210810 1L2L0X0A_(I), http://farbe.li.tu-berlin.de/AEXI.HTM oder http://color.li.tu-berlin.de/AEXI.HTM
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For this main page with general information and special images
of the corresponding image page with 10 colour series, see
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For links to the chapter A Colour Image Technology and Colour Management, see
Content list of chapter A: AEA_I in English or AGA_I in German.
Summary of chapter A: AEA_S in English or AGA_S in German.
Example content part AEAI of 26 parts AEAI to AEZI: AEAI in English or AGAI in German.
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For links to the chapter B Colour Vision and Colorimetry, see
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Summary of chapter B: BEA_S in English or BGA_S in German.
Example content part BEAI of 26 parts BEAI to BEZI: BEAI in English or BGAI in German.
Example images part BEAS of 26 parts BEAS to BEZS: BEAS in English or BGAS in German.

For links to the chapter C Colour Spaces, Colour Differences, and Line Elements, under work, see
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Summary of chapter C: CEA_S in English or CGA_S in German.
Example content part CEAI of 26 parts CEAI to CEZI: CEAI in English or CGAI in German.
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For links to the chapter D Colour Appearance, Elementary Colours, and Metrics, under work, see
Content list of chapter D: DEA_I in English or DGA_I in German.
Summary of chapter D: DEA_S in English or DGA_S in German.
Example content part DEAI of 26 parts DEAI to DEZI: DEAI in English or DGAI in German.
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Chapter A: Colour Image Technology and Colour Management, Main part AEXI

1. Introduction and goals.

This main page shows the structure, the names and the content of many parts of this TUB web server. The creation and use of ICC-profiles and the PS operator settransfer is shown. The PS operator settransfer and the created profiles change the ISO-contrast step between CYP1 (low) and CYP8 (high).

The input-output relation between CIE lightness L* and 8bit-rgb data is shown. The input-output relation is especially considered for the 1080 colours of the test chart AE49 of ISO 9241-306.

The computer operating system Mac OS V10.8.7 allows the continuous change of the absolute Gamma ga in the range 1,0 to 2,6. The contrast of the display output changes then from low to high.

The Mac software Grab for the storage of the display output captures not the contrast change of the display output, see Figure 4.

The transfer of the tiff-pixel file in an eps-pixel file with the Mac software GraphicConverter X V5.2 allows a simulation of the visual contrast change of the display output. In Figure 10 the four chosen values ga=1,2, 1,6, 2,0, and 2,4 are captured.

Inclusion of the four PS operators {gP exp settransfer} with gP=0,50, 0,67, 0,83, 1,00 creates the intended contrast change towards ga=1,2, 1,6, 2,0, 2,4.

The 15 contrast steps CYP1 to CYP15 or CYN15 to CYN1 in the reverse (negative) ordering are shown on one page in Figure 7.

A corresponding figure without any contrast change serves for the assessment of the question, if the visual display output at the four corners: top and down and left and right are equal.

The equal display output may change visually by the reflexion of the ambient light. In addition different viewing angles in the direction of the 1080 colour in the four corners may change the colour-step recognition.

2. Content, structure and names of many web pages and figures


Figure 1: Content of four main parts A to D of the TUB-web site.
For the download of this figure in the VG-PDF format, see AEX00-7N.PDF.


Figure 2: Structure and names of the main part C of the TUB-web site.
For the download of this figure in the VG-PDF format, see AEX00-3N.PDF.


Figure 3: Structure and names of the main part D of the TUB-web site.
For the download of this figure in the VG-PDF format, see AEX00-4N.PDF.

The first four characters of a name, for example AEX0, include the main web page A, the language (G=German, E=English), the figure page (A, B, C, ...,Z), and the figure-part page (0, 1, ..., 9). Figure 3 shows the coding on the left page (0-1, 0-2, ..., 0-8), and the right page (1-1, 1-2, ..., 1-8). A figure may consist of one or more pages (N or A).

The extension describes the figure format. Usually vector-graphic files are described with capital letters in the formats PS, PDF, TXT, JPG, and TIF. Usually pixel-graphic files use small letters for the formats eps, pdf, txt, jpg und tif.

3. Gamma calibration with Mac OS V10.7.5 and display output of 1080 colours


Figure 4 shows an A4 page with four Figures which are captured for the absolute Gamma ga = 1,2, 1,6, 2,0, and 2,4 by the application Grab.
For the download of this figure in the VG-PDF format, see AEX1L0N1.

The four Gamma values change the contrast between low and high for the display output. However, this change ist not captured by the application Grab.


Figure 5 shows an A4 page with four figures similar to Figure 4.
Each tif figure of the application Grab in Figure 4 was transferred to an eps figure. By inclusion of the PS operator {n exp settransfer} with n=0,50, 0,67, 0,83, 1.00 the visual figure output is simulated. This change is not captured in Figure 4.
For the download of this figure in the VG-PDF format, see AEX2L0N1.

