230201 1L2L0X0A_(I), http://farbe.li.tu-berlin.de/AEEI.HTM or http://color.li.tu-berlin.de/AEEI.HTM

For this main page with general information and special images
of the corresponding image page with 10 colour series, see AEEI in English, AGEI in German.
For the previous main page, see AEDI in English, AGDI in German.
For the next main page, see AEFI in English, AGFI in German.

For links to the chapter A Colour Image Technology and Colour Management (2019), 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 image part of 26 parts AEAS to AEZS: AEAS in English or AGAS in German.

Chapter A: Colour Image Technology and Colour Management (2019), Main part AEEI

1. Introduction and goals.

In the main part AEDI the ISO-test charts AE19 and AE29 are changed from the vector-graphic format VG-PDF in another vector-graphic format VG-PDF.

In this main part AEEI a VG-PDF file includes often of the ISO/IEC image "flower motif" in the pixel-graphic format PG-PDF. Therefore a mixture of both formats occurs. The total file is still a VG-PDF file. The total files with the image are called AE18 and AE28. The files without the flower motif are AE19 and AE29.

- The VG-PDF files AE18 and AG28 are still very small, except the part with the image.

- The Pixel structure of the image is disturbing with increasing magnification.

- The other elements of the ISO-test chart can be magnified by a factor 16. A pixel structure is not visible.

The properties of the ISO-test charts AE18 and AE28 are shown in section 3. Many properties of the image "flower motif" are described in section 4.


2. Contrast change of ISO-AE59 with 1080 colours in 12 hue planes in the VG-PDF format in 15 steps.

The display contrast changes with the refection of the environment light on the display. In the standard office with daylight the display contrast also changes with the day time. Therefore defined changes of the gamma values gP are necessary to remain the health of the users and to avoid a fatigue or a overstres of the visual system.


Figure 1 shows on the top left the standard display output for the ISO-contrast step CYP8.
For the download of this Figure in the VG-PDF format, see AEE3L0N1.PDF.

Figure 1 shows the ISO contrast steps CYP8 (position 0-1), CYP1 (position 0-2), CYP5 (position 0-5), CYP6 (position 0-6), CYP8 (position 1-1), and CYP15 (position 1-8). The contrast step CYP8 at the positions 0-1 and 1-1 is identical. This is the standard contrast in a dark room without any reflection on the display. This case is marked by a red continuous square.

The standard display according to ISO 9241-306 has the contrast step CYP5. This case is marked by a red dashed square. For this case the rgb data shall be changed by the formulae in figure 1 with the exponent n = gP = 0,775.

IEC 61966-2-1 (sRGB-colour space) defines the absolute gamma with ga = 2,4. The Mac computer-operating system has used for more than 20 years until 2017 the absolute gamma ga = 1,8 as default value. The value ga = 1,8 corresponds to the relative gamma gP = 1,8/2,4 = 0,75. This is approximately the required value gP = 0,775 for CYP5 (standard office) according to ISO 9241-306.

In 2017 an agreement of the Mac and the Windows computer-operating system with ga = 2,4 was reached. This value corresponds to the relative gamma gP = 1,0. However, now in this point the ergonomic requirements for the display output according to ISO 9241-306 are NOT any more fulfilled for both operating systems.

This ergonomic failure according to ISO 9241-306 leads to a fatigue and overstress of the visual system, if many grey and colour steps are important for the display output.

Until 2018 on the Mac operating system OSX, and in agreement with the first edition of ISO 9241-306:2009 a slider has allowed to change the gamma. With this slider it was possible to adjust the whole display output and not only a file output according to the display contrast. The first and second edition of ISO 9241-306 describes this possibility.

However in 2019 this possibility under "System Preferences - Display - Color - Gamma" was deleted. Since 2019 the slider "Gamma" is not any more directly available.

However, if under "System Preferences - Monitor (Display) - Color"
the "alt"-key is pressed during the choose of "Calibrate"
then an "Expert Mode" turns on.

Then the option "Select Target Gamma" with the "Gamma Slider" between 1,0 and 2,6 allows to choose the appropriate Gamma for the whole display output.

For example the ISO-test chart AG59 (see above) can be used to reach the ergonomic output with equally spaced steps.

Therefore now under the computer operating systems Mac, Windows, and Unix one must look for corresponding possibilities, to fullfil the ergonomic standard ISO 9241-306.

The change of any test chart according to ISO 9241-306 from a VG-PDF file to a PDF file with pixel graphic PG is only one possible way. The up to 15 contrast steps in the figures 3 to 6 have been produced on this line. The technology from VG-PDF to PG-PDF is further described in the main part AEZI.


Figure 2 shows on the top left the ISO-contrast step CYP8 and for the steps CYP1 to CYP15
For the download of this Figure in the VG-PDF format, see AEE1L0N1.PDF.

Figure 2 shows den contrast step CYP8 (Position 0-1) and CYP1 (Position 0-2) to CYP15 (Position 1-8). The contrast step CYP8 on the positions 0-1 and 1-1 is identical. This is the standard contrast step in a dark room. This standard contrast step according to IEC 61966-2-1 is marked by a red continuous rectangle. The ergonomic standard contrast step CYP5 according to ISO 9241-306 is marked by a red dashed rectangle.

With many output questions on 24 pages the ISO-test chart AE59 can be downloaded from an ISO server. This ISO-test chart is on every third page similar to figure 4 and 5 for the eight contrast step CYP1 to CYP8.

