobthecowboy.homelinux.net/~bsanders/files/Clare.jpg

Again, sorry if this is common knowledge!  I'm still pretty new to RAW
photography.

I'm a big fan of Digikam, though!

Bill
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[Bill Sanders-5]

Did this message make it to the list?  Or is it just an "obvious" question?

On Tuesday 16 October 2007 9:48:23 pm you wrote:

> Hello Digikam folks!
>
> I just bought a Nikon D40 digital camera, and I've been shooting in RAW
> mode for a while.  I've imported the pictures into digikam, but when I go
> to export them to Jpeg, they don't appear the same as Digikam's thumbnails
> show them to be.  The jpegs seem to lose a lot of the color and warmth of
> the originals.  Is this normal?  Is there a way to change this?  I played
> around with the settings in the exporter, but I have to say its pretty much
> over my head!
>
> Here's a couple links demonstrating the problem, the first is a screenshot
> in digikam of the RAW image, and the second is the output file after
> export.
>
> http://bobthecowboy.homelinux.net/~bsanders/files/ClareRAW.jpg
> http://bobthecowboy.homelinux.net/~bsanders/files/Clare.jpg
>
> Again, sorry if this is common knowledge!  I'm still pretty new to RAW
> photography.
>
> I'm a big fan of Digikam, though!
>
> Bill

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[Arnd Baecker]

Hi Bill,

I think that your question is related to this wish,
  http://bugs.kde.org/show_bug.cgi?id=142055
but I might be wrong.

Guillaume, maybe you can explain things? ;-)

Gilles, couldn't Guillaumes patch(es) go into svn as
libkdcraw 0.1.2 is released now?

Best, Arnd


On Fri, 19 Oct 2007, Bill Sanders wrote:

> Did this message make it to the list?  Or is it just an "obvious" question?
>
> On Tuesday 16 October 2007 9:48:23 pm you wrote:
> > Hello Digikam folks!
> >
> > I just bought a Nikon D40 digital camera, and I've been shooting in RAW
> > mode for a while.  I've imported the pictures into digikam, but when I go
> > to export them to Jpeg, they don't appear the same as Digikam's thumbnails
> > show them to be.  The jpegs seem to lose a lot of the color and warmth of
> > the originals.  Is this normal?  Is there a way to change this?  I played
> > around with the settings in the exporter, but I have to say its pretty much
> > over my head!
> >
> > Here's a couple links demonstrating the problem, the first is a screenshot
> > in digikam of the RAW image, and the second is the output file after
> > export.
> >
> > http://bobthecowboy.homelinux.net/~bsanders/files/ClareRAW.jpg
> > http://bobthecowboy.homelinux.net/~bsanders/files/Clare.jpg
> >
> > Again, sorry if this is common knowledge!  I'm still pretty new to RAW
> > photography.
> >
> > I'm a big fan of Digikam, though!
> >
> > Bill
>
>
> _______________________________________________
> Digikam-users mailing list
> [hidden email]
> https://mail.kde.org/mailman/listinfo/digikam-users
>
>

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[Gilles Caulier-4]

2007/10/19, Arnd Baecker <[hidden email]>:

Hi Bill,

I think that your question is related to this wish,
  http://bugs.kde.org/show_bug.cgi?id=142055
but I might be wrong.

Guillaume, maybe you can explain things? ;-)

Gilles, couldn't Guillaumes patch(es) go into svn as
libkdcraw 0.1.2 is released now?

Guillaumes patch(es) are just delayed and not yet apply. Still in my TODO list of course...

Gilles

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Le vendredi 19 octobre 2007, Arnd Baecker a écrit :
> Hi Bill,
>
> I think that your question is related to this wish,
>   http://bugs.kde.org/show_bug.cgi?id=142055
> but I might be wrong.
>
> Guillaume, maybe you can explain things? ;-)

Hi,

No I don't think help here.
The problem encountered by Bill here is probably the lack of color
management profile that impacts the color rendering far more than (in
fact more acuratlly) setting a right color balance or an auto exposure.

Currently, the raw converter in 8bits will do auto-exposure of the raw,
so it's not problematic, the "lights" will be correct
My patch will help setting more preciselly the raw white balance.

But IMHO, the problem that bill have here is some wrong color rendering
more than exposure or white balance. A color managed view will change
in a non-linear way the color balance of the picture.
Look here for example, and especially the pictures on the right :
http://ufraw.sourceforge.net/Colors.html
Some colors have a big change (look especially at the purple balloon,
the pink shirt, and the yellow trousers), this is what color management
do : some color are renforced, some other are attenuated, and so
picture saturation can greatly change, in order to better fit the real
colors (profile depending on the camera used).

