A/RECS.html

190107 and 081001 A/RECS.html

Relative Elementary Colour System RECS
consists of the analog and the corresponding digital colour atlas

For this page in German
REFS.html

For the DIN-test files according to DIN 33872-1 to -6 (in print)
33872E.html

The Relative Elementary Colour System RECS consists of
- the analog colour atlas RECS_a with real colour samples
- the digital colour atlas RECS_d in the file formats PDF and PS (PostScript)

Analog Colour Atlas RECS_a with about 2000 colour samples

Test production in offset printing (system ORS20_95, L*=20_95)

The digital files of the system ORS20_95, L*=20_95 (Offset-Reflective-System in the lightness range L*=20 to 95) produce an image size DINA4 (27,9 cm x 21 cm) with 9 single pages of the size 10 cm x 7cm. An output magnification by 300% (for example in offset printing or with an image plotter of the size 100 cm x 70 cm) produces in each case 9 pages of the 36 pages of Table 1 in the size DINA4.

Test production with a foto printer (system FRS12_95, L*=20_95)

The digital files of the system FRS12_95, L*=20_95 (Foto-Reflective-System in the lightness range L*=20 to 95) produce directly 18 pages in the size DINA4 (27,9 cm x 21 cm). This foto printer produces equal output for rgb and the equivalent cmy0 data which are defined in DIN E 33872-1 by the "1-Minus-Relation".

Attention: The following files of Table 1 are large with file size in the range between 5 and 10 MByte. The FP-flles produce only a linearized output on the given devices und use the measuerement data of one start output (NP-file with bold file name) on these devices.

For production of analog colour output For production of the pages of the analog atlas Start output
(files ..NP.PDF) Linearized output
(files ..FP.PDF) Start output
(files ..NP.PDF) Linearized output
(files ..FP.PDF)

System ORS20_95, L*=20_95, c=1
Application for cmyk output, if cmyn6* colour separation is possible System FRS12_95, L*=20_95, c<1
Application for rgb output, if cmyn6* colour separation is not possible

Colour atlas RECS_a, start and linerized outputs 1 to 9 L46e00NP.PDF
(not used for offset production) L46e00FP.PDF
(used for offset production) L68e00NP.PDF
(not used for a production) L68e00FP.PDF
(used for a foto printer production)

Colour atlas RECS_a, start and linerized outputs 10 to 18 L47e00NP.PDF
(not used for offset production) L47e00FP.PDF
(used for offset production) L69e00NP.PDF
(not used for a production) L69e00FP.PDF
(used for a foto printer production)

ISO/IEC-test charts, start and linerized outputs 19 to 27 L15e00NP.PDF
(used for offset production) L15e00FP.PDF
(not used for production) (no file, three separations not possible for GDI- printers) (no file, three separations not possible for GDI- printers)

ISO/IEC-test charts, start and linerized outputs 28 to 36 L39e00NP.PDF
(not used for offset production) L39e00FP.PDF
(used for offset production) L13e00NP.PDF
(used for a foto printer production) L13e00FP.PDF
(used for a foto printer production)

Table 1: Files for the start and the linearized output of the analog colour atlas RECS_a and of the ISO/IEC-test charts similar to the ISO/IEC-test charts according to ISO/IEC 15775.

The production files for the offset print and a foto printer are specified by bold letters. The offset print was magnified by 300% (output size 90cm x 63 cm for 9 pages). The output size of the foto printer was directly DINA4.

At first the start output with the NP-file
i
Example file (1 page, 7,5 MByte) L15e00NP.PDF

was produced. This file produces with a printer of the size DINA4 only the smal sizes 10 cm x 7 cm for every page. In the offset print the output was magnified by 300% (see table 1, column 2, bold letters) and produces then the intended size 30 cm x 21 cm (DINA4).

For the print the standard offset process with standard offset colours CMYK on standard offset paper was used. The output of the intelligent separation cmyn6* (down right) serves for the colour measurements. This output is the colour atlas page no. 25 in Table 1.The CIELAB data of the 1080 standard colours were measured for the CIE standard illuminant D65, the CIE 2-degree-observer and the CIE 45-0-degree-measurement geometry.

These measurement data serve for the linearisation of the second output within the FP-files (see Table 1, column 4, bold letters). The produced pages no. 1 to 18 and no. 28 to 36 of the colour atlas are therefore linearized in CIELAB.

Example file (15 pages, 4,5 MByte) L46e00FP.PDF

By a magnification of 300% the offset output of the page no. 2 of this file produces the pages no. 1 to 9 of the colour atlas RECS_a, compare Table 1.

Remarks:
The file in columns 3 and 4 of table 1 are only applicable, if an intelligent cmyn6* colour separation is possible. This is for example the case for offset printing. This output process allows colour separation by the PostScript operator cmyk setcmykcolor. A cmyn6* colour separation is usually also possible for every PostScript printer.

If only an rgb output and therefore no intelligent cmyn6* colour separation is possible, then the files in row 5 and 6 of table 1 may be used. For many so called Graphical Devise Interface (GDI) printers a cmyk colour separation is not possible. This output process uses only rgb data and allows not a colour separation, for example by the PostScript operator cmyk setcmykcolor. Nearly all GDI-printers are designed to output PDF-files with cmy0 data. The rgb data data are then calculated from cmy0-data according to the "1-Minus-Rule", for example c = 1 r. The used foto printer has produced the same output for the two colorimetric equivalent cmy0 and rgb data.

