ISO 12645 pdf download.Graphic technology — Process control — Certified reference material for opaque area calibration of transmission densitometers
1 Scope
This International Standard defines requirements for a half-tone certified reference material which may be used for the opaque area percentage calibration of transmission densitometers or colorimeters for use in the graphic arts. This International Standard is not applicable to the calibration of transmission densitometers in terms of ISO standard diffuse density. NOTE Test methods for determining the opaque area percentage are given in the informative annex A.
2 Normative reference
The following normative document contains provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 1 2647-1 :1 996, Graphic technology — Process control for the manufacture of half-tone colour separations, proof and production prints — Part 1 : Parameters and measurement methods.
3 Definitions
For the purposes of this International Standard, the definitions given in CIE 1 7.4 and the following apply. They are given in alphabetical order. NOTE For quantities, the preferred unit is given together with the definition. By definition, the unit of formerly so-called “dimensionless quantities” is 1 . 3.1 control patch area produced for control and measurement purposes [ISO 1 2647-1 ] 3.2 core density transmission density in the centre of an isolated opaque image element such as a half-tone dot or line Unit: 1 [ISO 1 2647-1 ] 3.3 fringe width (of an isolated opaque image element) average distance between the density contour lines corresponding to 1 0 % and 90 % of the minimum core density specified for the printing process under consideration Unit: µm [ISO 1 2647-1 ]
4 Requirements
4.1 Materials The substrate shall consist of a clear material with a pattern of opaque half-tone dots on one side. At normal incidence the (absolute) reflectance factor (front and second surface) shall not be higher than 0,05. 4.2 Thickness The nominal thickness shall be selected from the range 0,1 mm to 0,8 mm. The measured thickness shall not vary by more than 0,01 mm across the certified reference material. 4.3 Half-tone pattern The certified reference material shall show control patches whose minimum sizes shall be greater than 5 mm in diameter and should not be smaller than 1 0 mm in diameter. The shape of the half-tone dots shall be nominally circular. The screen ruling shall be selected from the range 50 cm -1 to 70 cm -1 , it shall be constant over the certified reference material. The certified reference material shall show control patches with at least the following opaque area percentages: • circular opaque half-tone dots: 20 % or 25 %, 50 %; • circular clear half-tone dots: 75 % or 80 %. In addition, control patches showing 0 % and 1 00 % (solid) shall be provided. Control patches with 2 % and 98 % should be provided as well. Deviations of 1 % (absolute) shall be permitted for the choice of the nominal opaque area percentage. All control patches should be labelled with the nominal opaque area percentages. The fringe width of the half-tone dot pattern (see the informative annex D) should not be greater than 2 µm as determined by the apparatus described in ISO 1 2647-1 . The ISO Status A (blue) and the ISO visual standard diffuse transmission density of the solid (opaque) control patch shall exceed 4,00, the core densities of the half-tone dots shall exceed 3,00. The ISO Status A (blue) transmission density and the ISO visual standard diffuse transmission density of the clear substrate shall not exceed 0,04, the ISO type 1 printing density of the clear substrate shall not exceed 0,06. All clear areas shall have the same density. NOTE In case of a chromium/glass c