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

A Colorimetric Analysis A Colorimetric Analysis Methodology forMethodology forPhilatelic StudiesPhilatelic Studies

Prepared for Stampshow 2010David L. Herendeen

12 August 2010

22

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

33

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

44

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

55

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

66

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 ??

88

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

99

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)

1010

BackgroundBackground

MeasureReflectance

orAbsorption

of Light

CIE Color Models

1111

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

1212

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

1313

Sampling the stampsSampling the stamps

…What we did

1414


…What we did

1515


…What we did

1616

Processing the resultsProcessing the results

…What we did

70 Sample Points - Ljubljana

0.480

0.485

0.490

0.495

0.500

0.505

0.510

0.310 0.320 0.330 0.340 0.350 0.360 0.370 0.380 0.390

u' (1976 CIE)

v' (

1976

CIE

)

1717

Processing the resultsProcessing the results

…What we did

1818

Comparison by expertComparison by expert

…What we did

1919

Color categoriesColor categories

…What we did


0.480

0.485

0.490

0.495

0.500

0.505

0.510

0.310 0.320 0.330 0.340 0.350 0.360 0.370 0.380 0.390

u' (1976 CIE)

v' (

1976

CIE

)

2020


…What we did


0.480

0.485

0.490

0.495

0.500

0.505

0.510

0.310 0.320 0.330 0.340 0.350 0.360 0.370 0.380 0.390

u' (1976 CIE)

v' (

1976

CIE

)

2121

Categories Defined by Color Expert

0.480

0.485

0.490

0.495

0.500

0.505

0.510

0.310 0.320 0.330 0.340 0.350 0.360 0.370 0.380 0.390

u' (1976 CIE)

v' (

1976

CIE

)


…What we did

Brick Red

2222


0.480

0.485

0.490

0.495

0.500

0.505

0.510

0.310 0.320 0.330 0.340 0.350 0.360 0.370 0.380 0.390

u' (1976 CIE)

v' (

1976

CIE

)


…What we did

Deep brownish carmine

Brick Red

2323


0.480

0.485

0.490

0.495

0.500

0.505

0.510

0.310 0.320 0.330 0.340 0.350 0.360 0.370 0.380 0.390

u' (1976 CIE)

v' (

1976

CIE

)


…What we did


RedBrick Red

2424


0.480

0.485

0.490

0.495

0.500

0.505

0.510

0.310 0.320 0.330 0.340 0.350 0.360 0.370 0.380 0.390

u' (1976 CIE)

v' (

1976

CIE

)


…What we did


Red

Carmine

Brick Red

2525

Categories are “Fuzzy”Categories are “Fuzzy”

…What we did

"Fuzzy" Color Categories

0.480

0.485

0.490

0.495

0.500

0.505

0.510

0.310 0.320 0.330 0.340 0.350 0.360 0.370 0.380 0.390

u' (1976 CIE)

v' (

1976

CIE

)

2626

Categories are “Fuzzy”Categories are “Fuzzy”

…What we did

Blow-up of Fuzzy Envelopes for Shades 2 and 3

0.490

0.492

0.494

0.496

0.498

0.500

0.502

0.504

0.506

0.508

0.510

0.320 0.325 0.330 0.335 0.340 0.345 0.350 0.355 0.360 0.365 0.370

u' (1976 CIE)

v' (

1976

CIE

)

1.00

0.84

0.40

0.17

0.14

Fuzzy WeightingFunction

2727

Theoretical Theoretical developmentdevelopment

…What we did

Formulated a method for defining Formulated a method for defining color categoriescolor categories

Created a model for understanding Created a model for understanding how individual perception can affect how individual perception can affect philatelic color identificationphilatelic color identification

Correlated this model to “real” test Correlated this model to “real” test datadata

Formed a building block for future Formed a building block for future philatelic color researchphilatelic color research

2828

Using a scannerUsing a scanner

…What we did

Spectroscope forTristimulus Values

(X,Y,Z)

CalibrateYour Scanner

(R,G,B)

Unknown Sample(Ru,Gu,Bu)

3D InterpolationFunction

Maps to:(Xu,Yu,Zu)

u’,v’Categories Defined by Color Expert

0.480

0.485

0.490

0.495

0.500

0.505

0.510

0.310 0.320 0.330 0.340 0.350 0.360 0.370 0.380 0.390

u' (1976 CIE)

v' (

1976

CIE

)

2929

What we learnedWhat we learned

How to apply the VSC 6000 for How to apply the VSC 6000 for colorimetrycolorimetry

Philatelic color is NOT a matching Philatelic color is NOT a matching problem, it is about categorizationproblem, it is about categorization

Colorimetry is faster and cheaper than Colorimetry is faster and cheaper than x-ray spectroscopy methodsx-ray spectroscopy methods

Scanners can be used to identify colors Scanners can be used to identify colors IF preliminary analysis has been IF preliminary analysis has been performedperformed

3030

What’s next?What’s next?

Completing the scanner Completing the scanner mappingmapping

Documenting and publishing Documenting and publishing all resultsall results

Extending the methodology to Extending the methodology to new projectsnew projects

3131

Two papers:Two papers:– Philatelic Shade Discrimination BasedPhilatelic Shade Discrimination Based

on Measured Color (Herendeen, Allen on Measured Color (Herendeen, Allen and Lera)and Lera)

Color Research and Applications Color Research and Applications and/orand/or London PhilatelistLondon Philatelist

– Using a Scanner to Determine Stamp Using a Scanner to Determine Stamp Shades (Herendeen, Allen and Lera)Shades (Herendeen, Allen and Lera)

London Philatelist London Philatelist oror Collectors Club Collectors Club PhilatelistPhilatelist

Documenting the workDocumenting the work

…What’s next?

3232

NPM SupportNPM Support

Value of NPM scholarship Value of NPM scholarship programprogram

Leveraging human resourcesLeveraging human resources Incubator for IAPIncubator for IAP

3333

AcknowledgementsAcknowledgements

Mr. Allen KaneMr. Allen Kane– For his vision of extending the services of For his vision of extending the services of

the NPM to the philatelic worldthe NPM to the philatelic world Mr. Thomas Lera, Winton Blount Chair Mr. Thomas Lera, Winton Blount Chair

of Research, NPMof Research, NPM– For his continual support and assistance For his continual support and assistance

with all aspects of this effortwith all aspects of this effort Mr. James Allen, Senior Fellow, IAPMr. James Allen, Senior Fellow, IAP

– For his long hours sorting and categorizing For his long hours sorting and categorizing Slovenian postage duesSlovenian postage dues

The EndThe End

Documents

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