How is it possible to be sure that the same object does not present colour differences?
We discover it in this article, read on because today we talk about the main colour measurement instrument: the colorimeter.
You will understand all its features and you can see it in action in the video we made for you.

What is a colorimeter?

Colour difference meter is a device used to measure chromatic differences, which allows performing accurate measurements of differences between all colour types of the same material, according to the international standards.

Objects’ colour

Design colour’s choice is extremely important, even if is quite subjective.

Colours arouse emotions and this particular emotion may differ from person to person.

Studying how colours influence people is a real kind of business.

The simple change of a tone or a saturation is enough to arouse completely different feels.

Moreover even cultural differences should be considered, because what means happiness somewhere, could means sadness in somewhere else.

Our Logo, for instance, RED and BLUE show different meanings between Orient and Occident.

• Occident: excitement, love, passion
• Orient: wedding dress, joy

• Occident (Europe): relaxation, confidence
• Orient: sadness, depression, wedding tradition, prudence

Color perception

What is really important for any producer is to be able to reproduce the chosen colour without facing the risk of visual errors.

Light, object and observer are three essential components in colour perception.

The variation of one of these three components changes inevitably the colour perception.

In the event that light and observer do not change, the object will define the observer’s colour perception.

The object can influence colour perception because his reflective surfaces (transmittance surfaces) modulate the spectrum of the light source.

Each object has several reflectivity surfaces, these one are modified by the light source obtaining various results.

The same observer, but different colours perceived.

The colorimeter help us to measure chromatic differences.



Calibration report for the colour difference meter

An optional service for the colour difference meter is the calibration report.

It is a document edited by metrological laboratories that insures that the test has been made with reference to national acknowledged samples.

The technical worthiness of these documents is based on the laboratory’s qualification, on the operator’s expertise and by the metrological procedures employed.


Application fields

Colour meters are able to operate on plastic, metal, printings and painted surfaces.

They are mainly employed to perform quality checks on incoming and outgoing goods.

How the colorimeter works?

The colour meter operating principle bases on the measurement of chromatic aspects of the light that arrives on the surfaces from any source, directly or indirectly.

Suitable for intermediate stages analysis in producing materials such as:

  1. Clothes
  2. Building
  3. Interior design
  4. Plastics
  5. Paints
  6. Facings
  7. Porcelains



It is a perfect device to be used for field measurement.





It is used to check chromatic differences between samples of the same material in a fast and accurate way.


Would you like more information or assistance?

If you are looking for further information on a specific color meter model or want to know more, contact our technical department. You can call us at 0584/392342 – 0584/392453 or, alternatively, fill out the form.


What is the salt spray test?


The salt spray test is a standardized test method used to check corrosion resistance of coated samples.

During the salt spray test, an accelerated corrosive attack is produced in order to predict the coated samples suitability in use as a protective finish.

Salt spray tests are generally employed to produce rapid comparisons between expected and real corrosion resistance.



Salt spray test

How the test works?

Tests are carried out in a closed testing chamber.

A salt-water solution is applied to a sample through a spray nozzle.

This produces a corrosive environment of dense saline fog to emulate a corrosive experiment.

The appearance of corrosion products (oxides) is evaluated after a period.

The more corrosion resistant the coating is the longer will be the period in testing without showing signs of corrosion.

Tests can take between 24 and over 1000 hours for certain coatings.



Salt spray test

Which is the UNI reference standard?

The reference standard is UNI EN ISO 9227: 2006: Corrosion tests in artificial atmospheres – Salt fog tests.

It defines the equipment, reagents and procedures that must be used to perform the tests in neutral salt spray (NSS), salt spray-acetic (AASS) and cupro acetic salt spray (CASS).

The aim is to evaluate the corrosion resistance of metallic materials, with or without permanent or temporary anti-corrosive protections.

The standard does not indicate the duration of the salt spray tests since it is indicated by the product standards.




Salt spray test

Why a salt spray cabin is so useful?

The resistance results of a material or coating to corrosion in a salt spray test is useful to determine the strength of a particular fastener or coating for the purpose of your production needs.

Watch the salt spray cabin test!




The glossmeter performs measurement on flat surfaces and operate like a refractometer.
Gloss and brightness of a particular surface is measured in “Gloss” and it is an optical property, based on the relationship between light and the physical characteristics of the surface, which means the surface capacity to reflect light in a specular way.

Gloss importance

Brightness is one of the most important parameters of a surface, because it can alter the perception of profiles and shapes, influencing the visual experience.

Brightness acts on the surfaces according to different aspects: angle of incidence of light, observer position, physical properties of surface and observation conditions.

This parameter plays a key role in several production sectors where metrological instruments are relevant in order to standardise the quality control.

Brightness measurement was consolidated according to international methods approved by ASTM, DIN e ISO.

