FograCert Ink Colour
Certification for printing inks based on ISO 2846
ISO 2846 defines the ink mileage, the transparency and particularly the colour of printing inks for process printing. Printing inks for the different printing processes are addressed in separate sections (Section 1 for sheet-fed offset printing and web offset heat-set printing, Section 2 for newspaper printing, Section 3 for gravure, Section 4 for screen printing and Section 5 for flexographic printing). All drying mechanisms are covered. Inks meeting the criteria of ISO 2846 are required for standardised working according to the ProcessStandard Offset printing and ISO 12647 respectively.
Even though the printing ink standard ISO 2846 does not specify the use of defined pigments, only certain standard pigments are used for pigmentation (pigment Yellow 13, pigment Red 57:1, pigment Blue 15:3 and pigment Black 7). Especially in the case of organic chromatic pigments, different types are provided by the chemical industry; these are distinctly different from one another with regard to their transparency and their colour location. This can have the result that in spite of using pigments of the mentioned types, colour and transparency variations occur. While research work at Fogra in 2005 in the area of conventional sheet-fed offset printing inks for German manufacturers could establish only concurrence with ISO 2846-1, in case of tests with UV printing inks the following year, clear variations were already seen. Hardly any of the tested UV colour sets demonstrated conformity to ISO 2846-1 for all four process inks simultaneously.
Fogra offers the possibility of testing printing ink sets according to ISO 2846 and certifies printing ink sets complying with the criteria. The test of UV printing inks according to ISO 2846 takes place as part of the material tests that were developed in cooperation with KBA and Heidelberger Druckmaschinen AG.
Testing takes place by producing a series of specimen prints (approx. 8) on APCO II/II with black pre-print with the help of a printability tester. The test prints are dried immediately after printing according to the particular drying requirements of the ink. Specimen prints with conventionally drying sheet-fed offset printing inks are stored for 24 hours in standard climatic conditions. The attainment of the reference colour coordinates in the specified layer thickness area is measured on a white backing using colorimetry according to ISO 13655. The test prints are tested colorimetrically for their colour coordinates before and after printing in the black preprint to determine the transparency of the chromatic inks. If the colour location of the black changes significantly due to overprinting with the chromatic inks, then the transparency of the chromatic printing inks is too low.
Price (per colour set and excl. VAT)
Certification for conventionally drying sheet-fed and news printing inks: € 2.076.00
Fogra members: € 1,453.20
Certification for UV curing and heat-set printing inks: € 2,336.00
Fogra members: € 1,635.20
The certificates are valid either until the ink formulas are altered or for a maximum of two years.