[evincarofautumn]

My working model for why colours admit description more readily than smells is that we judge and decompose them in largely the same way, but it’s simply easier to develop a repertoire of colours. They’re everywhere, most people have decent colour vision, and someone can point to them and tell you what they are in relative isolation.

Whereas smells (and tastes) are much more diverse, and rarely pure, isolated chemicals but more often complex profiles of many different compounds.

A common way that people develop a repertoire of smells is through cooking: now that I have some experience with many different ingredients and styles, I can now readily tell what went into a dish and how I might replicate it, describe new tastes in terms of old ones, and imagine new flavour combinations and how they would work together.

Chemistry offers another angle—if you know what I mean by “indolic” then you can probably conjure a mental image of exactly the heavy musk I’m referring to, but you probably have no clue if you haven’t experienced it and been told that that’s what you’re experiencing. You can add specific chemicals to your repertoire of smells.

A similar thing seems to hold for recreational drug experiences. If someone has had many different drugs before, especially drugs with similar pharmacodynamics that operate on the same receptors, it’s relatively easy to give them the gist of what something is going to feel like by reference to similar experiences. If they haven’t, there’s only so much you can do to prepare them for what is going to be a novel experience.

[GuiA]

Perhaps I'm simplifying/abstracting a bit too much here but - colors are single dimensional (i.e. the wavelength of the light you're seeing) whereas smells are multidimensional/maybe not even really mappable to any continuum.

[pygy_]

Colors are not wavelength. Color actually has three dimensions that can be coded as RGB, HSL, LAB, or using degenerate coding in four dimensions with CYMK.

Visual geometry has three dimensions, making vision a 6 dimensions thing (plus time, but that is added to every sense).

You point still stands though, since AFAIK smell has many more dimensions (not sure if they've been thoroughly counted).

[GolDDranks]

Actually, color sensation is three dimensional because we have three types of cells that are sensitive to different frequencies.

One could maybe argue that the dimensionality of a smell sensation corresponds to the amount of types of receptors we have in our noses.

[red75prime]

> colors are single dimensional

Light is a mixture of different wavelengths, so, in a sense, it's infinitely dimensional. People's perception of light is usually three dimensional.

> maybe not even really mappable to any continuum

I think it cannot be continuum, as sense of smell is caused by discrete molecules. As for "not mappable", it can be that it's mappable, but our brain is really bad at it.

[amelius]

But light is composed of photons, which carry a certain energy which is responsible for the color you see.

[scatters]

Pinks and purples are non-spectral, mixing red and blue. Browns are unsaturated, dark oranges. Greys contain all wavelengths.