Last call for color-target shots for inclusion in RawTherapee 5


#61

Haha, I’ve one too, in our oven. But it’s only a few Watts. It hardly lights up the Kuchen/Torten which I bake…:grin:


(Ingo Weyrich) #62

Iirc they are available up to 40 Watts.
Edit: Tungsten bulbs are still allowed for special applications. For example you can get shock resistant 200W tungsten bulbs


(Morgan Hardwood) #63

Just a heads-up that these bulbs are not suitable for profiling:

BAD BAD DO NOT USE


#64

Does a (or a pair of) standard tungsten General Electric 150w bulb(s) work, and does the glass coating matter? My local hardware shop had https://www.homedepot.com/p/GE-150-Watt-Incandescent-A21-Clear-Light-Bulb-150A-CL-TP12/100493791 clear ones, but also comes in a soft white bulb.


(Morgan Hardwood) #65

It matters that it’s clear, that it doesn’t filter the spectrum in any way.

The page you posted doesn’t mention tungsten, so it looks ok but I’m only guessing. What is the price? It’s not visible here, just says “unavailable”.

This is what we’re after:


#66

I paid less than US$5 apiece about a year ago, but it says unavailable here too now. I think they currently offer Sylvania https://www.homedepot.com/p/Sylvania-150-Watt-A21-Incandescent-Light-Bulb-10598/203117449 at less than US$3.


#67

I noticed our lamps are a different voltage. One of ours would blow up on 230V.


#68

If I’m not mistaken, halogen bulbs have a tungsten filament. Are such bulbs suitable?


(Morgan Hardwood) #69

@mikesan I don’t know… would be great to test, if the same person could shoot the same target using both a halogen and a typical recommended tungsten bulb.


#70

Quote:
Like all incandescent light bulbs, a halogen lamp produces a continuous spectrum of light, from near ultraviolet to deep into the infrared. Since the lamp filament can operate at a higher temperature than a non-halogen lamp, the spectrum is shifted toward blue, producing light with a higher effective color temperature and higher power efficiency.

Ref: https://en.wikipedia.org/wiki/Halogen_lamp

Have fun!
Claes in Lund, Sweden


#71

Ok, I found a tungsten 60W light bulb. I got an old light fitting, hassled some wires together and plugged it in. Et voila, colorchecker passport photographed:
NikonD800EStdA 1EV.NEF (42.0 MB)
NikonD800EStdA0EV.NEF (40.3 MB)
NikonD800EStdA-1EV.NEF (39.0 MB)

description for all 3 files:
Nikon D800E Colorchecker passport StdA testshot for RT DCP color profiling.
Shot in my man cave. :smiley:
Colorchecker passport is approx. 2 years old. Only used/exposed to daylight/tungsten <23 times.

I hope these images, and the previous (daylight) ones, are sufficient to create the required profiles. Correct?


#72

Two target shots PM’d to @Morgan_Hardwood,
one halogen, one old-fashioned bulb.

Have fun!
Claes in Lund, Sweden


(Morgan Hardwood) #73

Fantastic, thanks @PanoMeister and @Claes!


(Morgan Hardwood) #74

The D800E seems to have a wrong white point:


#75

??

How must I understand this statement?
Is there something wrong with the NEF files I uploaded?
Or is this something you derived from the files I uploaded?
Or does this mean that (previously) D800E NEF files were wrongly processed with RT?


(Morgan Hardwood) #76

It’s something I observed in your over-exposed shot, and it’s something we must improve in RT. Currently (and previously) clipped areas from the D800E have a magenta cast when it should be clipped-white.


(Morgan Hardwood) #77

NIKON D800/D800E dual-illuminant DCP added to RT.

The one in RT uses the “Neutral” tone reproduction operator and “AdobeRGB-Strong” gamut compression.

Neutral - By advanced perceptual modeling it keeps color appearance neutral/unchanged when contrast is changed.
ACR — the tone curve used by Adobe Camera Raw and defacto standard for DNG profiles, which is a curve that copies the saturation increase of the RGB curve, but keeps the HSV-hue constant so perceptual hue shift is (almost) eliminated.

Gamut compression
Purpose: select how much the saturation of ultra-saturated colors should be reduced to lower the amount of out-of-gamut clipping.
The gamut compressor is not “exact”, that is even if you set it to “sRGB” (the smallest gamut) it may produce colors outside of that gamut. The reason is that some clipping is desired otherwise scenes like sunsets will look flat and dull. The “Strong” variants applies a contrast compression in addition to a pure saturation compression, which further compresses the gamut.
How strong compression to use is a matter of taste, and it also depends on how well your raw converter can handle gamut compression in itself. The default setting works well in a variety of conditions and is about the same strength as found in typical bundled profiles. The gamut compression effect can be hard to see in “normal” images as it only affects high saturation colors — in other words you should use images with bright high saturation colors when comparing the effects of the various settings.

DCP variants to play with:
https://filebin.net/uutbgnpeemm8yzf6

Test images:
https://www.imaging-resource.com/PRODS/nikon-d800e/Y-Laowa105-JPG9191.NEF.HTM
https://www.imaging-resource.com/PRODS/nikon-d800e/Y-nikond800e-nikon28f14e-JPG9500.NEF.HTM
https://www.imaging-resource.com/PRODS/nikon-d800e/Y-nikond800e-nikon28f14e-JPG9590.NEF.HTM
https://www.imaging-resource.com/PRODS/nikon-d800e/Y-nikond800e-nikon28f14e-JPG9654.NEF.HTM
https://www.imaging-resource.com/PRODS/nikon-d800e/YBSG-135mm-2260.NEF.HTM
https://www.imaging-resource.com/PRODS/nikon-d800e/YBSG-135mm-2263.NEF.HTM


#78

@Morgan_Hardwood

May I assume these parameters are those selected when using DCamProf to create profile?

Next question: Regarding use of Enfuse: I use the GUI front end with that program. What options are used when processing the images?

I have observed this phenomenon when using Dcraw with the “wrong” arguments (i.e. the default saturation point which Dcraw uses for the camera in question). Thus I have believed the problem lies with the converter rather than with the camera.


(Morgan Hardwood) #79

@mikesan

  1. You can probably find the same parameters in DCamProf.
  2. Enfuse has no GUI of its own, there are only third-party GUIs. Regardless, this thread has nothing to do with Enfuse.
  3. The problem is the wrong white level in RT, though it’s odd because we already have detailed entries for that camera in our white-point database.

(ribin3d) #80

I have Lumix ZS100 if you need.
Also I had Canon EOS 6D. Where I can find link to color-target shots for it?