L*a*b* printed paper, Illuminant D50, 45/0 geometry
Purpose of the test
This test is performed to determine the L*a*b* colour coördinates, using graphic arts spectrophotometers, of a printed colour bar on paper.
Procedure
Operate the instrument in accordance with ISO 13655 and the manufacturer’s instructions.
Leave the samples exposed for 24 h to 23°C and 50% R.H., according to ISO 187.
Adjust the spectrophotometer to the following settings: D50, 2°, Status E – non polarizing.
Place the test piece in the position indicated on the cover sheet on a black backing.
Without touching the test area use the procedure appropriate to the instrument to obtain the L*, a* and b* coordinates.
Report 4 measures of L*, a* and b*, their mean and standard deviation calculated to 3 significant figures.
ISO 13655
Nr. of samples
A pack made of a coloured cover and 2 printed papers.
Each printed paper contains 2 strips with coloured scales
No special size
Levels
Level 1: Black 100%
Level 2: Cyan 100%
Level 3: Magenta 100%
Level 4: Yellow 100%
L*:
Level 1: 15.0÷18.0
Level 2: 54.0÷57.0
Level 3: 45.0÷48.0
Level 4: 85.0÷90.0
a*:
Level 1: 0.2÷0.5
Level 2: -39.0÷-34.0
Level 3: 72.0÷75.0
Level 4: -6.0÷-4.0
b*:
Level 1: 0.5÷1.3
Level 2: -50.0÷-47.0
Level 3: -5.0÷-3.0
Level 4: 92.0÷97.0
Reporting
Report 4 measures of L*, a*, and b*, their mean and their standard deviation. All to three significant digits.