What Are FD&C Dyes and Lakes (and How Do They Differ)? | Hacker News Reader

What Are FD&C Dyes and Lakes (and How Do They Differ)?

madmicas.com

21 pointshammock29 comments

One thing not explained here is what “FD&C” means - it’s Food, Drug and Cosmetic Act. It just means the dye is FDA approved as being safe for humans.

For the headline, "What Are FD&C Dyes ..." I was disappointed to see nothing about what FD&C dyes are (as opposed to a regular dye which I assumed is something like "a chemical that exhibits coloring power when dissolved").

Thought the use of the word "lake" here was interesting. (Of course, not the same as a lake you can swim in):

From French laque (“lacquer”), from Persian لاک‎ (lâk), from Hindi लाख (lākh), from Sanskrit लक्ष (lakṣa, “one hundred thousand”), referring to the number of insects that gather on the trees and make the resin seep out. Doublet of lakh, lac and lacquer.

(https://en.wiktionary.org/wiki/lake#Etymology_4)

In Lower German, Norwegian and Swedish (at least), "lake" means "brine", as in pickling liquid. E.g. "saltlake" means specifically a brine that has a lot of salt. And this again comes from "lake" as in "body of water".

Curious if the etymology that lake is coming via the French "lacquer" is actually the correct one, when the alternative that is coming from proto-Germanic "laki" is much closer to the actual chemical composition and way of preparation of the dye lake?

This page leads to more questions than it answers.

After reading it, I still have no idea what the difference is between a dye and a lake, or why it matters, but now I realize I also don't know what blooming is, whether it matters if a dye is water- or oil-soluble, what tinting by dispersion is (and why it matters if that's different from a dye), or why I should care about "dye load". Since those all seem to be involved in the answer to the main question.

Maybe there's a better page to submit to HN on this topic, because this one seems awfully confusing.

Are you reading the same article? Literally all the questions you ask are answered, clearly, in the article, with perhaps an exception to some of the "why it matters" questions. If you see the "about" page for this company you can see that their colorants are for things like bath bombs, soaps, makeup, etc., and so you'd want different things depending on what you're trying to color (e.g. if you're coloring an oil/fat vs. water in a bath).

Literally the second sentence is:

> Dyes must be "bloomed" before use.

It does not define blooming. I still have no idea what that means.

Maybe if you're an expert in this stuff already then it all makes sense. But I'm already lost when it starts by talking about blooming -- and then once it gets to aluminum salts, and strongly emphasizing that it's not elemental aluminum (which matters to the reader why...?), I realize that this is not written for the layperson.

Context clues tell me "blooming" probably means "putting it in water and letting it dissolve", but that's just my guess. It would be nice if they defined it.

The article doesn't make this very clear and the way it phrases it is confusing.

> Dyes must be "bloomed" before use. In their unbloomed state (i.e. in the jar) they are different color than in use.

With the evident meaning: "bloomed" -> out of the jar, in the water.

But blooming means precipitating the dye in whatever solution it will be in, usually using a salt like sodium bicarbonate.

[EDIT] The Wiki page on lakes makes it clearer: https://en.wikipedia.org/wiki/Lake_pigment

The paragraph is this:

> Dyes must be "bloomed" before use. In their unbloomed state (i.e. in the jar) they are different color than in use. For example, our Bright Green Dye is brown in the jar, then turns a vibrant bright green when bloomed in water.

It does a pretty good job, together with the rest of the article, explaining that blooming means letting it dissolve in water, at which point the color changes.

I'm not familiar with dyeing at all, but "blooming" is used in a bunch of other contexts that mean similar things, e.g. "coffee blooming" (adding water to freshly ground coffee), even things like "algae blooms".

After reading multiple comments here, I decided to look it up, and discovered:

> Blooming is the process of adding your bath bomb dye to hot water and mixing it with sodium bicarbonate

So no, it's not just dissolving it in water. It's dissolving it in hot water and adding an additional totally separate chemical.

