Problems with color when importing a .dng into photoshop cs3 - page 4 - RAW Shooting and Processing - CHDK Forum
« previous next »
Pages: 1 2 3 [4] 5 6 7 8   Go Down

Problems with color when importing a .dng into photoshop cs3

  • 71 Replies
  • 33800 Views
*

Offline vit40

  • ****
  • 276
Re: Problems with color when importing a .dng into photoshop cs3
« Reply #30 on: 10 / February / 2009, 02:16:39 »
Advertisements
In short ...

Color matrix is 3x3 matrix (= 9 numbers), used for conversion of R,G,B values from "sensor color space" to sRGB colors space values (or AdobeRGB), usually used for digital imaging. Those values are written in a exif tag of DNG file, so raw convertor can use them (in case of ACR) or ignore them and use it's own matrix for that camera model (like Picassa I suppose)

Using this kind of conversion, colors look always slightly wrong in red-yellow range - whether red tends towards magenta and orange is ok, whether red is ok and orange tends towards yellow (depends where position of red primary is in CIExy). That's why Adobe finally introduced color profiles in last DNG specification. A profile is a big lookup table, used to additionaly tune colors that were already converted to sRGB using a matrix (actually, this matrix operation is also changed in last specification and additional 3x3 matrix called forward matrix is used)

Were these samples made using last version of CHDK, or you used my matrix for A650 ?
Logged
*

Offline zosX

  • *
  • 37
Re: Problems with color when importing a .dng into photoshop cs3
« Reply #31 on: 10 / February / 2009, 19:59:35 »
I'm using the latest matrix from CHDK. I've been meaning to play with that matrix utitility, just haven't gotten a chance yet. Thanks for the information btw. That is most useful!
Logged
*

Offline ArtDen

  • ***
  • 175
    • dng4ps2
Re: Problems with color when importing a .dng into photoshop cs3
« Reply #32 on: 11 / February / 2009, 00:10:50 »
Quote from: zosX on 06 / February / 2009, 19:06:52
It seems to work great when I import the resulting dngs into Picasa, however when I open the files in photoshop the colors are not even remotely correct and it is impossible to even dial the white balance back in to something usable.
1. Color matrix for a590 was marked as "not good" ( look here: http://code.google.com/p/dng4ps2/source/browse/trunk/src/CameraOpts.cpp ) because it was not calculated properly. It looks like is not possible to calculate it with "jpeg+raw" algorithm of dng4ps2.
2. Dng files from dng4ps2 utility don't contain white point so photoshop can only reconstruct white balance (it does it good not every time). This means you have to correct the white balance manually almost of each photo you edited
Logged
*

Offline Howdy

  • *
  • 21
  • [S5 IS]
Re: Problems with color when importing a .dng into photoshop cs3
« Reply #33 on: 11 / February / 2009, 05:07:27 »
The color matrix stuff is a well known problem with CHDK. I have been fighting with it (without any success) for a very long time. Unfortunately, it is not as easy as one might think... (For a brief introduction, try reading
http://chdk.setepontos.com/index.php/topic,1157.0.html)

Canon really did an excellent job creating the "raw data"->JPEG algorithms....

All is not lost though. The only long-term solution is to try to see what is going on inside the camera. The first steps have already been made:
http://chdk.setepontos.com/index.php/topic,2941.0.html
Gosh - each day I visit this one to see if there was any additional reply :)
---
The other approach I tried (and got a really nice result!) was to use the free Adobe DNG Profile Editor with Gretag Macbeth Color Checker. Yes, the Color Checker is a bit expensive... The only problem with this is that the camera profiling is much more difficult than monitor profiling. It requires TWO good sources of quality light (a small scale http://www.creativepro.com/article/the-darkroom-makes-a-comeback-part-2-).

The Color Checker is GREAT if you can photograph the target each time you make a picture. This is too cumbersome to be of any practical every-day use though.
Logged
*

Offline vit40

  • ****
  • 276
Re: Problems with color when importing a .dng into photoshop cs3
« Reply #34 on: 11 / February / 2009, 07:38:08 »
Yes ... what's interesting, this whole CHDK stuff started because of possibility to shoot raw. And many people are using raw, most of them get results with silly colors, because matrices for those cameras are off, but almost everybody is happy with it and almost nobody complains ...
Logged
*

Offline Howdy

  • *
  • 21
  • [S5 IS]
Re: Problems with color when importing a .dng into photoshop cs3
« Reply #35 on: 11 / February / 2009, 09:16:11 »
Well, maybe it is because the level of "silliness" differs with each camera? :) The CHDK produces acceptable results and most people are happy with it. The difference between "acceptable" and "stunning" is not that great too.

Also the CHDK is much more than "just" RAWs. We also have scripting, overriding, live histogram, hyperfocal calculator, battery indicator and a group of very knowledgeable people in this forum. For most people this is more important than the RAW support.
Logged
*

Offline Microfunguy

  • ****
  • 4037
    • StereoData Maker
Re: Problems with color when importing a .dng into photoshop cs3
« Reply #36 on: 11 / February / 2009, 09:23:59 »
Quote from: Howdy on 11 / February / 2009, 09:16:11
For most people this is more important than the RAW support.

Do you have any images that show RAW is worth the effort on CHDK cameras ?

If so, it would be useful to upload the original files so that we can 'play' with them.

The Canon 'fine' JPG's are normally good.


David
Logged
*

Offline vit40

  • ****
  • 276
Re: Problems with color when importing a .dng into photoshop cs3
« Reply #37 on: 11 / February / 2009, 09:43:26 »
Well, I'm shooting raw for several reasons - possibility to tune WB, exposure and noise reduction. Jpegs are generally good, but result from raw is better for me (of course, because of using well calibrated G9 matrix for A650, including Adobe color profile, which is quite good and very similar to Canon's and for some colors more natural). Of course, there are many other reasons for sticking with Canon and CHDK.

Logged
*

Offline Microfunguy

  • ****
  • 4037
    • StereoData Maker
Re: Problems with color when importing a .dng into photoshop cs3
« Reply #38 on: 11 / February / 2009, 09:51:52 »
Quote from: vit40 on 11 / February / 2009, 09:43:26
result from raw is better for me


Sure, but can you prove it  ?  :)

I accept the white-balance flexibility.

You have the RAW and the JPG, can you upload them somewhere so that we can play with the JPG ?
« Last Edit: 11 / February / 2009, 09:54:23 by Microfunguy »
Logged
*

Offline vit40

  • ****
  • 276
Re: Problems with color when importing a .dng into photoshop cs3
« Reply #39 on: 11 / February / 2009, 10:00:47 »
Well ... it's better for me, that's why I'm using raw, and I don't care if others would agree with me,
so I don't want to prove anything    :xmas
Logged
Pages: 1 2 3 [4] 5 6 7 8   Go Up
« previous next »
 

Related Topics


SimplePortal © 2008-2014, SimplePortal