Sony ARW looks yellow in RT

Software RawTherapee
36

Um, I could have sworn his EXIF said it was a 6500, not a 6000… Where are you getting a 6000 from?

I’ll need to check again when I get home. Maybe I ran exiftool against the wrong file. OP has never explicitly stated what camera he’s using, but didn’t disagree with me when I said A6500…

If somehow something is assigning A6000 color matrices or profiles to A6500 color matrices, somehting is likely to go very wrong, because the A6300 introduced an entirely new sensor. A6300,6500,6400,6100,6600 in theory use the same sensor but MIGHT have different CFAs.

(why that oddball ordering? That’s chronological order of release of the bodies in question.)

Edit: Wait, the two examples the OP provided are coming from two completely different cameras??? One is from an A6000, one from A6500.

37

In rawproc, the mantis raw camera model shows 6000… source: Libraw.

38

Yes the mantis is from a 6000 and the room from a 6500 (source exiftool)

39

Would have been nice if the OP had mentioned these are examples from two different cameras.

For the indoor shot, artificial lighting combined with a single-illuminant color matrix might be a contributor. For the outdoor mantis A6000 shot - not sure.

(RT has a dual-illuminant profile for the A6000, but for A6500 just has the basic color matrix)

40

Yes, the two images are from different cameras. The mantis was shot on my a6000 and the room was shot as a test with my a6500. However, RT has a profile for both the a6000 and the a6500 and the yellow cast is the same in images from either camera.

I have managed to get close to what I would call accurate color rendition using the neutral profile and with some manipulation of the color temperature sliders and/or the green sliders in the RAW tab but nothing so far has been what I would call “spot on”. The same files processed with CaptureOne with NO color manipulation always look much closer to “remembered reality”. Whatever the issue is, it does not seem to be a simple RGB levels issue because that would be easily addressed with the channel mixers? It “feels” more like a gamma or curve issue with one or more individual colors.

I have been playing A LOT with RT on many images and every time I think I’ve got the color to what I would call acceptable I flip over and view the image in CaptureOne and find I’m not there yet. The yellow bias is still there in varying amounts.

BTW, I have found that the auto levels control is indeed working as intended. By enabling the over/under warnings, I find that there ARE outlier pixels at each end of the range (more than I expected) that cause the levels to seem to be compressed.

Yes, the lighting in both examples is not simple. There is a small amount of daylight in the high ISO room image and the light in the mantis shot is likely affected by reflections from all the vegetation. However, it did not seem to materially affect the image in the camera viewfinder or what CaptureOne shows. So I’m not sure it is the culprit here.

Paul

41

RT does NOT have a dual-illuminant profile for both A6000 and A6500 - only A6000:

For A6500, there is only the basic DNG color matrix.

Note that in another discussion somewhere, there was evidence that C1 is doing some really weird things with colors in their profiles:

I own an A6300 and A6500, so now that things are calming down, I MIGHT be able to submit to @Morgan_Hardwood the ColorChecker shots needed to generate DCP profiles for those cameras.

MIGHT being that around here, “cloudless noon sunlight” is extremely rare in winter. We’re under a winter weather advisory so I don’t expect to see unobstructed sunlight for a few days. On the other hand, I have two days of work remaining before I hit “use it or lose it” for my vacation days, so I’ll have much more lunchtime availability for camera profiling if the sun ever comes out. :slight_smile:

3 Likes
42

@Entropy512 the difference between a target shot properly on an overcast winter midday vs shot on a cloudless summer midday is greatly smaller than the difference between a properly shot target under any daylight vs no DCP at all, so go ahead and shoot - we can always submit a better one if summer ever comes around again.

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I just finished shoveling snow off my driveway for the fourth time this season. I’m not betting on it… :snowman_with_snow:

44

My oh my, that thread was an interesting read. I guess I now understand better why I have been unable to duplicate my C1 results in RT. I always felt there was something non-linear going on and that it wasn’t simply RGB values.

Paul

1 Like
45

I felt something like that was going on, shoulda wrote this sooner:

Most FOSS software comes with a giant collection of “camera primaries”, sets of nine (or more, for cameras with weird color spaces) numbers that describe the extent of their spectral response. Those nine numbers can be thought of as a “reddest red”, “greenest green”, and “bluest blue” of the camera’s sensor. Actually, a lot of these primary sets come from the collection of profiles Adobe releases with their DNG Converter; a lot of others, for older cameras, come from dcraw.c, a command-line raw processor that is kind of a reference implementation for a raw processor. When a new camera comes out, the lag in support by raw processors, commercial and FOSS, is the inclusion of these nine numbers for that camera. There can be other numbers supporting the camera, but these are what I’ll call “first-order essential”.

In the path to an output image file, the camera colors need to be mapped to an appropriate colorspace, as the camera space is too big for most media. sRGB, AdobeRGB, etc, have their own set of primaries, nine numbers that describe their color gamut in the same terms as the camera primaries. The conversion is essentially a mapping of the pixel colors from camera space down to the output space of your choosing. There are different options for specifying this conversion; the predominant one simply leaves “low intensity” colors alone, as they occupy both spaces, and saves the heavy lifting of figuring out where to put colors from camera space that are outside the output space. This option is called “relative colorimetric”; there are three others in the ICC profile realm.

The reason I’m describing this bit of arcanery is that, linear camera matrix profiles, as the profiles containing the nine numbers (a 3x3 matrix) are called, typically “don’t lie” about the camera’s spectral response. They don’t contain non-linear curves or discontinuous LUTs that make the tones or colors look different. I’m abstracting this a bit, but I think of linear matrix camera profiles as the base characterization of the camera; anything else is a “look” or adaptation for some purpose. For instance, one can scooch the blue primary around to accommodate extreme blues, from certain theatrical LED lights for example, but in doing so one messes with all the other colors too.

