1.22 Chromaticity Diagram


The Chromaticity Diagram app can be used to:

  1. Open a workbook template with CIE 1931 color space chromaticity diagram and CIE 1976 UCS (uniform chromaticity scale) diagram.
  2. Calculate CIE XYZ from photoluminescence spectra and add PL data to the chromaticity diagram.
  3. Plot L*a*b* data in 2D, 3D and convert L*a*b* data to CIE 1931 xyY.
  4. Convert XYZ to L*a*b*, XYZ to RGB and xyY to XYZ.


Download the Chromaticity_Diagram_Sample.zip file.

Open Chromaticity Diagram Template to add data

  1. Select the Chromaticity Diagram icon Chromaticity Diagram icon.png in the apps gallery window. Click the first button Open CD Template button.png of this app toolbar., and it will open a workbook template.
  2. Go to Chromaticity sheet. Two graph templates (CIE 1931 and CIE 1976) are inserted. The boundary of the chromaticity can be found in the Boundary worksheet. Column A, B and C are boundary data for CIE 1931 and column A, D and E are boundary data for CIE 1976.
    Chromaticity Diagram Template 01.png
  3. Double click on the worksheet cell, you can open the graph window . If you want to show color temperature in CIE 1931, click Show/Hide Color Temperature button on the bottom right of the graph. You can also add your own data to the graph template.
    Chromaticity Diagram Template 02.png
  4. To know the distribution in the chromaticity diagram, you can import Data.dat (in the download file) into Origin, and then drag and drop the data directly into the template.
    Chromaticity Diagram Template 03.png
  5. Double click the graph to open the Plot Details dialog, change the Plot Type from Line to Scatter. And change the symbol type. Click OK.
    Chromaticity Diagram Template 04.png
  6. Double click the axis which will open the Axis dialog. Select Both Horizontal and Vertical, and select Normal under Rescale drop-down list in the Rescale tab. Click OK.
    Chromaticity Diagram Template 05.png
  7. Now select the Scale In icon Scale In button.png and drag the area of interest to zoom in.
    Chromaticity Diagram Template 06.png
  8. Select the back arrow icon which will add the embedded graph back into the Chromaticity worksheet.
    Chromaticity Diagram Template 07.png

Chromaticity Diagram with PL

If you have photoluminescence spectral data and want to know its color in terms of the standard observer.

  1. Open Chromaticity_Diagram_sample.opju project (in the download file), select the Book1 in the Folder1 and highlight all columns.
    Chromaticity Diagram PL 01.png
  2. Select the PL button PL button.png to open the dialog. Confirm the dialog setting as below image:
    Chromaticity Diagram PL 02.png

    Then click OK. You will get the each PL spectrum corresponds to a point in the chromaticity diagram.
    Chromaticity Diagram PL 03.png
  3. The workbook data that refers to this graph is automatically hidden in the project. You can quickly view the Workbook by going to the Project Explorer and activating the Chromaticity Diagram Workbook. Select the PL worksheet tab. Here the first 4 columns contain the CIE standard observer color matching functions that were used to calculate the xy coordinates.
    Chromaticity Diagram PL 04.png

L*a*b* Plot

  1. Select Folder 2 in the upper panel of Project Explorer. Select Book3, highlight Column B and C, and click the Lab button Lab button.png of this App toolbar.
    Chromaticity Diagram LabPlot 01.png
  2. In the L*a*b* Plot dialog, select 2D Scatter Plot option to open the plotLAB2 dialog.
    Chromaticity Diagram LabPlot 02.png
  3. In the plotLAB2 dialog, follow the setting as below image:
    Chromaticity Diagram LabPlot 03.png

    This graph is created:
    Chromaticity Diagram LabPlot 04.png
  4. Select Graph: Layer Contents to open the dialog. Set Plot Type to Line, select Column F and add to right panel. Click OK
    Chromaticity Diagram LabPlot 05.png
  5. Double-click on the graph to open Plot Detail dialog. Go to Size tab of Layer level, check Link Axis Length to Scale with X:Y Ratio option.
    Chromaticity Diagram LabPlot 06.png
  6. Go to Line tab of the Line plot level. Set Color to White. Check Enable option under Fill Area Under Curve, and select Exclusive broken by missing values in the drop-down list.
    Chromaticity Diagram LabPlot 07.png

    In the Pattern tab, set Fill Color to White. Click OK.
    Chromaticity Diagram LabPlot 08.png
  7. Go to Label tab of Scatter Plot level. Check Enable option. Set Font Color to White, and then select Col(A):"L*" in the Label From drop-down list.
    Chromaticity Diagram LabPlot 13.png
  8. Double-click on the Axis to open the Axis dialog. In the Scale tab, select Both Horizontal and Vertical, then set scale From = 65 and To = -65. Set Major Tick Value =10.
    Chromaticity Diagram LabPlot 09.png

    Go to Title tab. Uncheck Show option.
    Chromaticity Diagram LabPlot 10.png

    Go to Line and Tick tab. Select At Position= in the Axis position the drop-down list, and enter 0 Percent/Value. Click OK.
    Chromaticity Diagram LabPlot 11.png
  9. Draw the symbol label to the suitable position. Finally, you will get the graph like this:
    Chromaticity Diagram LabPlot 12.png