THE COLORIMETRY

¿What is colorimetry?

Colorimetry is the science that measures color. There are different ways to measure colors depending on the medium used. The easiest way is to use a colorimeter. 

¿What is a colorimeter? 

A colorimeter is a device used to define the color of an object's surface in a non-arbitrary way. Primary colors : Red, blue, yellow. 

Secondary colors: violet, orange, green

Tertiary colors: Primary (red) + secondary (orange) = orange red. 

You already know what colorimetry is, it focuses on determining and specifying colors such as hue, saturation and intensity. Colorimetry has application in all areas related to colors, such as photography, advertising, digital art, among others. The types of colors to be used in colorimetry are: intermediate, primary and secondary.

The primary colors are those that cannot be obtained through the mixture of any other color, for this reason they are considered unique, absolute, being magenta, cyan and yellow, although cyan is a color that does not exist within the color chart of many sectors, being characteristic of photography and graphic arts, and this means that the primary colors considered by the stylist or painter do not coincide, for the most part, with the primary colors used in color theory, where several solutions are adopted and among these, one of the possible ones is to use primary colors in watercolor, such as chickpea carmine, medium yellow and cerulean blue.

On the other hand, the secondary colors are those obtained after mixing two of the primary colors in approximately 50%, obtaining: orange, violet or green.

And as for the intermediate colors, they are those obtained after mixing a secondary and a primary. One of the bases of these colors is that they are called tertiary colors.

Application of colorimetry

The types of application of colorimetry will depend on the result we want to obtain. This "science" is mainly focused on capillary use, although its transfer to other areas is not dismissed, it certainly does not fulfill its majority function, so our explanatory approach will be fully in this area.

Why is colorimetry so important for hair? Hair dyes are made by using colorimetry to make variations in the shade they will possess. Strong tones can be seen in the fact that permanent dyes tend to be more durable, and the excessive and misuse of it can sensitize or damage the hair fiber, for this reason it is recommended to people who do not apply outside a beauty salon. Semi-permanent dyes do not have a high hiding power. They can cover up to 70% of gray hair and allow us to obtain more varied and intense colors, providing durability and brightness.

Temporary dyes are only placed on the surface of the hair and disappear with the first wash. There are others that are called by contact and have the ability to last up to 5 washes. In short, the colorimetry is who finishes the level of permanence that the dyes will have based on the intensity that has been applied in it.

Range of colorimetry

Each type of medium has a limited color range, which it is possible to define, linked to the physical constraints of its materials, this is called its range.

The range will be different:

• In painting, which uses natural pigments quite infinitely, and depending on the colors used, the type and amount of material, but also varnishes that allow you to use the light source to add color effects.

• In four-color printing, it is based on three colors and one black, and can not play on light.

• And in video, which is based on only three colors, but projects the light.

Painting

In painting, the colors are made of natural materials (rocks, plants, animals) or artificial (chemical compounds), these different products allow to have a particularly wide range, and the thickness of the medium, its transparency or its chemical properties, are all the possibilities that are offered to the painter. Unfortunately for the painter, modern colorimetric devices are of great interest only in the choice of artificial paints, and the results of these tools can change when applying the fixative or varnish. Colorimetric devices based on the materials used and the names of the colors in the language or languages of the painter are more common.

Colors in the printing press

In printing, the colors are usually composed of a mixture of tiny dots of the three main colors and black: CMYK (cyan, magenta, yellow, black). This color space is called the four-color process.

In some high-end personal printers, there are now 6-color devices, with unsaturated colors being added to expand the range.

Also in some industrial printers, it is also possible to play with the varnish, to reflect more or less light.

In other industrial printers, it is also conceivable to make solid colors or a mixture of several colors, when there are only particularly few different colors to print (generally less than 5). In this case, devices such as Pantone will be used for color calibration. A print of some reference colors will be used, on the edge of the printed sheet, to control the quality of the print. These devices also allow to pose colors, with different properties of use of light, the process of four colors, such as fluorescent colors, or with properties of reflection.

Colors in photography, cinematography and video.

In these techniques, the production of color images is done in three colors. The main colors analyzed are red, green and blue. The subtractive synthesis is then made in photography, film and video, in an additive synthesis. The media (film or electronic sensor) are balanced for a certain color temperature, more often 3200 K (called "color temperature of artificial light") in film and video, 5500 K in photography (color temperature of "daylight"), or 4300K for recent professional video cameras (which accept, without filtering both types of sources).

Good color reproduction is guaranteed when a white beach is restored without coloring (see: photo printing, calibration).

It is therefore essential to know the color temperature of the scene in order to correct it by filtering the fonts or in front of the camera.

The measurement is made with a thermocolorimeter.