Basic physical principle for gloss measurement

When a light source radiates a surface undergoes a double effect: partly dispersed, partly reflected with opposite angle but with equal amplitude, with respect to the initial radiation.

The brightness of a surface is calculated according to this specular reflection.

This last element determines the gloss level of a surface.

Specular reflection intensity is determined by the material and angle of incidence of the illuminating measured according to certain conditions.

Measurement scale

Values are conventionally expressed in units of gloss (GU : gloss units) and they refer to a scale based on the index of refraction of a black glass mirror with a reflection 100GU in relation to a specific angle.

All non-metallic materials, such as paints or plastics, can have a value associated to this data, while for highly reflective metal surfaces, such as laminates and other crude materials, the user can measure get up to 2000GU.

Geometry Types – When and Which one to Choose?

Gloss meters are divided into two types, mono-angle (60°) and tri – angle (20°/60°/85°).

To have more angular references of the illuminant allows improving measurement accuracy according to the level of brightness of the surface.


• Measurements at 20° are more indicated for very bright surfaces;
• Measurements at 60° are more indicated for medium bright surfaces;
• Measurements at 85° allow to obtain optimized values for little bright surfaces.

60° geometry is widely used thanks to its range of median use, however it is recommended to refer to 20° value for measurements above the 70GU, while 85° is preferred for measurements under 10GU.

Example: Measurement of the specular brightness of a painting film

The moment we are going to paint a wall, we need to decide even about the finish: matt, satin or glossy?

Colour can change according to the brightness grade.

EN ISO 2813 provides for the use of the gloss meter to measure the mirror brightness of a painting film.

Caparol Media, the web portal for colour, decoration, isolation and restoration, shows us in 5 steps how to make measurements.


1. Prepare the sample to be measured by applying a paint film and let it dry at 23°C and with 50 % UR;
2. Wait 16 hours for conditioning at constant temperature and RH rate;
3. Calibrate the gloss meter
4. Repeat the measurement six times in different positions, in a parallel and perpendicular direction to the drafting of the film;
5. Calculate the average of measured values and identify the reference ranges.


Upon request, we can carry out calibration report on the whole instrument or on the different angles (20°-60°-85°).

Which are the 5 strength points of the 3 angles digital glossmeter by Sama Tools?

  • Attractive design
  • Compact size
  • Three-angle geometry of the lamp
  • High-precision
  • Ideal for quality control on production line or in the field

Thanks to the master supplied with the instrument, calibration could be performed in few seconds.

The 3 detection geometries, respectively 20°, 60° and 85° allow maximum flexibility of use, covering low, medium and high brightness surfaces.



Glossmeter applications:

– Brightness measurement of ink, paints, sealing wax prints.
– Cladding and processed wood products
– Decorative building materials: marble, granite, glass, glass blocks, etc.
– Plastics or papers

Who was the inventor of the glossmeter?

According to Wikipedia, the first one who realize an instrument for brightness measurement (of paper) was Ingersoill in 1914.

The “Glarimeter” (as it was initially called), was based on the principle that light was polarized in a specular way.

The light was incident at an angle of 57.5 ° and employed a contrast method to subtract the specular component from the reflected light with a polarizing element.





What is a Gauge block?

The Gauge block consists in a parallelepiped, which works to obtain two opposing parallel faces, spaced apart by a precise altitude (nominal thickness).
These Gauge blocks are also called Johansson blocks, in honour of the Swedish Carl Edvard Johansson, who certified them.


The beginning of modern industry

Even if the inventor’s history is not well known, his gauge blocks created the modern industry, making the present day mass production possible.

Around 1890, he started to work in the Carl Gustafs Stads’ rifles factory in Eskilstuna, where he became Chief Inspector.

His main task was to verify different metrological instruments employed in weapons manufacture, which was the first mass production of that time.

The weapons manufacture requires a great precision, so that each part should have the same sizes.

In 1897 Johansson created his first gauge blocks’ set, but his fight to obtain the Swedish patent lasted up until 1904, while the English one was obtained two years before.

In 1903 his invention received a silver during an exposition in Paris.

In 1923 he moved on the USA being taken by Henry Ford, the car’s inventor.

In the lobby of Ford’s firm there was a glass furniture with a British Encyclopaedia together with a Johansson’s gauge blocks set.

Both were very significant in Ford’s opinion, so he trusted CE Johansson a lot.




Johnson’s gauge blocks box

Gauge blocks are rarely used alone, they are usually bought and used in series with several pieces.


Kit shows different size blocks, creating several calipers throughout arithmetical combinations.

Johnson’s ACCREDIA gauge blocks

SAMA tools’ gauge blocks are made up of particular steel and are employed as “primary reference standards” in order to calibrate and control other blocks, other equipment or to check working operations.