[HN Gopher] What Are FD&C Dyes and Lakes (and How Do They Differ)?
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What Are FD&C Dyes and Lakes (and How Do They Differ)?
Author : hammock
Score : 17 points
Date : 2023-08-21 15:51 UTC (7 hours ago)
(HTM) web link (www.madmicas.com)
(TXT) w3m dump (www.madmicas.com)
| jlas wrote:
| (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...
| fatbird wrote:
| You realize, I hope, that all plastics are also petroleum
| products.
| Clamchop wrote:
| 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.
| hn_throwaway_99 wrote:
| Why is this not a fun fact? Guess I shouldn't let you know
| where petroleum jelly comes from...
| Dwedit wrote:
| Alright, but it didn't explain what an FD&C dye was...
| djbusby wrote:
| 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.
| margalabargala wrote:
| 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.
| Clamchop wrote:
| 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)
| kwhitefoot wrote:
| That doesn't explain what an FD&C dye is unless you already
| know what FD&C stands for.
| dylan604 wrote:
| 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
| fellowniusmonk wrote:
| 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.
| cvs268 wrote:
| What's a FDA? :-)
| 542458 wrote:
| 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.
| blendergeek wrote:
| 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").
| nielsbot wrote:
| 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 lkh (lak), from Hindi
| laakh (lakh), from Sanskrit lkss (laksa, "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)
| semi-extrinsic wrote:
| 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?
| crazygringo wrote:
| 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.
| fatbird wrote:
| > 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."
| hn_throwaway_99 wrote:
| 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).
| dylan604 wrote:
| >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.
| crazygringo wrote:
| 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.
| hn_throwaway_99 wrote:
| 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".
| crazygringo wrote:
| 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.
| hn_throwaway_99 wrote:
| 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.
| dylan604 wrote:
| 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.
| margalabargala wrote:
| 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.
| eindiran wrote:
| 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
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(page generated 2023-08-21 23:02 UTC)