To communicate a colour without using a standard reference is difficult. Therefore colour needs to be measured so that it is identified with a numerical value to distinguish it from the others.
By bearing this in mind, we have adopted the best technology available in the colorimetry field, which, together with the experience of our technicians, ensures that our inks fully comply with the colour quality requested by our customers.
Offset, flexographic and gravure printing on newspaper, books and packaging: Colorprint offers you a large kind of solutions for your printing requirements.
DEFINITIONS
Light Resistance
The light resistance of an ink means the resistance of a sample print to the solar or artificial light issued by a test instrument.
The test is carried out by exposing the print to solar light or inserting it in the test instrument (Sun Test) with the blue scale, which consists of eight standard wool colours (eight values of the light resistance index) and controlling the hours of exposure (resistance hours).
The values relating to the light resistance of the ink are obtained by comparing the colour variation of the sample with the colour difference on the blue scale as shown in the table below.
Definitions of the data in the table:
Values below 3: do not allow exposure to direct sunlight;
Values up to 5: allow limited print exposure to sunlight, since in half-tones resistance values lower considerably;
Values over 5: allow to carry out works for which resistance to light is required.
ALKALI RESISTANCE This refers to the resistance of a well dried ink to a solution diluted with caustic soda at a rate of 2.5% of weight: the solution must neither take on a colour nor must a degradation of print colour take place.
NITRO RESISTANCE This refers to the capacity of the ink not to "bleed" under the effect of nitro varnish solvents and plasticizers.
Tests are carried out with the following reagents:
Indicative mixture of:
ALCOHOL RESISTANCE
This refers to the capacity of the ink not to "bleed" under the effect of the alcohol in the varnish.
N.B.: As far as resistance to alkali, nitro and alcohol is concerned, the following table is usually referred to:
1 = null resistance
2 = average resistance
3 = fair resistance
4 = good resistance
5 = Very good resistance
To be more practical and safe when carrying out the work, we prefer to use the following symbols:
(+) = value 5 resistance
(+/-) = value 4/4.5 resistance
(-) = lower resistance values
DRYING Drying index
1 =
OXIDATIVE ink
Drying index
2 =
SEMIWET ink (overnight)
Drying index
3 =
WET ink