For the story : I generally get the same pale result without using any
color profile with my Canon 400D. Using the right color profile solves
those color fidelity problem :)

Regards,
Guillaume

--
Guillaume Castagnino
    [hidden email] / [hidden email]
GnuPG/PGP key :
http://wwwkeys.pgp.net:11371/pks/lookup?op=vindex&search=0x8AF468AF
Fingerprint : CD52 FE40 9592 BA1E E89D 5FB6 820E 4742 8AF4 68AF
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[Hal V. Engel]

On Friday 19 October 2007 02:01:37 Guillaume Castagnino wrote:

> Le vendredi 19 octobre 2007, Arnd Baecker a écrit :
> > Hi Bill,
> >
> > I think that your question is related to this wish,
> >   http://bugs.kde.org/show_bug.cgi?id=142055
> > but I might be wrong.
> >
> > Guillaume, maybe you can explain things? ;-)
>
> Hi,
>
> No I don't think help here.
> The problem encountered by Bill here is probably the lack of color
> management profile that impacts the color rendering far more than (in
> fact more acuratlly) setting a right color balance or an auto exposure.
>
> Currently, the raw converter in 8bits will do auto-exposure of the raw,
> so it's not problematic, the "lights" will be correct
> My patch will help setting more preciselly the raw white balance.
>
> But IMHO, the problem that bill have here is some wrong color rendering
> more than exposure or white balance. A color managed view will change
> in a non-linear way the color balance of the picture.
> Look here for example, and especially the pictures on the right :
> http://ufraw.sourceforge.net/Colors.html
> Some colors have a big change (look especially at the purple balloon,
> the pink shirt, and the yellow trousers), this is what color management
> do : some color are renforced, some other are attenuated, and so
> picture saturation can greatly change, in order to better fit the real
> colors (profile depending on the camera used).
>
> For the story : I generally get the same pale result without using any
> color profile with my Canon 400D. Using the right color profile solves
> those color fidelity problem :)
>
> Regards,
> Guillaume

I would agree with Guillaume this is a color management issue or rather an
issue with not having color management setup correctly.  It is now fairly
simple to create high quality camera and scanner profiles with minimal cost
using open source software.  All you need is a good profiling target.  IT8
targets are available from Wolf Faust for very reasonable cost (an A4 target
is $40 including shipping to the US and are even less in Europe).  For
software you have two open source options.  ArgyllCMS and LProf.  In general
you will likely find LProf easier to use and that it will produce very high
quality profiles for your cameras and scanners.   Both sets of software also
support display calibration and profiling with a number of commonly available
measurement devices.

Hal
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[Arnd Baecker]

On Fri, 19 Oct 2007, Hal V. Engel wrote:
[...]
> It is now fairly
> simple to create high quality camera and scanner profiles with minimal cost
> using open source software.  All you need is a good profiling target.

So with this  (together with the software) you generate
an ICC profile (*), specific to your camera, right?
Out of curiosity:
According to your experience, how much different are these
from those profiles found on the internet?

Arnd

(*) or several, for each ISO setting, I guess.
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[Hal V. Engel]

On Friday 19 October 2007 13:15:10 Arnd Baecker wrote:

> On Fri, 19 Oct 2007, Hal V. Engel wrote:
> [...]
>
> > It is now fairly
> > simple to create high quality camera and scanner profiles with minimal
> > cost using open source software.  All you need is a good profiling
> > target.
>
> So with this  (together with the software) you generate
> an ICC profile (*), specific to your camera, right?

Not just specific to your camera but to your camera AND processing workflow
including the software used in that workflow.   In fact it is not uncommon
for people to create lighting specific profiles (IE. different profiles for
specific lighting conditions) and on occasion I will make custom shoot
specific profiles if the lighting conditions appear to be unusual at the
location where I am shooting.

> Out of curiosity:
> According to your experience, how much different are these
> from those profiles found on the internet?

What profiles would these be?  Remember that input and output device profiles
are very specific to the device (not just the device model) and the workflow
used with the device.  I don't know of anyplace on the net where I can find
profiles that are specifically for my devices and workflows.

For example where on the net would I find a profile for Nikon D70 images that
are processed through UFRAW using a gamma of 0.45 and a linearity of 0.10?  
What about if I wanted to use different settings is UFRAW such as a gamma of
1.0 (IE. linear image)?   What if the workflow including shooting in unusual
lighting conditions? ....

