A Colorimetric Analysis A Colorimetric Analysis Methodology forMethodology forPhilatelic StudiesPhilatelic Studies

Prepared for Stampshow 2010David L. Herendeen

12 August 2010

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200,010,010 200,020,10 200,010,010

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230,250,090 230,235,90 220,240,085

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200,010,010 200,010,010 200,020,010

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What Color Are These 1851 Stamps ?

Bright Orange BrownRose Brown

Intense Orange Brown

Dull RedDull Claret

Pale Orange Brown

MoroccoDull Red

Rose Brown

Reddish Orange Brown

Deep Orange BrownDull Claret

Courtesy National Postal Museum

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What Color Are These 1851 Stamps ?

Bright Orange BrownRose Brown

Intense Orange Brown

Dull RedDull Claret

Pale Orange Brown

MoroccoDull Red

Rose Brown

Reddish Orange Brown

Deep Orange BrownDull Claret

Courtesy National Postal Museum

Color is not so EasyColor is not so Easy

IS IT ??IS IT ??

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Talking PointsTalking Points

Some backgroundSome background What we plannedWhat we planned What we didWhat we did What we learnedWhat we learned What’s next?What’s next? NPM Support NPM Support

...A Retrospective...A Retrospective

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BackgroundBackground

What is color?What is color? What is colorimetryWhat is colorimetry Spectroscopy and the VSC Spectroscopy and the VSC

60006000 How are colors measured?How are colors measured? Commission International Commission International

de l’Eclairage (CIE)de l’Eclairage (CIE)

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BackgroundBackground

MeasureReflectance

orAbsorption

of Light

CIE Color Models

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What we plannedWhat we planned

Use the NPM VSC 6000 to perform Use the NPM VSC 6000 to perform colorimetric analysiscolorimetric analysis

Understand colorimetry in the philatelic Understand colorimetry in the philatelic contextcontext

Understand the scientific measurement Understand the scientific measurement of color and its relationship to stampsof color and its relationship to stamps

Determine if scanning can be used as a Determine if scanning can be used as a cost-effective substitute for cost-effective substitute for spectroscopyspectroscopy

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What we didWhat we did

Analyzed hundreds of Slovenian Analyzed hundreds of Slovenian postage due stamps of 1919-21postage due stamps of 1919-21

Recorded results and reduced dataRecorded results and reduced data Correlated spectroscopic results Correlated spectroscopic results

with human color expertwith human color expert Developed interpolation model for Developed interpolation model for

use with scannersuse with scanners

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Sampling the stampsSampling the stamps

…What we did

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Sampling the stampsSampling the stamps

…What we did

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Sampling the stampsSampling the stamps

…What we did