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Problems with color when importing a .dng into photoshop cs3

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bugmenot

Re: Problems with color when importing a .dng into photoshop cs3
« Reply #50 on: 23 / February / 2009, 14:16:42 »
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yes, i noticed that too. why this difference between day raw and night raw?

Re: Problems with color when importing a .dng into photoshop cs3
« Reply #51 on: 23 / February / 2009, 14:48:41 »
Don't know, I have found that darker (night, low light) photos are with very big oversaturation, -30 in photoshop RAW editor brings all back to normal, almost...
Also, play with photoshop Hue/Saturation tool and set Magenta color to saturation -100 to bring back black shadows.
This is the ONLY problem for me, blue/magenta shadows in low light shots. I don't understand of color profiles and codes, so please someone try to fix this.  :-[
A590IS user

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bugmenot

Re: Problems with color when importing a .dng into photoshop cs3
« Reply #52 on: 23 / February / 2009, 15:20:23 »
you can find inconsistences like this between raw and jpgs when you shoot at high ISO. At iso 800 the raw color was way off compared to the jpg.

Dunno what to say...maybe i am a bit unfair as i use Vivid on my jpgs.

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Offline zosX

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Re: Problems with color when importing a .dng into photoshop cs3
« Reply #53 on: 07 / March / 2009, 20:41:30 »
Interesting. I didn't think about it being oversaturated. Been playing with lightroom and the colors are skewed the same there too. I'm trying to come up with a reliable way to color correct the matrix. How are the values calculated in the first place? I mean who originally came up with the color matrixes that are used in chdk?


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Offline zosX

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Re: Problems with color when importing a .dng into photoshop cs3
« Reply #54 on: 07 / March / 2009, 23:35:14 »
0.647821 -0.158121 -0.110623 -0.119231 0.561393 0.042379 0.006041 0.079001 0.193900

Could anyone using a 590IS try the above color matrix. I created it with the calibrate tool in dng4ps2 and it appears very accurate. My shots in photoshop now look much much better once you get the white balance down. I could post some test shots as well as the color chart shots and the resulting converted color chart if you like.

BTW, the color matrix was created with 10 zones that all got less than 5% error rate in the end. I can't remember if 10 or 15 zones was the standard for good matrixes but just using 10 here gave pretty good results.
« Last Edit: 07 / March / 2009, 23:37:47 by zosX »

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Offline zosX

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Re: Problems with color when importing a .dng into photoshop cs3
« Reply #55 on: 08 / March / 2009, 00:07:36 »
oh...they say you need 22 zones....whoops...that matrix still isn't half bad. :)

after some experimenting with the calibration tool, it appears that if you select a good mix of red green and blue squares you can get it to calibrate pretty close if you pick the right squares. i guess your mileage may vary, but can some people confirm that this is an ok matrix because I believe it to be better than the one in the current firmware....
« Last Edit: 08 / March / 2009, 00:23:26 by zosX »

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Offline zosX

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Re: Problems with color when importing a .dng into photoshop cs3
« Reply #56 on: 08 / March / 2009, 11:56:56 »
As a side note, I found it extremely interesting to see how exactly green a RAW file from a CCD is. When I first looked at the raw that was not color corrected I immediately thought something was horribly wrong until I remembered that CCDs have a tendency to shift so far to the green, then it dawned on me that is precisely why the yellows and greens have a tendency to be so hard to pin down. I print things for a living, so matching color is important in my line of work. When I set the zones I thought would have the best chance of matching without error and looked at the rest of the zones they were all within 5% levels and considering that the jpeg colors won't ever really match the raw, I'll say that's close enough for me. I'm using the A590-101B build. I don't know if different revisions of the camera's firmware change anything on the CCD or not. So maybe the above matrix only applies to my set of cameras. There also does seem to be some funny things that happen when you take pictures in low light. I took a series of test shots and the darkest (-2/3 EV) was the one that it matched correctly. I would just suggest everyone calibrate to their own camera and find results that they are happy with, because I feel that everyone's mileage may vary. Now, what does one have to do to add custom matrixes to the custom firmware? I could try building under cygwin, but I'm not real confident that would work. If someone built me the latest release with that matrix above so I could experiment with it a bit, I would be much appreciated. zosxavius[-at-]gmail :)

thanks everyone for your help so far!