You might be able to find profiles that are specific to other workflows such
as the profiles from Nikon that are specific to the Nikon RAW software on the
net.  But those profiles will not be correct for my workflow and probably not
yours either.

>
> Arnd
>
> (*) or several, for each ISO setting, I guess.
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[Bill Sanders-5]

So I must confess that I really might be over my head.

So, let me see if I've got this right.

To properly convert to JPG from RAW, I need a color profile.  Is this the same
thing as an ICC file?  This file is different for different cameras, raw
decoders, and lighting situation?

Does this file (or a set of these files?) come with my camera's software in
some way?

And finally, so there isn't a way of just saying "The image as it is presented
in digikam looks just like I want it, make it look like that?"  It just seems
crazy that digikam can display it perfectly, but dcraw (I believe thats the
raw decoder?) produces a wildly different image
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[Gerhard Kulzer-3]

Am Saturday 20 October 2007 schrieb Bill Sanders:
> So I must confess that I really might be over my head.
>
> So, let me see if I've got this right.
>
> To properly convert to JPG from RAW, I need a color profile.  Is this the
> same thing as an ICC file?  This file is different for different cameras,
> raw decoders, and lighting situation?

Same as ICC profile. It is delivered with your camera software. Yes, you
usually have profiles for landscape and portrait photography at least.
>
> Does this file (or a set of these files?) come with my camera's software in
> some way?

Yes, look for *.icc or *.icm files.

> And finally, so there isn't a way of just saying "The image as it is
> presented in digikam looks just like I want it, make it look like that?"
No. digiKam displays the RAW embedded thumbnail, which has been converted by
the camera. That's life with RAW workflow. It is not simpler in any other
software except the camera manufacturer's own SW.
> It just seems crazy that digikam can display it perfectly, but dcraw (I
> believe thats the raw decoder?) produces a wildly different image
> _______________________________________________
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> [hidden email]
> https://mail.kde.org/mailman/listinfo/digikam-us


Gerhard

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[Arnd Baecker]

Hi Hal,

On Fri, 19 Oct 2007, Hal V. Engel wrote:

[... very helpful explanation snipped...]

> You might be able to find profiles that are specific to other workflows such
> as the profiles from Nikon that are specific to the Nikon RAW software on the
> net.  But those profiles will not be correct for my workflow and probably not
> yours either.

Thanks a lot for the detailed explanation - obviously,
there is a lot I have to learn about color management ... ;-)

This brings me back to *my* usual "can't this be simpler?"
(which seems also in the spirit of Bill's last mail ;-).
Well, to do things really right, one needs to create profiles
in the way you explained before.

However, for many users (at least for me) it would be sufficient
(at least to start with) to
  "for my raw file produce an image which looks
   *essentially* the same as the jpg"
The benefit compared to using the jpg are more Bits and
no jpg artifacts (and no sharpening etc.).
((By essentially I mainly mean white-balance and brightness.
Presumably, there is no way (and it would not make sense)
to fully mimick the jpg, as this already may involve
a lot of other post-processing, like levels adjustment,
some filtering, sharpening, etc.; but yes, this "essentially"
is a weak point in the argument ;-))

So the question is, whether for example the available ICC profiles
(e.g. for bibblepro which also uses dcraw) are good enough
to use with digikam, or what could be done (if possible at all)
on the side of digikam to make things work as easy as possible
for the user.
Of course, this will not be the 100% solution you described
(as for example it cannot take the light conditions into account),
but might be ok for many situations ....

Personally, for me the next important step will be to buy
a device (which works under linux) for screen calibration,
as to me this seems my biggest problem in the workflow
of getting reliable prints at the lab.

Thanks a lot for your time and expertise, it is really
very much appreciated!!

Best, Arnd
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[Bill Sanders-5]

Just wanted to say thank you.  This has been a very informative thread for me.  
I'll have to find a windows box and my software, to see if I can get those
*.ic[cm] files.  I appreciate all the help.