So, I’d surmise you’ve been looking at a pleasing “look” in C1 renditions, and now you’re somewhat taken aback by the truth of your camera… Now, take the red pill… :smile:

3 Likes
46

Thanks for that, it was educational. I don’t fully understand all the nuances of color space but I’m working on it.

So what does a fella do in RT if he… likes that “pleasing look” in C1? Other than stay with C1, of course :wink: The color just looks more smooth, rich and natural to me than anything I have been able to produce in RT.

FWIW, I have now also tried ACDSee and Darktable. ACDSee seemed to come closer. Darktable did not. And neither had acceptable de-noising or ergonomics. I tried Lightroom a while back and I don’t recall any issues with color but I refuse to commit to raw development software that stops working if I ever stop paying.

Paul

47

Ah, I was surprised that the difference between dismal grey and blue sky would be that little… I can see “minor clouds” being a minor effect, but I would have thought that if it’s Ithacating you’re hosed.

Hopefully the parking lot will be clear enough to not gunk up my colorchecker if I try to shoot it Thursday. Today is just a horrible mess of slush all over.

48

If C1 is using a DCP profile for your camera, just drag it over to RT, see if that scratches the itch.

Me, having taken the Red Pill, I’d treat the C1 look as a “look”, akin to film emulations, and see if there’s a LUT to be had or constructed. I’m not specifically familiar with that hobby, but there are folks here who are. RT/dt/both (not sure which/both) have the capability to apply LUTs to images.

WRT camera profiling, I cut my teeth with @Elle Stone’s articles:

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These dialogues (diatribes?? :smile:) sometimes compel me to go look…

http://rawpedia.rawtherapee.com/Film_Simulation#Make_Your_Own

The above points to the specific itch scratcher, but you need to read the whole Film Simulation page to learn about HaldCLUTs…

50

Hi,

Here are my two cents. I used the ART fork of RT, which has a slightly different processing pipeline, but here’s what I could get. I basically only used the tone curve and camera-specific DCP profiles that I generated with dcamprof using the color targets in the dpreview studio scene tool (plus sharpening and noise reduction to match what you did with C1). If anything, it’s the C1 renderings that look a bit yellow to me…

DSC04493
DSC044931920×1282 1.41 MB

DSC04493.ARW.arp (9.5 KB)

DSC04425
DSC044251920×1282 699 KB

DSC04425.ARW.arp (9.6 KB)

6 Likes
51

Interesting. The room image looks great! The mantis image, not so much. To my eyes it is too cold / green.

Do I need to generate my own DCP files or would yours work for my a6000 / a6500? I looked and C1 does not seem to use DCP files so I can’t borrow them. Creating my own looks to be a serious effort in learning and execution :wink:

And pardon my ignorance, but what is an ARP file extension?

I would also like to thank EVERYONE who has participated so far. This has been most interesting and educational.

Paul

1 Like
52

sure, it’s definitely less yellow than c1. my point was that I don’t think there’s anything preventing you to get less yellow results with arw files from RT…

53

Well, it is certainly less yellow than the original or C1 but it doesn’t look natural or anything like it did in the viewfinder either. It was a warm sunny day and this version looks very cold. Maybe it is just a subjective thing, But I like what I can get from that RAW easily from C1. I don’t like what I can do in RT, even with a lot of effort. I can get close, just not all the way.

Your result on the room image, however, was very acceptable and better than I have ever gotten with that image in RT.

Are we kinda reaching the end of the road here? C1 is doing something to my images that RT is not, and no amount of conventional manipulation in RT can duplicate it. It is what it is? I learned a lot in the process and I know better where to look for further improvement.

Paul

54

Hi,

I think you are still missing the point I was trying to make, i.e. that there’s nothing in RT that makes it render files with a yellow cast.

If you want a slight yellow cast, there are many ways to do it. Here’s one (again, using ART, but with RT it wouldn’t be much different):

DSC04425-1
DSC04425-11920×1282 666 KB

DSC04425.ARW.arp (10.0 KB)

And here’s a composite of the two: one half is your C1 rendering, one half is my ART one. They are certainly not identical, but are acceptably close for me. Clearly, you might disagree:

c1-vs-art
c1-vs-art1920×1280 709 KB

1 Like
55

I see your point. However, as I understand it there is a lot of processing required to get a usable image from the raw sensor data and my assumption is that C1 and RT do it differently. Again, I am seeing a fundamental difference in the color rendering of the same file in C1 and RT without any user-applied color manipulation. So you are saying that what I like about the color rendering of C1 may just be a happy accident and not to expect it from RT because that is not how the file looks? I’ll have to think on that one. You may be right. But is there one and only one “correct and accurate” way to translate raw sensor data into a usable “starting point” image?

One thing I did discover today is that the color in the mantis image in RT changes (for the better) if I add some haze removal. That was quite a surprise and I’m not sure why that would be. Without haze removal, the mantis image looks cold and nothing like it does in C1 and I am unable to duplicate my C1 results. But if I add a moderate amount of haze removal, the image warms up and comes very close to how it appears in C1. I would even call the image “acceptable”. Note that I do have a small amount of “clarity” added in C1 by default which I think is doing something similar to RT’s haze removal. However, removing or modifying the “clarity” in C1 does not affect the color at all.

Haze removal does not seem to have much (if any) effect on the color in the high ISO room image, though. Not sure why it makes a difference in the mantis image and not the room image.

Paul