Data Processing

In computing, where color management devices are increasingly centralized, there are devices that allow to have references that will be used for different capture devices (camera, scanner, video, etc.) and restitution devices (screen, projector, printer, press ...). The ICC (International Color Consortium), is an international organization, responsible for setting standards in this field. It created the ICC profile format to try to solve the problem.

Colorimetry in chemistry

Colorimetry is a method of determination that consists of sending a monochromatic beam of light through a thick container (l) containing a color solution and measuring the light absorbed by the solution. This measure of absorbed light corresponds to an optical density.

The Lambert-Beer ratio is used to relate the optical density (D) of a solution to its molar concentration (c): D = ε. l. c

ε = specific absorption coefficient of each colored compound (1 and ε are constants for a given experiment)

Therefore, we can establish a linear relationship between D (optical density) and c (concentration).

Note: not to be confused with the color indicator method, sometimes called colorimetric misuse.

color psychology

Dr. Max Lüscher, Swiss professor of psychology, has discovered a color test based on color vision. This test has been used for more than 20 years with great success.

Spectroscopy

Colorimetry is derived from the absorbance technique. For a given molecule, a wavy length can interact with the molecule and decrease the percentage of light from the emission source to the sensor. In colorimetry it is the tone of the compound that creates this effect. This technique is used to create an absorbance curve, defined as the percentage of light transmitted by concentration, which can be used as a standard to determine unknown concentrations.

4 color laws

Colorimetry is governed by the 4 laws of color -which are widely used in beauty salons to achieve the results desired by the customer, taking into account the needs of each. The laws are as follows:

• The first law of color: The cold colors dominate the warm ones, for example, when combining blue and yellow in equal quantities it will give us a color of greater incidence to the blue than to the green, if we want to obtain a green tone the proportions must vary applying more yellow and less blue.

• Second color law: Colors that are opposed to the chromatic circle are neutralized when combined, for example: yellow neutralizes violet; red neutralizes green; and blue neutralizes orange. The result of these color combinations will always be brown (i.e. neutral).

• Third law of color: A dye cannot be lightened with another dye. This law indicates that the processes of capital dyeing require that once the hair has been dyed it cannot be lightened with another dye.

• Fourth law of color: One of the most important rules of colorimetry is that on a warm tone you can apply a cold noto, while on a cold tone you can never apply a warm one. This is because cold tones neutralize warm tones. Light colors allow volume to increase, factions to take advantage and harden. While dark colors dwarf, they thin and harden.

Once you've understood what colorimetry is and what its importance is in the capillary realm, you'll probably be interested to know where "color" comes from. Next, we'll give you a brief summary of the origin and evolution of color throughout history:

Origin and evolution of color

Color has been studied by physicists, scientists, artists and philosophers. Each one in his field established diverse hypotheses that, in diverse opportunities, were elevated points of departure for different studies and for everything that today we know of the color.

It's been almost 35,000 years since we humans expressed ourselves through color. The ancestors decorated and made up their caves. In the cave paintings few colors were used that were acquired from minerals and charcoal, which was mixed with vegetable resins and animal fat, these were: black, red and ochre.

First theories about color

The first theories about color appeared after the arrival of the philosophers.  Aristotle indicated that all colors were formed by the mixture of four basics. The colors of fire, water, earth and sky, that is, the chemical elements of antiquity. It also allowed a fundamental role to be obtained in the incidence of light on objects.

Leonardo Da Vinci

Leonardo Da Vinci, in the Renaissance period, indicated that color was something proper of matter. He established the scale of basic colors: he gave first place to white because it allowed us to receive the rest of the colors; then yellow for earth, green for water, blue for sky and red for fire, and lastly he established black for darkness, because it was he who deprived us of seeing them all.

After the mixture of these colors the rest could be obtained, in spite of also having observed that the green could arise from elaborating a different mixture to the previously mentioned one.

On the other hand, the English mathematician and physicist, Isaac Newton, took a decisive step in the history of color, establishing a principle that is still accepted today: light is color. In 1665 Newton discovered that sunlight, after passing through a prism, is divided into different colors. He also noticed the light in the colors of the chromatic spectrum. These colors are sky blue, violet blue, yellow, green, purple red and orange red.

This phenomenon can be observed after light is refracted at the edge of a plastic or crystal. Also, when it rains different rays of the sun cross the clouds, whereas the drops of the water fulfill the function of Newton's premium after breaking down the light producing the denominated one: Rainbow.

Newton

Newton also noted that natural light is made up of six-colored lights. When it hits one object, it absorbs colors and reflects others. This observation gives rise to the following principle: each of the opaque bodies, when illuminated, reflect part or all of the components of the light they receive.

So, after visualizing a red object, we really realize the surface of a material that has a pigment. Such a pigment has the quality of absorbing the waves that make up white light, with the exception of red light. This color, red, is the wave that the object reflects, our eyes process it and transmit it to the brain so that it can be codified, and allow us to affirm: "This is red".