Author Topic: Green/Magenta tint in RAW's DNG  (Read 7550 times)

neofg

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Green/Magenta tint in RAW's DNG
« on: July 11, 2013, 02:02:01 PM »
Hi all.
When I open a Raw's DNG in Photoshop or After Effects, I found a strange "green/magenta" tint in the frame that I Can't fix with the standard "White Balance" tools.
Where I go wrong?

I post here an example.
This isn't from Canon, but the first Bolex tests from Bolex's site. Over is how look the DNG when I open it (Face is Magenta, background is green!!!). Down the .jpeg posted by Bolex on the site... (Perfect)...



You Can download the original dng at:

http://www.digitalbolex.com/wp-content/uploads/2013/07/BLX00001-20110317-0000436-15mm-Elitar.dng

tihon

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Re: Green/Magenta tint in RAW's DNG
« Reply #1 on: July 11, 2013, 09:44:22 PM »
+1

And what about resolve? Is it ok in davinchi?
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neofg

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Re: Green/Magenta tint in RAW's DNG
« Reply #2 on: July 15, 2013, 01:22:15 PM »
The same in DaVinci...
Any help?

mageye

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Re: Green/Magenta tint in RAW's DNG
« Reply #3 on: July 15, 2013, 01:51:17 PM »
What happens if you use a white balance reference card and use the 'White Balance Tool'? Do you have one? maybe you should try it and see what value you get?

Just an idea.
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IliasG

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Re: Green/Magenta tint in RAW's DNG
« Reply #4 on: July 15, 2013, 03:49:38 PM »
The same in DaVinci...
Any help?

Something goes wrong in the way the color matrix is written in exif.

If you use no color matrix (with Rawtherapee choose "no profile" at color management) and then you copy the color matrix 1 coefficients (multiplied by 100 so 1.89 becomes 189..) in RT's "channel mixer" you take the colors you describe as "perfect".

In case you have difficulty finding those multipiers here they are ..  as written in exif
1.80477 -0.54011 -0.26466 -0.19744 1.36156 -0.16413 0.21195 -0.83605 1.6241
and after X100 .... 180 -54 -26 -20 136 -16 21 -84 163.

We have to dig in DNG specs to find the correct writing of color matrices and correct it in exif data..

Edit. Looks like the multipliers are at the inverse order .. 163 -84 21 -16 136 -20 -26 -54 180.

premini

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Re: Green/Magenta tint in RAW's DNG
« Reply #5 on: July 17, 2013, 07:25:53 AM »
Same problem here, i detected it in resolve, it gets more evident after some color correction.

neofg

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Re: Green/Magenta tint in RAW's DNG
« Reply #6 on: July 17, 2013, 09:45:52 AM »
Something goes wrong in the way the color matrix is written in exif.

If you use no color matrix (with Rawtherapee choose "no profile" at color management) and then you copy the color matrix 1 coefficients (multiplied by 100 so 1.89 becomes 189..) in RT's "channel mixer" you take the colors you describe as "perfect".

In case you have difficulty finding those multipiers here they are ..  as written in exif
1.80477 -0.54011 -0.26466 -0.19744 1.36156 -0.16413 0.21195 -0.83605 1.6241
and after X100 .... 180 -54 -26 -20 136 -16 21 -84 163.

We have to dig in DNG specs to find the correct writing of color matrices and correct it in exif data..

Edit. Looks like the multipliers are at the inverse order .. 163 -84 21 -16 136 -20 -26 -54 180.

This could be the solution. Thanks.
I have this problem with all files and in all softwares, so it's my computer where all is written in the inverse order.
Because I have thousand of files, how Can I fix this in AE, or Da Vinci...

IliasG

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Re: Green/Magenta tint in RAW's DNG
« Reply #7 on: July 17, 2013, 12:09:36 PM »
I tried to do the conversion in exif data but I had limited success. While the colors seem more correct, the t-shirt turns from green tone to blue tone but the colors are very saturated. Something is missing from my method ...

If you can make a shot of colorchecker passport under sunlight then we can make a dcp profile and copy the color matrix in the exif data. You will need to batch convert the exifs of your files with exiftool - exiftoolgui.

If you cannot provide a colorchecker passport shot then we can ask from color experts to provide instructions .. I am thinking of color management category at Luminous Landscape forums ..

Doyle4

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Re: Green/Magenta tint in RAW's DNG
« Reply #8 on: July 17, 2013, 12:38:27 PM »
If its footage you cant re do and need to edit the files you have, maybe try in ACR turning down the green hue/luminance/saturation?

neofg

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Re: Green/Magenta tint in RAW's DNG
« Reply #9 on: July 19, 2013, 01:01:49 PM »
On forums answers sometimes go out...  ;)
I have this problem with ALL Dngs...
Try the original from Bolex site:

http://www.digitalbolex.com/wp-content/uploads/2013/07/BLX00001-20110317-0000436-15mm-Elitar.dng

What happen when you import in AE or DaVinci?

a1ex

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Re: Green/Magenta tint in RAW's DNG
« Reply #10 on: July 19, 2013, 01:15:18 PM »
In ufraw, without color matrix I get this:


and with color matrix:


(white balance on the white board, near the vertical reflection from top-left of the face)

IliasG

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Re: Green/Magenta tint in RAW's DNG
« Reply #11 on: July 19, 2013, 10:54:32 PM »
On forums answers sometimes go out...  ;)
I have this problem with ALL Dngs...
Try the original from Bolex site:

http://www.digitalbolex.com/wp-content/uploads/2013/07/BLX00001-20110317-0000436-15mm-Elitar.dng

What happen when you import in AE or DaVinci?

Once again, you need to make a custom profile, buy http://www.amazon.com/X-Rite-MSCCPP-ColorChecker-Passport/dp/B002NU5UW8
give it a shot under daylight and build your profile. Or upload the colorchecker shot if you need help ..

If the above is impossible you have to change the colormatrix in exif. As it is now seems it's in a wrong format for DNG specs but works OK as camera to sRGB conversion. Unfortunately I don't know how to translate it to DNG format ..

This is how it looks in RT after copying the colomatrix multipliers in channel mixer ..

IliasG

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Re: Green/Magenta tint in RAW's DNG
« Reply #12 on: July 20, 2013, 06:41:06 PM »
@ neofg,

give a try at the modified DNGs where I just changed the colormatrix with the one from Pentax645, it's closer to what you want, please try and report if it's close enough.

http://rapidshare.com/files/2796423499/BLX00001-20110317-0000436-15mm-Elitar%20-%20Pentax645.dng
http://rapidshare.com/files/3303040773/BLX00001-20110317-0000436-15mm-Elitar%20-%20Pentax645_dual_illuminant.dng