ThePostScript-source code is given in the internet only for the start output by the NP files and not for the linearised output with the FP files. For example ISO/IEC TR 19797 describes a method for output linearisation. According to ISO/IEC TR 19797 the application of an output linearisation method is a requirement for any appropriate colour management method. The standard offset process and calibrated CRT-monitor fullfill approximately the linearisation requirement.

If there is an option "linearized output" in the printer driver then the ouput of the DIN-test charts according to DIN 33872-1 to -6 may fulfill for all the DIN-test the "Yes-criteria".

Any output device may be linearised. For the production of the colour atlas RECS_a the output with the intelligent colour separation cmyn6* was used. The measurement data are used for the calculation of the cmyn6* colour separation data within the FP file. In this case the linrearized outputs with the FP files produce a high material efficiency. A high material efficiency is reached if the achromatic colours are only printed by the black colorant N and not by the overprint of three chromatic colours CMY. The cmyn6*-separation uses approximately a linear increase of the chromatic colorants as function of CIELAB chroma and produces no chromatic jump near the grey scale. Still the visual efficiency is high with a linear increase of standard CIELAB chroma C* as function of the relative CIELAB chroma c* = max (rgb) - min (rgb), see DIN 33872-1.

CIELAB-linearisation for office printers

With a DINA4 office printer the 1080 Standard colours may be printed directly in the output format DINA4. For this start output the following file has been developed:

Example measurement file (11 pages, 1,9 MByte) L59e00NP.PDF

For DINA4 printers the output of the pages 1 and 2 of this file is recommended. The output page no. 2 serves for the measurement. The measurement data serve for the linearisation.

The output page no. 1 shows many output properties of the reproduction process. Many of these output properties are tested in DIN 33872-1 to -6 (in print), see.

33872E.html

The output pages 3 to 11 show many equivalent colour coordinates which are defined in DIN 33972-1 for input and output. The coordinates cmyk6* (page 11) define special cmyk-colour coordinates. Page 11 of the NP-file output (start output) includes the cmyn6*-coordinates defined by a colorimetric and material efficient printing model. For the production of the Colour Atlas RECS_a and the ISO/IEC-test charts (linearized output, compare Table 1) thesecmyn6* data have been corrected. Page 11 of the FP-file output includes the corrected cmyn6*-data, which are calculated within the FP-file with the programming language PostScript from the measurement data of the output produced by the NP-file.

Digital colour atlas RECS_d with about 2000 colour samples

The digital colour atlas RECSd includes equivalent colour coordinates according to DIN 33872-1 (in print). The coordinates are valid
for the CIE standard illuminant D65, the CIE 2 degree observer and the standard offset printing on standard offset paper (files is columns 3 and 4 of table 1).

The CIELAB data deviate a litle compared to the CIELAB data in the International standard ISO/IEC 15775. For the application "Colour in offices" these deviations may be neglected.

The digital colour atlas RECS_d includes equivalent colour coordinates according to DIN 33872-1:
- the digital relative colour coordinates rgb*, olv*, icu* and others
- the adapted CIELAB LAB* a and LCH*a-data and the standard CIELAB data LAB*

For the three motives "hue circle", "5- and 16-step colour series" and "1080 standard colours" it is appropriate to study the colour coordinates at first separately with the following three files (each file produces 11 pages). The colorimetric data are valid for the standard offset process on standard offset paper.

Example file (11 pages, 300 kByte) L50e00NP.PDF

Example file (11 pages, 500 kByte) L51e00NP.PDF

Example file (11 pages, 1,9 MByte) L54e00NP.PDF

All data are valid for the intended cmyn6* colour separation with both a high visual and a high material efficiency.The following file includes all data for the above three motives (198 pages, 10 Mbyte).

L39e00NP.PDF

For further example files for different printers, in different file formats and of different output sizes, see

Fe.HTM

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For information (archive 2000-2009) about International and National Standards, Technical Reports, and Meetings, see
4STAE.html in English or
4STAG.html in German.

For information (archive 2000-2009) about colour test charts and colorimetric calculations, see
indexAE.html in English or
indexAG.html in German.

For publications (archive 2000-2009) of the BAM research group, see
XY91AE.html in English or
XY91AG.html in German.

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For production of analog colour output	For production of the pages of the analog atlas	Start output (files ..NP.PDF)	Linearized output (files ..FP.PDF)	Start output (files ..NP.PDF)	Linearized output (files ..FP.PDF)
For production of analog colour output	For production of the pages of the analog atlas	System ORS20_95, L=20_95, c=1 Application for cmyk* output, if cmyn6* colour separation is possible		System FRS12_95, L=20_95, c<1 Application for rgb* output, if cmyn6* colour separation is not possible
Colour atlas RECS_a, start and linerized outputs	1 to 9	L46e00NP.PDF (not used for offset production)	L46e00FP.PDF (used for offset production)	L68e00NP.PDF (not used for a production)	L68e00FP.PDF (used for a foto printer production)
Colour atlas RECS_a, start and linerized outputs	10 to 18	L47e00NP.PDF (not used for offset production)	L47e00FP.PDF (used for offset production)	L69e00NP.PDF (not used for a production)	L69e00FP.PDF (used for a foto printer production)
ISO/IEC-test charts, start and linerized outputs	19 to 27	L15e00NP.PDF (used for offset production)	L15e00FP.PDF (not used for production)	(no file, three separations not possible for GDI- printers)	(no file, three separations not possible for GDI- printers)
ISO/IEC-test charts, start and linerized outputs	28 to 36	L39e00NP.PDF (not used for offset production)	L39e00FP.PDF (used for offset production)	L13e00NP.PDF (used for a foto printer production)	L13e00FP.PDF (used for a foto printer production)