Question, How do I find a bridge between accords/bases? AFAIK a bridge is an AC that acts as link between building blocks (bases/accords). But how do I find the right one?
It's not always easy.
This is a big part of the magic of perfumery.
The same phenomena that allows different notes to come together in accord creating a new perception also makes it complicated to combine different accords, because there can be crossover interaction between each of the individual notes in those accords, not always for the better.
In some cases you might even have to break it down into the fundamentals, reexamine the accords and look at the individual components within them. It can certainly take a lot of experimentation. Intuition can certainly be helpful and necessary too, but that takes a huge amount of experience. But in the end, it comes down to experimentation. Trying to find new combinations of accords and notes. It's very normal to take large amounts of inspiration from previously existing formulas.
Sometimes certain ACs can help act is a bridge between two notes, but that is very dependent on the situation. And looking for some AC to bridge together two notes is definitely not a panacea; it shouldn't be the first thing you look to as a solution.
Often the solution is not to add more, but to look at what you can subtract.
Sometimes it can be difficult to put together a large number of different notes or accords together without the overall fragrance starting to become "muddled". Just because you like two notes or accords does not always mean they will combine well together.
Question, How do I find a bridge between accords/bases? AFAIK a bridge is an AC that acts as link between building blocks (bases/accords). But how do I find the right one?
You can ask specifically, and members here might be able to suggest some ACs you could try in that situation.
But to ask that question, you would really have to give a lot of specifics, like what notes you are trying to combine, what exactly you are trying to achieve, even everything that will be in your formula.
It's really hard to give a general answer to that question. There is no simple answer that will cover all, or even most situations.
I have noticed that there's a tendency for notes and accords to work in triads. So sometimes if two things are not going together, you can think what other notes are you aware of that might go well with both those notes.
In some cases you might have to rebuild one of your accords, to be able to allow it get along with the others better. But that can be kind of advanced. For example, it might not be the kind of note that's the problem, but a specific smell from one of the ACs within that note, which is causing the mismatch problem. Keep in mind there are many different types of "rose" notes, several different types of "apple" notes, many different types of "wood" notes, many types of "white florals", so sometimes if a note doesn't seem to be working, you might want to backtrack and find a different variation of that note.
This doesn't have an easy answer.
I do suspect your real problem may not be that you need a bridge but that something in your formula is out of balance. Or that it is lacking something very commonly found in a large percent of formulas.
One method I've seen to help blending is writing your formulas by heart, modifier, blender and fixative; rather than top, middle and base.
Heart - the core scent of the perfume, often in the middle note or an accord (or series of accords) around the theme. e.g. 'Rose' will include an accord of Geraniol, Citronellol, PEA.
Modifiers - think of these like adjectives in a sentence. "Fresh" Rose. Tend to be top notes or very volatile notes. A 'fresh' Rose could contain modifiers of triplal or cis3Hex; a 'spicy' rose - Eugenol; 'sweet' rose - damascone beta, etc.
Blenders - something to blend the heart and modifiers, as well as blender other accords that might sit in the top or base. They fill in the gaps and are well known for their transparency and blending qualities.
These materials include: Linalool, Hedione, Iso E Super, Lyral, Mayol, Bergamot, Lily of Valley, Ionones, Ambrox.
E.g. For a Rose accord (floral) to blend with a Patchouli accord (woody), you might want to use ionones (both floral and woody), Hedione (floral) and/or Iso E Super (woody).
Fixatives - finally to give a 3rd dimension to the perfume, add a fixative. They have more odour-life and more depth. They also help fix the perfume better to the skin. The best example here are Musks, but also could be vanilla or Sandalwoods. These are good to help increase the perfume's dimension and longevity but too much can make it flat. Fixatives tend to be base notes and ideally should have something in common with the heart theme. E.g. if the heart is rose, the fixative might be a musk accord of ethylene brassylate (skin), muscenone (animalic) and galaxolide (clean) to give it a sensual dimension.
And there, on paper, you have a complete formula.
Not saying this is the best system, but it's one I've seen and have used myself a few times to ideate a formula. In GCMS, you start to notice that materials with the highest percentage tend to be fixatives and blenders (musk's, Ambrox, iso E, linalool, hedione, ionones, etc.) Largely because of their transparency/blending qualities and ability to increase perfume longevity/fixing.
A good answer to your question requires a thorough knowledge of the ingredients you are using. Both the evaporation rate, and the odour types. Petitgrain oil was mentioned in a post above, as a good link between top and middle notes. Knowing the smell of Petitgrain will help you to decide which top and middle notes can best be bridged using Petitgrain. Other building block type ingredients will be used in a similar way.
Getting to know your materials involves a lot of experimentation so that you can find out what ingredients will do the job that you want. I'm afraid there is no quick answer.
Nice, nice. If I understand this right a bridge is a material that has some smell in common with the side(s) it's supposed to link to. Either with one of the sides, in best case with both sides. Moreover than that, a bridge has to be transparent enough to not distract from the main notes. Is that correct? And, is 'blender' another name for 'bridge' then?
I'm not familiar with the term 'bridge' in perfumery, but I don't see why it can't be viewed the same as 'blender'. The transparency is key, you want something that connects the perfume overall as different molecules evaporate at different rates. If the scent is overall floral, a combination of Linalool, PEA and Hedione or Ionones are helpful blenders because they are commonly present in common floral notes and accords and therefore are good 'bridges' to the next note as the first dries down. E.g. in a fougere, linalool is present in both bergamot and lavender, but bergamot evaporates quicker than lavender, so Linalool would be a good way to blend the two notes together even though they evaporate at different rates, keeping then transition smooth.