According to the four Gamma values the contrast changes now between low and high for the display output. However, this change ist not captured by the application Grab, and is simulated.

4. 1080 standard colours at 16 standard positions similar to ISO 9241-306:AE49 for up to 15 ISO-contrast steps CYP1 to CYP15


Figure 6 shows 1080 standard colours at 16 standard positions similar to ISO 9241-306:AE49 for the ISO-contrast step CYP8.
For the download of this figure in the VG-PDF format, see AEX6L0N1.

The output is repeated here 16 times. With directed reflexes from the display in the direction of the viewer, for example by a window or the room illumination, the recognition of the colour colour steps may be different, for example at the four corners: left and right and st top or down.

By a tilt of the display or an other position the ergonomic situation can be improved fo the display viewer. This is often necessary to avoid a unwanted fatigue by the display work.


Figure 7 shows 1080 standard colours at 16 standard positions similar to ISO 9241-306:AE49 for 16 ISO-contrast steps CYP1 to CYP15.
For the download of this figure in the VG-PDF format, see AEX8L0N1.

At 16 standard positions the ISO-contrast step changes between CYP1 and CYP15. At the standard positions 0-8 and 1-1 the ISO-contrast step CYP8 is equal. This is marked by a red rectangle. In a dark room without any reflexion of the ambient light according to IEC 61966-2-1 (sRGB-colour space) the output shows the optimale recognition of the colour steps and equal spacing of the 9 step series..

In the standard office with the illumination 500 lux and according to ISO 9241-306 2,5% of the ambient light are reflected in relation to the luminance of the white display (100%). Then the ISO-contrast step changes from CYP8 to CYP5. This case is marked by a dashed red rectangle. In the standard office the ISO contrast CYP5 shows the optimale colour-step recognition.


Figure 8 shows 1080 standard colours at 16 standard positions similar to ISO 9241-306:AE49 for the ISO-contrast step CYP5.
For the download of this figure in the VG-PDF format, see AEX7L0N1.


Figure 9 shows 1080 standard colours at 4 standard positions similar to ISO 9241-306:AE49 for the ISO-contrast steps CYP(2, 4, 6, 8)
For the download of this figure in the VG-PDF format, see AEX9L0N1.

5. Creation of colour profiles with Mac OS V10.7.5 and use on computers


Figure 10 shows four figures which are captured for four absolute Gamma values ga = 1,2, 1,6, 2,0, and 2,4 by the application Grab.
For the download of this figure in the VG-PDF format, see AEX5L0N1.

According to the four Gamma values the contrast step changes between low and high for the display output. However, this change is not captured by the application Grab. The change is similar to Figure 4 also simulated in Figure 10.


Figure 11 shows one magnified figure which is captured for the absolute Gamma value ga = 1,6.
For the download of this figure in the VG-PDF format, see AEX50-7N.PDF.

By the following options Admin and Name a profile with the name LCD_16.icc is stored. According to the default for this the folder Library/ColorSync/Profiles/Displays is used.

In total nine profiles with the names between LCD_10.icc and LCD_26.icc are stored. These profiles can be used with the computer-operating systems Mac and Windows. The names appear as profiles for the display output, if they are copied in the corresponding folders.


Figure 12 shows the URLs for the Download of the nine 9 profiles with the names between LCD_10.icc and LCD_26.icc
For the download of this figure in the VG-PDF format, see AEX01-1N.PDF.

By a preceding choice with Figure 7 the optimale display output can be determined, for example the ISO-contrast step CYP5 in the standard office. The profile LCD_18.icc corresponds approximately to this ISO-contrast step CYP5. By a click on the profile LCD_18 then the office work can be done with the optimale colour-step recognition.

An alternative Method is a click of one of the eight profiles. Any click changes the contrast of the whole display output. For example with Figure 6 on the display the profile for the optimale colour-step recognition can be determined. Usually in any use case the optimale recognition can be determined.

The profile for the optimale colour-step recognition depends on changes of the illumination and the reflexion from the display. For example at a work place with daylight the illumination changes during the day time.


Figure 13 shows the use of a profile and the alternate use of the PS operator settransfer.
For the download of this figure in the VG-PDF format, see AEX01-3N.PDF.

If the software agrees to the Adobe PostScript Reference Manual, then the output is equal. Remark: I am not an expert of profiles and appreciate, if someone can mail profiles for the 8 or 15 ISO-contrast steps. These profiles may be created by mathematical methods according to ISO 20677:2019 or the methods given on the ICC web site. I may prepare these profiles for download similar as in AEX01-1N.PDF with the author name.

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