- Composition. As a crude rule, alcohol based perfumes will boost projection, but will also last for less time. Oil is the opposite. Eau de toilettes are alcohol heavy while Parfum/attars are oil heavy.
- Despite all of this, the manufacturer can add compounds that change basically anything. They can make an oil perfume project or an alcohol perfume not project. They can blend quieter ingredients into strong perfumes and vice versa. Designer perfumes do a lot of this monkey business.
- Type of skin/weather. Different types of skin and the humidity of the air affect different perfumes in different ways.
If your goal is a quieter affair, middle grounds like lemongrass(not so projecting)+eau de toilette(alcohol) can work pretty well. 100% Khus oil on warm skin also works a treat. Iris perfumes are typically used in composition with a lot of other stuff, so you really gotta try them out and find out which one works for you.
