1. Camera scanning (negatives), spectral lighting testing, Dynamic range tests
  2. Spectral analysis of different light sources

Final spectrum analysis

Demonstrates new color rendering metrics in ArgyllPro ColorMeter 1.2. Duv and DeltaE measure the tint away from white. Television Lighting Consistency Index (EBU TLCI-2012) is newer than CRI (Color Rendering Index) and measures how a light source renders colors as viewed by a television camera (as opposed to human eyes.) This *may* be more meaningful for digital cameras than CRI is.

Starting off with a standard tungsten bulb and then natural daylight, we see that they measure pretty well. The various artificial light sources (CFLs and LEDs) are worse.

100 is perfect for both CRI95 and TLCI-2012; lower is worse. A "standard" tungsten bulb isn't quite lab standard. And daylight varies somewhat depending on what is in the sky (or is going on on the surface of the sun.) And the measuring instrument isn't perfect. But higher is better for CRI and TLCI.

Lower is better for Duv and Delta E. A high number for either indicates a tint: negative is pinkish; positive is greenish. 0 is pure white (as the eyes see.)

R9 is the saturated red patch of the extended CRI test. Low R9 numbers mean that the light source won't display reds very well.
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Cree TW 2700K LED (Manuf. claim is CRI 93)   (new version with no neodymium notch in the yellows)
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Cree TW 2700K LED (Manuf. claim is CRI 93) (new version with no neodymium notch in the yellows)

  • Standard 100 watt tungsten bulb (shows Duv)
  • Standard 100 watt tungsten bulb (shows Delta E)
  • Standard 100 watt tungsten bulb displayed on the 1931 chromaticity diagram.  The blackbody locus (curve in the center) is where "white" is. Lower Duv and Delta E2K numbers indicate better "whiteness"  Higher of either means a tint.
  • Standard 100 watt tungsten bulb.  Blow up of the black body locus so you can see how far the light sources is away from the locus.  Duv and Delta E are both measure of how far the light source is away from white.  Up (positive) means a green tint.  Down (negative) means a pink tint.
  • Real daylight.  Clear sky, approx. 30 minutes past noon.
  • Real daylight.  Clear sky, approx. 30 minutes past noon.
  • 12 V Solux 4700K
  • Solux PAR38 90 W 120V 3500K
  • Soraa 00807 5000K (manuf. rating of 95 CRI) LED.  I don't know why ColorMeter only gives it a CRI of 88.6.  Every other CFL or LED I've measured has met, or exceeded the manufacturer's CRI rating.   Except for this one.  Dunno.  The TLCI is pretty impressive, though.
  • Soraa 00807 5000K (manuf. rating of 95 CRI) LED
  • Soraa 00807 5000K (manuf. rating of 95 CRI) LED
  • Indoor Sunshine 5500K CFL
  • Philips 2700K CFL (Probably not too good for photography.)
  • Philips 2700K CFL (Probably not too good for photography.)
  • Cree TW (manuf. claim is CRI 93) 2700K LED (old version with neodymium notch in the yellows)
  • Cree TW 2700K LED (Manuf. claim is CRI 93)   (new version with no neodymium notch in the yellows)
  • Cree TW 2700K LED (Manuf. claim is CRI 93)   (new version with no neodymium notch in the yellows)
  • Cree TW 2700K LED (Manuf. claim is CRI 93)   (new version with no neodymium notch in the yellows)
  • GE Reveal "enhanced spectrum" 2700K LED<br />
The ColorMeter documentation says: "The values will be annotate with (Invalid) if the color is not within the standard tolerance of the illuminant locus."<br />
I have found this bulb to have an unacceptable pinkish tint.
  • GE Reveal "enhanced spectrum" 2700K LED<br />
The ColorMeter documentation says: "The values will be annotate with (Invalid) if the color is not within the standard tolerance of the illuminant locus."<br />
I have found this bulb to have an unacceptable pinkish tint.
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