230201 1L2L0X0A_(I), http://farbe.li.tu-berlin.de/AEBI.HTM or
http://color.li.tu-berlin.de/AEBI.HTM
For this main page with general information and special images
of the corresponding image page with 10 colour series, see
AEBI in English,
AGBI in German.
For the previous main page, see
AEAI in English,
AGAI in German.
For the next main page, see
AECI in English,
AGCI 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 AEBI
1. Introduction and goals.
In large shopping centers design-show rooms are created which require an ergonomic
and at the same time a colorimetric colour management to satisfy the customers.
A showmaster can walk within a virtual house from room to room and design the rooms.
The design proposals come from the show master and often from clients. The clients take part
in the design improvement. The show master can fullfil special wishes of the customers.
For example of: wallpapers, floor and sofa. The client may bring a textil sample to cover the sofa.
For this the sample will be scanned. The final design draft shall appear on any display and
in print very similar.
The producer of colour materials require that their products are included in the system,
for example all wallpapers and textil samples. The clients require a device-independent
ergonomic and colorimetric colour reproduction according to ISO 9241-306.
For a sample or video output 16 million rgb colour data must be transfered
to 16 million other data.
These rgb transformations are device dependent and different fo the 15 ISO contrast steps
of any display.
For the ISO-test charts AE49, AE09 und AE19 according to ISO 9241-306:2018 the intended colour
reproduction is shown for up to 15 ISO-contrast steps, see also the figure parts 4 to 9 of
AEBS in english or AGBS in german.
2. Change of rgb-colour data in a colour workflow
Special computer software produces the colour output for the clients. This software steers an
ergonomic and at the same time colorimetric colour output of the projector within the show room.
Often there is much daylight in the show room. If in an extrem case the viewed luminance of the
daylight and the projector on the display is equal, the the contrast ratio of white and black is
YW : YN = 2 : 1. In this case it is valid gP=0,5. This corresponds approximately to the
ISO-contrast step CYP1 with the relative gamma gP=0,475.
In many application cases the relative gamma gP must be changed.
In the standard office with the illuminance 500 lux the gamma gP=1,0
within a dark room and no reflexion must change to gP=0,775 (ISO-contrast step CYP5)
for the 2,5% standard reflection on the display in the office according to ISO 9241-306.
Figure 1 shows the ergonomic colour output of a projector with a colorimetric
colour processor.
For the download of this figure in the VG-PDF format, see
AEB10-3N.PDF.
Figure 2 shows the ergonomic output of a print with a colorimetric colour processor
For the download of this figure in the VG-PDF format, see
AEB11-3N.PDF.
The Figures 1 and 2 include many additional colour data and information.
For a better readability it is recommended to download the figures in the PDF format in vector
graphic VG. This is called VG-PDF format. The output can be magnified 16 times by any PDF reader.
3. Contrast change of ISO-AE49 with 1080 colours in the PG-PDF format in 15 steps.
The following figures 3 bis 6 use a frame file in the VG-PDF format with 16 figures.
All chromatic figures are in the PG-PDF format. The achromatic figures are in the VG-PDF format.
If a figure in PG-PDF format in magnified, then the figure is easy visible as pixel image.
Another main part AGDI includes similar figures.
However, in this main part all frame and figure files are in the VG-PDF format.
The file size is extremely small and one can magnify by a factor 16 without resolution defects.
The change of the ISO-contrast step requires in the case of VG-PDF-figures
in addition a change of at least the three
PS operators setrgbcolor, setcmykcolor, and setgray. This change is therefore more complex.
It has the advantage that the file size remains extrem small and no resolution defects occur.
All PG-PDF figures use the PS operators colorimage and settransfer.
The rgb data are defined in the Hex format and readable. Any figure needs about
6000 lines. The relative gamma gP is changed for the 15 ISO-contrast steps in the range
0,475 <= gP <= 2,105 according to ISO 9241-306.
The corresponding PS operator is {gP exp} settransfer, see for example
AEB50-2N.TXT.
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 3 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
AEB3L0N1.PDF.
Figure 3 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.
For the different standard positions and the numbering, see
AEZ0L0N1.PDF.
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 the absolute gamma ga = 1,8 of the Mac computer-operating system was changed
to ga = 2,4 of the Windows computer-operating system.
This absolute gamma ga = 2,4 corresponds to the relative gamma gP = 1,0. Therefore 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.
If many grey and colour steps are important for the display output,
this ergonomic failure according to ISO 9241-306 leads to a fatigue
and overstress of the visual system. This is often the case for video conferences.
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 12019 the slider "Gamma" is not any more available.
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 PG-PDF file
with pixel graphic 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 with PostScript
is further described in the main part AEZI.
Figure 4 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
AEB5L0N1.PDF.
Figure 4 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.
At the positions 0-1 and 1-1 the contrast step CYP8 is equal. At his positions the formats
are VG-PDF and PG-PDF. Both produce extreme differences with magnification.
With many output questions on 24 pages the ISO-test chart AE49 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 AE49 can be reached from the main ISO page
http://standards.iso.org/iso/9241/306/ed-2/index.html
AE49: 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/AE49/AE49F0PX.PDF
AE49: 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/AE49/AE49F0NX.PDF
4. Contrast change of test chart ISO-AE09 and ISO-AE19 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 AE09,
and the chromatic ISO-test chart AE19.
Figure 5 shows the ISO-test chart AE09 for 5 of 15 ISO-contrast steps.
For the download of this figure in the VG-PDF format, see
AEB6L0N1.PDF.
Visual results show, that the best output of AE09 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 CYP3 instead of CYP5 in the standard office.
.
Figure 6 shows the ISO-test chart AE19 for 5 of 15 ISO-contrast steps.
For the download of this figure in the VG-PDF format, see
AEB8L0N1.PDF.
With many output questions on 24 pages the ISO-test charts AE09 and AE19
can be downloaded. The ISO-test charts are similar to figure 5 and 6 for the contrast step
CYP8.
AE09: 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/AE09/AE09F0PX.PDF
AE09: 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/AE09/AE09F0NX.PDF
AE19: 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/AE19/AE19F0PX.PDF
AE19: 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/AE19/AE19F0NX.PDF
The ISO-test chart AE18 has in addition to AE19 an ISO/IEC image "flower motif".
Properties of this image are described in the main part
AEEI.
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For the archive information (2000-2009) of the BAM server "www.ps.bam.de"
(2000-2018)
about colour test charts, colorimetric calculations,
standards, and publications, see
indexAE.html in English,
indexAG.html in German.
Back to the main page of this TUB web site (NOT archive), see
index.html in English,
indexDE.html in German.