The page AE59 can be reached from the main ISO page
http://standards.iso.org/iso/9241/306/ed-2/index.html

AE59: For the 8 ISO-contrast steps CYP1=CYN15 to CYP8=CYN8 on 24 pages, see (1,7 MB)
http://standards.iso.org/iso/9241/306/ed-2/AE59/AE59F0PX.PDF

AE59: For the 8 ISO-contrast steps CYN8=CYP8 to CYN1=CYP15 on 24 pages, see (1,8 MB)
http://standards.iso.org/iso/9241/306/ed-2/AE59/AE59F0NX.PDF


3. Contrast change of test chart ISO-AE18 and ISO-AE28 in the PG-PDF format in 15 steps.

The display contrast changes with the reflection of the environmental light on the display. One can study the visual changes on the achromatic ISO-test chart AE18, and the chromatic ISO-test chart AE28.


Figure 3 shows the ISO-test chart AE18 for 5 of 15 ISO-contrast steps.
For the download of this figure in the VG-PDF format, see AEE2L0N1.PDF.

Visual results show, that the best output of AE18 with 16 approximately equidistant grey steps produces also 16 equidistant chromatic steps, for example from white to device red Rd or green Gd or blue Bd. However, for the visibility of the element Landolt-ring a little lower contrast step seems to be often better, for example for CYP3 instead of CYP5 in the standard office.


Figure 4 shows the ISO-test chart AE28 for 5 of 15 ISO-contrast steps.
For the download of this figure in the VG-PDF format, see AEE4L0N1.PDF.

With many output questions on 24 pages the ISO-test charts AE18 and AE28 can be downloaded. The ISO-test charts are similar to figure 5 and 6 for the contrast step CYP8.

AE18: For the 8 ISO-contrast steps CYP1=CYN15 to CYP8=CYN8 on 24 pages, see (2,2 MB)
http://standards.iso.org/iso/9241/306/ed-2/AE18/AE18F0PX.PDF

AE18: For the 8 ISO-contrast steps CYN8=CYP8 to CYN1=CYP15 on 24 pages, see (2,2 MB)
http://standards.iso.org/iso/9241/306/ed-2/AE18/AE18F0NX.PDF

AE28: For the 8 ISO-contrast steps CYP1=CYN15 to CYP8=CYN8 on 24 pages, see (2,4 MB)
http://standards.iso.org/iso/9241/306/ed-2/AE28/AE28F0PX.PDF

AE28: For the 8 ISO-contrast steps CYN8=CYP8 to CYN1=CYP15 on 24 pages, see (2,4 MB)
http://standards.iso.org/iso/9241/306/ed-2/AE28/AE28F0NX.PDF.


4. Properties of the ISO/IEC-image "flour motif" in the PG-PDF format for four resolutions.

The ISO-test charts AE18 and AE28 in figure 3 and 4 include the ISO/IEC image "flower motif" in two versions based on slide film (sf, AE18) and negative film (nf, AE28). The analog reflective original "flower motif"(about 70cm x 100cm) includes a black and white Siemens-star and test patches.

An equally spaced 16 step grey scale with CIE lightness L* in the range L*=15, 20, 25, ..., 90, 95 was used. The 14 CIE-test colours for colour rendering according to CIE 13.3 include a hue circle and the four elementary colours Red Re, Yellow Ye, Green Ge, and Blue Be (no. 9 to 12) with a high chroma. The taking illuminant was standard illuminant D65. As measuring and taking (viewing) geometry the CIE standard 45/0 degree was used.

Seven different exposures between under to over exposure were used. For the slide film the exposures -1,5, -1,0, -0,5, +0,0, +0,5, +1,0, and +1,5 stops were used. For the negative film the exposures -2,0, -1,0, +0,0, +1,0, +2,0, +3,0, and +4,0 stops were used. The standard Kodak Photo CD process creates the rgb-colour data as function of exposure and for the two film materials.


Figure 5 shows the input - output relationship for slide film sf (left) and Negativfilm nf (right).
For the download of this figure in the VG-PDF format, see AEY1L0N1.PDF.


Figure 6 shows the input - output relationship for slide film sf with the exposure +0,5.
For the download of this figure in the VG-PDF format, see AEY10-6N.JPG.


Figure 7 shows the input - output relationship for negative film nf with the exposure +1,0.
For the download of this figure in the VG-PDF format, see AEY11-5N.PDF.

By output linearization of the standard rgb values of the Photo CD the intended ergonomic relationship was reached, see the dashed black line. The three relations for the rgb data are nearly perfect, and are therefore located under or near the dashed line. Fore more information about output linearization see the Reportership Report CIE R8-09 (only download for CIE members) or a paper of Richter with approximately the same technical content, see
http://farbe.li.tu-berlin.de/OUTLIN16_01.PDF


Figure 8 shows the flower motif for slide film with the exposure +0,5.
For the download of this figure in the VG-PDF format, see AEE61-3N.PDF.


Figure 9 shows the flower motif for negative film with the exposure +1,0.
For the download of this figure in the VG-PDF format, see AEE71-3N.PDF.

Visual inspection lead to the result that it is hard to see differences between the film material slide film (sf) and negative film (nf). This is similar for exposure variations of slide film in the range between -0,5 and +1,5 stops, and of negative film in the range between -1,0 and +3,0 stops.

The exposure range is about four stops for negative film and two stops (half) for slide film. The output linearization method produces in this exposure ranges images which appear approximately identical.

For other resolutions and in addition images with cmyk instead of rgb data go to the image part AEES.

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about colour test charts, colorimetric calculations, standards, and publications, see
indexAE.html in English, indexAG.html in German.

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