Colour issues :(

Hey just a quick question.
Am I crazy or are these colours off? The shadows (the path) shouldn’t be this magenta should it? I mean it’s a vintage lens but like WHAT? :expressionless:
Sony A7-II with lens Vivitar Auto Macro 55mm f2.8 https://www.theweekendlens.com/vivitar-55-f28-macro.html

RawTherapee 5.8-398-g1beb3c9

S7_05276.ARW (47.6 MB)

Morning @stefan.chirila,

Er… A swift guess: might you have been developing it
in latest RawTherapee :slight_smile:

For me it looks okay, when increasing the color temperature to ~4300K. Done in darktable.

The camera ‘tint’ value is a bit too low for this scene I think. With RT setting WB to 4300 and tint to 0.8 gives practically the same result as @Thomas_Do

Acctually, I believe that something has snapped in RawTherapee – I started to notice it a day or two ago.

ART 1.3-112-g4f808861e develops Stefan’s img nicely.
RT 5.8-447-g1fe03b298 creates a heavy cast

@Claes Could it be 5749?

I agree with the WB comments, the values do seem a bit extreme considering the scene. Looks ok with stock color profile, default WB and minor color shift

S7_05276.jpg.out.pp3 (12.1 KB)

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Moinchen @floessie!
It could very well be the same culprit.

I don’t think the GCC10 bug is the issue here. On my machine with RT5.8 latest dev compiled with GCC9.3 the image (with only +1 EV exposure added), looks like this:

But when the WB is set to 4250 en tint 0.85 you get this, which I think is very acceptable:

yes, appimage from the repository RawTherapee 5.8-398-g1beb3c9

No offense but I just don’t think the earth should be this blue, nor the tree. :frowning:

To try to pinpoint the culprit, I just opened an image which I have not touched for over a year. The heavy cast seems to appear irrespective of kind of RAW file. In this case, they are RW2. Problem also appears for .RAF, as well as for Stefan’s .ARW.

Have fun!
Claes in Lund, Sweden

Interesting, I checked the image in the GIMP and the color of the track is quite neutral (maybe a little short in red). But in my example above, the earth off the track is really neutral.

However, when I look at @Claes screenshot, the color cast looks realy ugly to me but more red than blue.

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That’s the gcc 10 issue for sure.

There is a lot of color fringing and noise messing up the colors in the image, see the lower part in the screenshot at 200% below:
Bildschirmfoto_2020-06-04_19-04-28

The image was taken with 1/500 seconds exposure and ISO 1600, using a higher exposure time and lower ISO should give you a better result

It’s a tough image because you’re dealing with sunlight, shade, sunlight filtered through green leaves, and infrared (or far red, rather) contamination caused by the IR radiating from all the foliage. It’s the IR contamination that causes greenery to look sort of yellow and the muddy red/magenta cast in the path.

I wouldn’t expect modern cameras to be very IR sensitive. Most people who want to do IR photography buy older dSLRs. But hey what do I know.

Yeah, cameras have built in IR filters that block pretty much all IR contamination in normal conditions, but in situations where visible light is blocked or filtered out but IR light is passed freely then the proportion of IR to visible is raised to the point where it can cause muddy colors. I.E., the tree canopy filters visible light so you increase exposure, but IR isn’t filtered out by the trees and so you end up with more IR exposure than you normally would. The same thing can happen with neutral density filters. Traditional ND filters block visible light, but freely pass IR. So when you increase exposure to compensate for the ND you dramatically increase IR.

Here’s an extreme example showing a normal shot, a shot with a dense traditional ND filter, and a shot with an IR blocking ND filter. Video cameras are usually more susceptible than still cameras, but it still happens, just not as bad as this usually.

Just fetched RawTherapee 5.8-448-g49c4d0a27, and
yesterday’s heavy cast has now disappeared.
Thank you, devs!

Did this new version fix your dilemma, too, @stefan.chirila?

Claes in Lund, Sweden

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