A Colorimetric Analysis Methodology for Philatelic Studies Prepared for Stampshow 2010 David L. Herendeen 12 August 2010

How Many Colors? 1,2 or 3 200,010,010 200,020,10 There are 2!

How Many Colors? 1,2 or 3 There are 3! 230,250,090 230,235,90 220,240,085 There are 3!

How Many Colors? 1,2 or 3 200,010,010 200,020,010 There are 2!

What Color Are These 1851 Stamps ? Bright Orange Brown Rose Brown Intense Orange Brown Dull Red Dull Claret Pale Orange Brown Morocco Dull Red Rose Brown Reddish Orange Brown Deep Orange Brown Dull Claret Courtesy National Postal Museum

What Color Are These 1851 Stamps ? Bright Orange Brown Rose Brown Intense Orange Brown Dull Red Dull Claret Pale Orange Brown Morocco Dull Red Rose Brown Reddish Orange Brown Deep Orange Brown Dull Claret Courtesy National Postal Museum

Color is not so Easy IS IT ?? Is there Another Way?

Talking Points Some background What we planned What we did What we learned What’s next? NPM Support ...A Retrospective

Background What is color? What is colorimetry Spectroscopy and the VSC 6000 How are colors measured? Commission International de l’Eclairage (CIE)

Background CIE Color Models Measure Reflectance or Absorption of Light

What we planned Use the NPM VSC 6000 to perform colorimetric analysis Understand colorimetry in the philatelic context Understand the scientific measurement of color and its relationship to stamps Determine if scanning can be used as a cost-effective substitute for spectroscopy

What we did Analyzed hundreds of Slovenian postage due stamps of 1919-21 Recorded results and reduced data Correlated spectroscopic results with human color expert Developed interpolation model for use with scanners

…What we did Sampling the stamps

…What we did Sampling the stamps

…What we did Sampling the stamps

Processing the results …What we did Processing the results

Processing the results …What we did Processing the results

…What we did Comparison by expert

…What we did Color categories

…What we did Color categories

…What we did Color categories Brick Red

…What we did Color categories Deep brownish carmine Brick Red

…What we did Color categories Deep brownish carmine Brick Red Red

Color categories …What we did Deep brownish carmine Brick Red Red

Categories are “Fuzzy” …What we did Categories are “Fuzzy”

Categories are “Fuzzy” …What we did Categories are “Fuzzy” 1.00 0.84 0.40 0.17 0.14 Fuzzy Weighting Function

Theoretical development …What we did Theoretical development Formulated a method for defining color categories Created a model for understanding how individual perception can affect philatelic color identification Correlated this model to “real” test data Formed a building block for future philatelic color research

3D Interpolation Function …What we did Using a scanner Spectroscope for Tristimulus Values (X,Y,Z) Calibrate Your Scanner (R,G,B) 3D Interpolation Function Maps to: (Xu,Yu,Zu) u’,v’ Unknown Sample (Ru,Gu,Bu)

What we learned How to apply the VSC 6000 for colorimetry Philatelic color is NOT a matching problem, it is about categorization Colorimetry is faster and cheaper than x-ray spectroscopy methods Scanners can be used to identify colors IF preliminary analysis has been performed

What’s next? Completing the scanner mapping Documenting and publishing all results Extending the methodology to new projects

Documenting the work Two papers: …What’s next? Documenting the work Two papers: Philatelic Shade Discrimination Based on Measured Color (Herendeen, Allen and Lera) Color Research and Applications and/or London Philatelist Using a Scanner to Determine Stamp Shades (Herendeen, Allen and Lera) London Philatelist or Collectors Club Philatelist

NPM Support Value of NPM scholarship program Leveraging human resources Incubator for IAP

Acknowledgements Mr. Allen Kane For his vision of extending the services of the NPM to the philatelic world Mr. Thomas Lera, Winton Blount Chair of Research, NPM For his continual support and assistance with all aspects of this effort Mr. James Allen, Senior Fellow, IAP For his long hours sorting and categorizing Slovenian postage dues

The End