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Offline whim

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Re: Problems with color when importing a .dng into photoshop cs3
« Reply #57 on: 08 / March / 2009, 12:21:54 »
@zosX

done, check your mail  :D

wim


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Offline zosX

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Re: Problems with color when importing a .dng into photoshop cs3
« Reply #58 on: 08 / March / 2009, 12:23:45 »
Here was the steps that I took to get calibration shots. Remember that the accuracy of color in your monitor matters not because you are only calibrating the color to the jpeg, not the actual image. It should be noted that this makes the color only as accurate as the jpeg's rendition of color, which is not the same. The jpeg is sampled at 8-bits per sample versus the raw's 10-bits per sample, thus you will never get true precision. I am not an expert, and if any of this is wrong I apologize, so here goes. This is how I calibrated with dng4ps2.
I have a fairly large 19" CRT. It helps to take a good picture of something large. A good color chart would actually even be better. Here are the steps.

1. CLEAN MONITOR!!!!!

2. Get a color chart from this thread: http://chdk.setepontos.com/index.php/topic,390.0.html

3. Open color chart with your favorite image viewer and make the edges of it touch the edges of your screen so you get max size

4. Turn on your camera (this is the for dummies version) and set to manual mode. Make sure ISO is at its lowest value. Very important! Set zoom about halfway. (We'll get to that in a minute) Now set the manual focus to infinity. Set aperture to its lowest stop and find an exposure that is roughly -2/3 EV. Make sure that you are shooting in CRW and not DNG...this is very important. (I forgot myself)

5. Compose the shot so that hopefully there is some blur. With the zoom at halfway and the focus at infinity, the monitor should be close enough to be out of the focal range. If not, experiment until the maybe some text at the top of the monitor or whatnot appears about 50% blurred. This will help you I promise as the colors will tend to blend more in the resulting image. On a real color chart this may not be as necessary. Also make sure that the camera is not set to vivid color. Also set the white balance to sunlight.

5. Shoot a few exposures at different EV values. It helps GREATLY to do this at night in a completely dark room with only the monitor. In fact, it may be necessary.

6. Open DNG4PS2 and open up the profile for your camera. Hit the calibrate button.

7. Now you are presented with a window. Open the CRW that is the -2/3 EV. That should be your basis and is the exposure that I used. Now start drawing rectangles around the brightest squares. For reference look only at the RAW at first. It should be pretty dark. Try to get a good mix of the brightest red, green, and blue squares. I found that 10 worked for me, but your mileage may vary. Don't adjust the brightness unless nothing works for you. I find that playing with it skews the results because the lightness is different. I didn't touch it and it worked fine.

8. Hit the calibrate button and it will calculate. You want the error rate to be less than 10% and ideally closer to 5% in all your zones. If this fails delete problematic zones and try again. Then add different zones and keep trying. Eventually (HOPEFULLY!) your resulting image and the jpeg will start looking a lot closer. Sooner or later (with much playing around) you might get them to match. How close you can get it is a matter of personal taste I guess.

9. When the calculation goes well and you are satisfied you are given a matrix. Hit the save button or whatever and it will copy that line back to the profile preferences for dng4ps2. Now you can cut and paste and run setcolormatrix against all your existing dngs and compare.

That's it for me, if anyone has any questions please feel free to ask away.

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Offline zosX

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Re: Problems with color when importing a .dng into photoshop cs3
« Reply #59 on: 08 / March / 2009, 13:16:51 »
I do have one further question though. What is the purpose of two color matrices? Does the resulting dng somehow save different matrices for different lighting conditions?

 

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