Bill

On Saturday 20 October 2007 12:09:51 am Gerhard Kulzer wrote:

> Am Saturday 20 October 2007 schrieb Bill Sanders:
> > So I must confess that I really might be over my head.
> >
> > So, let me see if I've got this right.
> >
> > To properly convert to JPG from RAW, I need a color profile.  Is this the
> > same thing as an ICC file?  This file is different for different cameras,
> > raw decoders, and lighting situation?
>
> Same as ICC profile. It is delivered with your camera software. Yes, you
> usually have profiles for landscape and portrait photography at least.
>
> > Does this file (or a set of these files?) come with my camera's software
> > in some way?
>
> Yes, look for *.icc or *.icm files.
>
> > And finally, so there isn't a way of just saying "The image as it is
> > presented in digikam looks just like I want it, make it look like that?"
>
> No. digiKam displays the RAW embedded thumbnail, which has been converted
> by the camera. That's life with RAW workflow. It is not simpler in any
> other software except the camera manufacturer's own SW.
>
> > It just seems crazy that digikam can display it perfectly, but dcraw (I
> > believe thats the raw decoder?) produces a wildly different image
> > _______________________________________________
> > Digikam-users mailing list
> > [hidden email]
> > https://mail.kde.org/mailman/listinfo/digikam-us
>
> Gerhard

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[Hal V. Engel]

On Saturday 20 October 2007 00:17:33 Arnd Baecker wrote:

> Hi Hal,
>
> On Fri, 19 Oct 2007, Hal V. Engel wrote:
>
> [... very helpful explanation snipped...]
>
> > You might be able to find profiles that are specific to other workflows
> > such as the profiles from Nikon that are specific to the Nikon RAW
> > software on the net.  But those profiles will not be correct for my
> > workflow and probably not yours either.
>
> Thanks a lot for the detailed explanation - obviously,
> there is a lot I have to learn about color management ... ;-)

Color management is non-trivial and the learning curve is fairly steep.  So
don't expect to understand this stuff in just a few hours.  I should add that
it is normal to feel like you are in over your head when you first start
trying to understand it.  Hang in there it will get better.

>
> This brings me back to *my* usual "can't this be simpler?"
> (which seems also in the spirit of Bill's last mail ;-).
> Well, to do things really right, one needs to create profiles
> in the way you explained before.
>
> However, for many users (at least for me) it would be sufficient
> (at least to start with) to
>   "for my raw file produce an image which looks
>    *essentially* the same as the jpg"
> The benefit compared to using the jpg are more Bits and
> no jpg artifacts (and no sharpening etc.).
> ((By essentially I mainly mean white-balance and brightness.
> Presumably, there is no way (and it would not make sense)
> to fully mimick the jpg, as this already may involve
> a lot of other post-processing, like levels adjustment,
> some filtering, sharpening, etc.; but yes, this "essentially"
> is a weak point in the argument ;-))

Also how do you tell any software to "produce an image which looks
*essentially" the same as the jpg"?  The conversion from the sensor data to
the RGB image data is a complex process.  In addition, the camera processed
jpeg images may not be very accurate since many camera manufacturers,
particularly for consumer grade cameras, do all kinds of things to the images
to make them "look better" such as artificially increasing saturation and
contrast.  I would rather have an accurate representation as a starting point
even if it looked a little flat and if I really wanted more saturation or
contrast then I will do these changes myself.

>
> So the question is, whether for example the available ICC profiles
> (e.g. for bibblepro which also uses dcraw) are good enough
> to use with digikam, or what could be done (if possible at all)
> on the side of digikam to make things work as easy as possible
> for the user.

These will be better than using no profile or some generic profile such as
sRGB.  But not as good as using a good custom profile.  So trade off is you
lose a little image quality in return for a little convenience.  You also do
not have the cost of buying a profiling target.

> Of course, this will not be the 100% solution you described
> (as for example it cannot take the light conditions into account),
> but might be ok for many situations ....
>
> Personally, for me the next important step will be to buy
> a device (which works under linux) for screen calibration,
> as to me this seems my biggest problem in the workflow
> of getting reliable prints at the lab.

At this point almost any device you can buy is supported although some of the
support is very new and may still have some bugs.  LProf should have support
for Spyder 2 and Huey devices in CVS in the next day or two.  There is
currently support for DTP-92, DTP-92, and all of the EyeOne meters as well as
some older devices like the Spectrolino.  In addition, there is even support
for a DIY meter if you are handy with a soldering iron.

You can get Huey meters on ebay for around $50 plus shipping and EyeOne
Display Lt meters can be found on the net for $130 to $140 and sometimes
cheaper if you shop around.  The DTP-94 is discontinued but you may find one
on sale cheap someplace and most consider this to be a better meter than the
EyeOne Display 2 and LT.  For the record the only real difference between an
EyeOne Display 2 and an Lt is the "unlock" string which allows the vendors
software to pretend that these are really different devices.

Regardless of which open source software you use to calibrate and profile your
displays this software will also allow you to profile your cameras and
scanners.  So you should consider buying a profiling target so that you can
fully close the circle.  

>
> Thanks a lot for your time and expertise, it is really
> very much appreciated!!
>
> Best, Arnd
> _______________________________________________
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