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  1. #1

    Default longevity = strength/sillage

    Alright folks, here's a thesis for you to pick apart.

    When we talk about longevity and sillage, we are talking about 2 aspects of the same thing: volatility. More volatile molecules are liberated into the gas phase more readily, and once in the gas phase, diffuse farther during a given period of time than less volatile molecules.

    Naturally the more volatile molecules will strongly influence the "top notes" of the fragrance since they will evaporate and diffuse quickly, while less volatile molecules will define the base notes that are most perceptible after the top notes are gone. (Of course there's a continuum; the name "heart notes" suggests molecules of comparatively moderate volatility.)

    So the "longevity" of the "note" of a particular molecule is inversely proportional to the "sillage" of that note, since sillage essentially means quick or wide dispersal of perceptible scent. Of course, the initial volume and concentration of the solution can cause any note to be perceptible longer and to diffuse farther at perceptible levels, which is where the "strength" factor comes from in the equation in the thread title.

    There you are. Are you convinced? It's quite possible I've overlooked something, so have at it!

    (Note: As far as theories of olfaction, it doesn't matter whether you subscribe to the more broadly accepted shape theory or the Turing vibration theory or whatever else, so long as you agree molecules are the medium for it.)

  2. #2

    Default Re: longevity = strength/sillage

    Quote Originally Posted by d4
    ...

    So the "longevity" of the "note" of a particular molecule is inversely proportional to the "sillage" of that note, since sillage essentially means quick or wide dispersal of perceptible scent. Of course, the initial volume and concentration of the solution can cause any note to be perceptible longer and to diffuse farther at perceptible levels, which is where the "strength" factor comes from in the equation in the thread title.

    There you are. Are you convinced? It's quite possible I've overlooked something, so have at it!
    I'm not sure I agree with that sentiment re the connection between longevity and sillage. If sillage is defined as the persistence of scent molecules in the air and longevity is the "lasting" factor, I believe there may not be a connection. I'm just not sure if I can expand on why not!

    Definitely something to think about when I'm not hungover from a Christmas party the night before!
    De gustibus non est disputandum

  3. #3

    Default Re: longevity = strength/sillage

    Taking the formula more mathematical than it is probably meant, high strength/high sillage means standard longevity. I'm not sure this holds empirically. That equation is a rough but logical representation of the chemical mechanism anyway, maybe it just fails to incorporate fixatives and other chemical tricks.

  4. #4

    Question Re: longevity = strength/sillage

    Quote Originally Posted by fakepurseninja
    Taking the formula more mathematical than it is probably meant, high strength/high sillage means standard longevity. I'm not sure this holds empirically. That equation is a rough but logical representation of the chemical mechanism anyway, maybe it just fails to incorporate fixatives and other chemical tricks.
    The formula is quasi-mathematical, and is meant only to represent the direct and inverse relationships among the variables. To make it mathematically precise we'd have to choose numerical measures, and depending on those choices, the relationships may not be linear.

    I suspect "fixatives and other chemical tricks" might complicate things, but does anyone know what tricks there are and what effects they have?

  5. #5

    Default Re: longevity = strength/sillage

    Longevity is not inversely proportional to sillage. Volatility is important to sillage, and to longevity, but the perfumer can simply add more essential oils to the mix to make it last longer. You may think that would just make it stronger, but fragrance can only be dispersed into gases and liquids. Example - if you have a cup of essential oil, only the molecules on top will dilute into air, the oil in the rest of the cup has to wait until it is in contact with gases. So, if you have oil on your skin, not all of it is reacting with air.

    Take for example A*Men, strong sillage, lasts a fortnight.
    Opium for Men, EDP lasts longer than the EDT version, and is also stronger. So, it really depends upon the talent of the perfumer, not chemistry equations IMHO.
    - Rich

  6. #6

    Default Re: longevity = strength/sillage

    This thread made me smart!

  7. #7
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    Default Re: longevity = strength/sillage

    Also, consider this: Top notes are "bound" to the perfume by different types of base notes. The interaction of some of these is to bind the top notes and heart notes longer than some others. I think the large number of combinations (remember the factorials in the formula?) will make for a wide variation in the release rates you speak of.

    And then, when you speak of sillage, it might be good to remember that the fragrance being released varies over time, so that the top notes go away first, and the olfactory impression changes over the life of the scent. Sillage varies in strength as the notes are released, but does not always become consistently weaker. Think of scents with patchouli in the base, for example.

    My overall conclusion is that the base notes in the perfume affect the dispersion, and therefore all the elements you speak of.
    Yr good bud,

    JaimeB

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  8. #8

    Default Re: longevity = strength/sillage

    If thats the case, How do you explain the phenomenon of the mighty KOUROS???

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