So no, the article does not do a "pretty good job" at explaining. It doesn't explain any of that.

OK, you're right, I apologize and take back what I said. Wouldn't have assumed at all from that description that blooming means adding a base.

One of their dyes is yellow as a powder, but it reacts with lye water when making soap so that it turns a bright orange. Once the saponifying process is completed, the orange comes back to the expected yellow. Very unnerving process when you failed to read that part of the product listing. I also happened to use it for the first time with a fragrance that super accelerated, so it was a double whammy of a disappointing feeling. So at least the fact it turned back to yellow made the batch less disappointing.

>for this company you can see that their colorants are for things like bath bombs, soaps, makeup, etc.

I can highly recommend Mad Micas. It's one of my favorite vendors in this space. Super friendly with hand written thank yous for every purchase.

> whether it matters if a dye is water- or oil-soluble

"Dyes are water soluble, and will not mix with oils."

> what the difference is between a dye and a lake

"Lakes are produced by coloring an aluminum salt... substrate using FD&C dyes."

So a dye is soluble material; lakes are an insoluble material colored with dyes.

> tinting by dispersion is

Lakes disperse in the liquid; dyes dissolve into it. Presumably if you're interested in actually using dyes, this is a distinction you're already familiar with.

> why I should care about "dye load"

"Remember: in general, the higher the dye load, the less you'll need to achieve the color you're going for. Don't make the mistake of comparing a 70% dye load product to one with a 90% dye load."

Alright, but it didn't explain what an FD&C dye was...

First paragraph:

What's A Dye? A dye is a chemical that exhibits coloring power when dissolved. Dyes are water soluble, and will not mix with oils.

Exactly. It's talking about general dyes, while the title names a (presumably) specific sort of dye, an "FD&C" dye. Are all dyes FD&C dyes? What does FD&C mean? Those are not questions answerable by someone who read this article without further research.

All articles presume that the audience has some knowledge going in, but I have no explanation for why dye needs definition but the even more specific FD&C dye doesn't. (shrug)

That doesn't explain what an FD&C dye is unless you already know what FD&C stands for.

If you're shopping at Mad Micas, you probably are.

This is like someone typically that shops at Mad Mica coming to a site you are probably more custom to using and asking what LLM, CNN, etc means. A lot of the articles I've seen about the topic just naturally assume the reader already has some context and just uses acronyms without ever spelling it out nor even attempting to define on a ELI5 kind of a situation which for some reason you are expecting this site to do for you

A lot of people on this thread revealing they can't read "in context" and are upset if every term used doesn't have a footnote.

I guess all the people complaining would prefer lawyer speak:

"FD&C¹ dyes (hearinafter known as DYES)"

¹ FD&C the U.S.² act governing (and defining) the regulation of food, drugs and cosmetics. This act is enforced by the FDA.

² The United States Of America

Addendum: This article is about how the FD&C (as an Act) defines a dye vs a lake.

What's a FDA? :-)

The title promises that the article is going to explain "FD&C Dyes and Lakes"

That's three words, and I expect all three to be defined. I think that's a pretty reasonable request, not an inability to handle context or a desire for lawyer speak.

Context doesn't help explain FD&C at all. It's only in the body of the article once, and it could easily be a technical term.

(Not) fun fact that I learned recently is some dyes like Red 40 are made from petroleum!

https://en.wikipedia.org/wiki/Red#:~:text=The%20most%20commo...

Why is this not a fun fact? Guess I shouldn't let you know where petroleum jelly comes from...

You realize, I hope, that all plastics are also petroleum products.

(except plastics which are not, like PLA)

The majority of flavors, fragrances, medications, and synthesized organic chemicals of all purposes use petroleum as a precursor at some stage of their manufacture.

It's a very cheap source of hydrocarbons and doesn't at all mean there is petroleum in the product.

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