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RED-Problem EASY

Guest .

Hi All,

you might rfemember
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thread on an issue which is well known to the SIGMA-community?!

Coincidently, I discovered a redicolously EASY way of overcoming any RED-Problems with such problematic RAW-files ... let's have a closer look:

Our RED-Problem ... we love it ... we hate it ....

Sample 8.JPG

As we know and as the histogramm clearly tells us. The RED-channel is obviously overdriven. Nobody really knows, why SIGMA's REd channel is that sensitive .... more sensitive than either green or blue-channels. The result is a large scale overdriven RED areas in the picture, that look like an ugly soup without any structures or details within. with the red channel fully driven, blue and green gain the upper hand and colours clip towards kindn of purple ... just watch it with my screenshot ... that is not, what garish red roses are supposed to look like!!

Solution is very very easy at hands! ;)

1) Just reduce colour Saturation within SPP to an extend that the red-channel comes under control ... watch the histogram! As you see ... colours are running flat now but structures become visible ... the roses become more and more plastic! Save your image this way!!

Sample 9.JPG

2) Just amplify colour saturation know with any suitable other picture-processing software! Now your roses regain their bright and lively colours ... your picture becomes brilliant and develops our beloved SIGMA 3D-look ... does it not?!

Sample 7.JPG

3) DONE!

Sample 10.jpg

Do not ask me why it works ....I do not know .... but it perfectly works! Just try yourself! ;)

See you with nice SIGMA REDs



Active Member
Whoa! That IS simple. I'm trying this when I get home, because I've got some seriously burned-out flowers. :)


Well-Known Member


Sigma should employ you to solve all their various colur issues!
Well done, Klaus.

Now we only miss a way to effectivly get rid of the green-magenta noise in underexposed parts of the picture.

kind regards


Active Member
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I've noticed that this happends only in some situations and on some red nouances or wavelengths (like roses) so maybe because of the silicon's gradual light absorbtion - red is the last and, perhaps less sensitive - and Sigma tried to force more gain in red, resulting clipping in those wavelenghts.
What do you say?

On topic: Nice done Klaus! It really works!


Active Member
Ok, I test this new easy method.

Here is the original.

Now, I desaturate just enough (not too much) to reveal washed out details and so the red in the histogram is no longer touching the right limit.

I save this file as JPEG. Then I open it SPP!

Resaturate. I noticed the histogram would not push the red back to the right limit, which is good.

The result.

All done in SPP. No other software. What do you think?


Well-Known Member
I suggest that you avoid saving the intermediate de-saturated file as a JPG.

The ADCs in the SD14 are 12 bits, and you loose the details in the lower 4 bits when you save to JPG (8 bits per channel), plus the JPG format itself is lossy, compressing the image more at the expense of color details.


Well-Known Member
Your fame is spreading ...

Courtesy of Øyvind, your fame is spreading on DPReview Sigma forum, Klaus. Can I have your autograph, please? :)

Sincere regards, JR

All are very welcome to visit my humble gallery @
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New Member

Thank you for posting this double tip - it is well worth the cost of my donation! I'm about to "pull the trigger" on purchasing studio darkroom though the one I've seen is the US version not the German version - will this noise reduction process still work?


Well-Known Member
Hi, CHEBB ...

Klaus mentions in one of his posts that the German version is the only version with that noise reduction feature. Sorry to spoil your day.

Sincere regards, JR

All are welcome to visit my humble gallery @
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Guest .

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Hi The Chebb,

Noise Reduction ... both ... colour noise and luminance noise ... is the same with the German and the English Version (RAW-Photo Studio vs. Arcsoft Darkroom). The difference is, that the German Version provides Selective Colour Control in addition.

See you with nice pictures



New Member
I tried this method, it works with only Raw Photo Studio, and it does not work if purple clipped -- they will become red after the treatment:)

I also noticed in the Klaus' post, the leaf of the flower has changed color after treatment.


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Hi Klaus, did you process from RAW to TIFF using DPP then open and process the TIFF in RPS? I have been looking for something to remove the low frequency noise at 1600ASA, have you had a look at my RAW files on the 'Processing Challenge' post? Image 24 was shot at 800ASA and has some LF noise on it.

Keep up the good work, Martin