Laboratory tests of paper.

SPM - Security Paper Mill, Inc. it has its own internationally accredited testing laboratory, which is the industry´s only certified laboratory in the Czech Republic.
It provides services in the field of testing physical, mechanical, optical and chemical properties of paper and paper cartons.

Do you have a problem with your paper tearing, having a high dust content, passes light, has poor water absorption or otherwise fails to meet your quality parameters ?

Let our laboratory to determine its actual properties and to find optimal solutions to obtain the desired quality.

The conclusion of laboratory tests will be provided in the form of a certified report.


 1. Whiteness measurement

Optical properties of the paper have a high importance for printing and writing papers. In order to achieve the desired result, we control the amount of raw material: pulp, fillers, coloring additives, glue and brightening additives.

 2. Measurement of print opacity

Opacity is the ability of paper to resist a passage of light. It is particularly important with printing papers, in order to avoid the so-called a color piercing to the other side.

 3. Measurement of color shade

Shades measurement of paper is used mainly in the production of colored papers. The spectrophotometer measures individual coordinates of the color system, which indicates the deviation in color compared to a standard sample.

 4. Determination of basis weight

Basis weight is defined as the quotient of the weight of the examined material and the respective surface area. It is one of the most important characteristics of the paper. It is given in g/m2.

 5. Determination of thickness

Paper thickness is the perpendicular distance between two opposing surfaces. Measured with respect to the compressibility of fibrous structures established under certain measuring pressure. The thickness affects almost all properties of the paper.

 6. Determination of air permeability

Air permeability is understood as the ability of the paper to pass the air due to its porous structure. Permeability decreases with an increase of milling, when disturbed fibers overlap each other.

 7. Determination of water absorption

This test determines the amount of water that is absorbed into the surface of the sample from one side.
Water absorption is an important feature especially during the printing process - as it affects an acceptance and bleeding of color additive. It is also important when considering on savings for printing inks - absorbency rate must be optimal for the paper after the manufacturing.

 8. Determination of tensile strength

Tensile strength of the paper is determined by the strength of individual fibers and the links between them. During the testing process, the sample is subjected to the action of an external load, causing its breakage. We record breaking length, elongation at break and tearing load (tearing point).

Breaking Length (km)

It is an imaginary length of the paper, in which the free-hanging strip of paper breaks at the point of suspension.

Elongation at break (%)

It is the relative elongation of a sample during a tensile test at the moment of breakage.

Tensile loading (KNM)

It is a load at which a strip of paper (with determined length and width) breaks, under specified conditions.

 9. Determnination of tensile strength when wet

The destruction of the paper stability is caused when external mechanical forces exceed the maximum strength. The tensile strength of the paper is determined by the strength of individual fibers and the links between them. A soaking of the paper decreases the strength to 10 % of its original condition. Hydrogen bonds are disrupted with the effects of water. Wet tensile strength is important feature, e. g. in shopping bags and wallpaper.

 10. Determination of the number of double folds

Folding resistance is required for securities which are in practical world constantly bent and crumpled. We determine a point of material disruption at which the paper breaks.
High number of double folds is common with maps and banknotes.

 11. Determination of stiffness

Stiffness of paper is its resistance against deformation by external forces. What is important is the nature of the papermaking furnish from which the paper is made. The rigidity is increased by using short-fiber pulp or by adding the starch. The stiffness depends on the corresponding relative humidity and moisture content.

 12. pH Identification of the aqueous extract

Determining pH of aqueous extract is important in order to establish the alkalinity or acidity of paper.
The samples are extracted in cold or warm distilled water.

 13. Determination of tear strength

It is an amount of strength and needed energy at pre-cut tear sample under specified conditions. A significant drop in values may be due to overdrying of the paper. Higher values can be achieved by increasing the pulp milling (but only up to the point when fibers become too short).

 14. Determination of surface strength

Surface strength is a measurement of the resistance of the paper surface against pulling of the fibers (or coating force) when a perpendicular action is applied to the surface.
Surface strength is an indicator of eligibility for printing as printing inks and rollers cause (thanks to the influence of cohesion) to the fiber on the surface of the paper. When insufficient strength occurs fibers, along with the bond are pulled from the surface.

 15. Determining of the ash content

The ash is non-combustible residue of the filler after a combustion of the paper is completed at a temperature of 900 ± 25 °C.

 16. Determination of roughness

Indication of smoothness (roughness) of the surface has great influence on the choice of printing, following its quality, ... e. g. unprinted missing points. The purpose of this test is to determine the thickness of the ink layer, necessary to fill even the deepest points on the surface.

 17. Calculation of smoothness

Smoothness expresses the mechanical state of the surface of the paper. The pulp furnish has the major impact on the smoothness. It is possible to increase the smoothness with additional milling, or by increasing the filler content.

 18. Determination of grease-proof level

Grease-proofing of paper means resistance against penetration of fat, oil and wax. The resistance of the paper to the penetration of fat is achieved by coating substances on the surface of the paper, creating a continuous film that prevents a fat to be absorbed to the paper.


 1. Determination of density
 2. Determination of specific volume (volumen)

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Pricing for offered laboratory tests at SPM - Security Paper Mill, Inc.: Certificate of laboratory

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