Perfume types reflect the concentration of aromatic compounds in a solvent, which in fine fragrance is typically ethanol or a mix of water and ethanol. Various sources differ considerably in the definitions of perfume types. The intensity and longevity of a perfume is based on the concentration, intensity, and longevity of the aromatic compounds, or perfume oils, used. As the percentage of aromatic compounds increases, so does the intensity and longevity of the scent. Specific terms are used to describe a fragrance’s approximate concentration by the percent of perfume oil in the volume of the final product. The most widespread terms^[24] are:

• parfum or extrait, in English known as perfume extract, pure perfume, or simply perfume: 15–40% aromatic compounds (IFRA: typically ~20%);
• esprit de parfum (ESdP): 15–30% aromatic compounds, a seldom used strength concentration in between EdP and perfume;
• eau de parfum (EdP) or parfum de toilette (PdT) (The strength usually sold as “perfume”^[24]): 10–20% aromatic compounds (typically ~15%); sometimes called “eau de perfume” or “millésime”; parfum de toilette is a less common term, most popular in the 1980s, that is generally analogous to eau de parfum;
• eau de toilette (EdT): 5–15% aromatic compounds (typically ~10%); This is the staple for most masculine perfumes.
• eau de Cologne (EdC): often simply called cologne: 3–8% aromatic compounds (typically ~5%); see below for more information on the confusing nature of the term “cologne”;
• eau fraiche: products sold as “splashes”, “mists”, “veils” and other imprecise terms. Generally these products contain 3% or less aromatic compounds and are diluted with water rather than oil or alcohol.^[24]

There is much confusion over the term “cologne”, which has three meanings. The first and oldest definition refers to a family of fresh, citrus-based fragrances distilled using extracts from citrus, floral, and woody ingredients. Supposedly these were first developed in the early 18th century in Cologne, Germany, hence the name. This type of “classical cologne” describes unisex compositions “which are basically citrus blends and do not have a perfume parent.”^[25] Examples include Mäurer & Wirtz’s 4711 (created in 1799), and Guerlain’s Eau de Cologne impériale (1853).

In the 20th century, the term took on a second meaning. Fragrance companies began to offer lighter, less concentrated interpretations of their existing perfumes, making their products available to a wider range of customers. Guerlain, for example, offered an eau de Cologne version of its flagship perfume Shalimar. In contrast to classical colognes, this type of modern cologne is a lighter, diluted, less concentrated interpretation of a more concentrated product, typically a pure parfum. The cologne version is often the lightest concentration from a line of fragrance products.^[25]

Finally, the term “cologne” has entered the English language as a generic, overarching term to denote a fragrance worn by a man, regardless of its concentration. The actual product worn by a man may technically be an eau de toilette, but he may still say that he “wears cologne”. A similar problem surrounds the term “perfume”, which can be used in a generic sense to refer to fragrances marketed to women, whether or not the fragrance is actually an extrait.

Classical colognes first appeared in Europe in the 17th century. The first fragrance labeled a “parfum” extract with a high concentration of aromatic compounds was Guerlain’s Jicky in 1889. Eau de toilette appeared alongside parfum around the turn of the century. The EdP concentration and terminology is the most recent. Parfum de toilette and EdP began to appear in the 1970s and gained popularity in the 1980s.

Imprecise terminology

Different perfumeries or perfume houses assign different amounts of oils to each of their perfumes. Therefore, although the oil concentration of a perfume in EdP dilution will necessarily be higher than the same perfume in EdT from within a company’s same range, the actual amounts vary among perfume houses. An EdT from one house may have a higher concentration of aromatic compounds than an EdP from another.

 The wide range in the percentages of aromatic compounds that may be present in each concentration means that the terminology of extrait, EdP, EdT, and EdC is quite imprecise. Although an EdP will often be more concentrated than an EdT and in turn an EdC, this is not always the case. J.B. Filz in Vienna. Perfumeries with long traditions, such as J.B. Filz, created their own scents. Furthermore, some fragrances with the same product name but having a different concentration may not only differ in their dilutions, but actually use different perfume oil mixtures altogether. For instance, in order to make the EdT version of a fragrance brighter and fresher than its EdP, the EdT oil may be “tweaked” to contain slightly more top notes or fewer base notes. Chanel No. 5 is a good example: its parfum, EdP, EdT, and now-discontinued EdC concentrations are in fact different compositions (the parfum dates to 1921, whereas the EdP was not developed until the 1980s). In some cases, words such as extrême, intense, or concentrée that might indicate a higher aromatic concentration are actually completely different fragrances, related only because of a similar perfume accord. An example of this is Chanel’s Pour Monsieur and Pour Monsieur concentrée.

Historically, women’s fragrances tended to have higher levels of aromatic compounds than men’s fragrances. Fragrances marketed to men were typically sold as EdT or EdC, rarely as EdP or perfume extracts. This is changing in the modern fragrance world, especially as fragrances are becoming more unisex. Women’s fragrances used to be common in all levels of concentration, but today are mainly seen in parfum, EdP and EdT concentrations.^{[citation needed]}

Solvent types

Perfume oils are often diluted with a solvent, though this is not always the case, and its necessity is disputed. By far the most common solvent for perfume-oil dilution is alcohol, typically a mixture of ethanol and water or a rectified spirit. Perfume oil can also be diluted by means of neutral-smelling oils such as fractionated coconut oil, or liquid waxes such as jojoba oil.

Applying fragrances

The conventional application of pure perfume (parfum extrait) in Western cultures is at pulse points, such as behind the ears, the nape of the neck, and the insides of wrists, elbows and knees, so that the pulse point will warm the perfume and release fragrance continuously. According to perfumer Sophia Grojsman behind the knees is the ideal point to apply perfume in order that the scent may rise.^[27] The modern perfume industry encourages the practice of layering fragrance so that it is released in different intensities depending upon the time of the day. Lightly scented products such as bath oil, shower gel, and body lotion are recommended for the morning; eau de toilette is suggested for the afternoon; and perfume applied to the pulse points for evening.^{[28][self-published source]} Cologne fragrance is released rapidly, lasting around 2 hours. Eau de toilette lasts from 2 to 4 hours, while perfume may last up to six hours.^[29]

A variety of factors can influence how fragrance interacts with the wearer’s own physiology and affect the perception of the fragrance. Diet is one factor, as eating spicy and fatty foods can increase the intensity of a fragrance.^[30] The use of medications can also impact the character of a fragrance.^[30] The relative dryness of the wearer’s skin is important, since dry skin will not hold fragrance as long as skin with more oil.^[29]