Questions on coloring bath bombs are among the most common concerns in the bath bomb community. The debate over lakes, dyes, micas, and how and when to use these products seems to get no end of attention. If I had to choose the most elusive and highly sought after color it would be BLACK. 

That’s right. Black. I said it. 

To me, nothing is sexier, or more mysterious than a jet black bath bomb that gives me inky black water. Don’t get me wrong, I know it’s not for everyone. I know some of you are sitting there perfectly happy with your pastel pinks and baby blues, and if that’s the case, more power to you. But, if you have been searching for the perfect black mix, then let me share with you 5 different ways to make black, including my very own favorite blend! This midnight special makes the deepest, darkest, blackest bath bombs! And the best part is, there is zero staining with this mix!

(Do you want to see me mix these together and have a deeper conversation about black bath bombs and colorants to get these colors? Mixing Black Bath Bomb Colors is a bonus to our Bubbles for Dad Mini-Bootcamp! You can grab it here.)


Now the question of color is an age old one. In fact, in A Study in Purple I talked about additive and subtractive color. I discussed how additive coloring works within a system based on light, and Subtractive coloring works within a system of pigments and dyes.  

In subtractive coloring you start with a white base and the colorants SUBTRACT some of the whiteness that is being reflected and sent to your eye. Basically, any solid object you see is using some form of Subtractive coloring.

What’s interesting is that in an Additive (Light based) system all the colors mixed together create white light. But in a Subtractive (Dye & Pigment based) system, all the colors mix together to create black! Theoretically then, you simply mix a bunch of colors up and get black right? Well. Kind of. 

Here’s the deal. Light and Dark don’t fall into neat little categories like that. Don’t believe me? You’ve obviously never spent hours debating over hundreds of white paint samples that all manage to look completely different. Or, as an artist one of the most important things I had to learn was that white and black were a range of colors mixed together. The whites of the eyes are actually blue, with some pink and yellow thrown in the mix. The shadow under a leaf isn’t solid black, instead it is usually shades of green, blues, and yellows mixed in. In fact, if you start to take a look around you’ll begin to see that there is always a range. All the colors are work together to create a spectrum.  

Even the designation of human skin as black or white is totally misleading. People come in a whole range of skin tones, and I have never seen a milk white human or jet black one. We are all a beautiful mix, from peachy pale to rich warm chocolate. In skin, melanin is the primary pigment responsible for producing brown tones, but there are also blues, greens, and reds at work. Together they account for the unique variety that make up the human family. 

In bath bombs, we use lakes or dyes to create that range!

Our darkest, boldest bath bomb can be achieved by blending all the colors together, but the balance of that blend will dictate the tones present in the end result. Have you ever purchased a pre-made Lake or dye that was supposed to be black, only for it to look maroon either in your mix, or worse still in the water? Or what about a mix that looked green? Yep. It happens. 

Well, here’s how to mix your own black! It’s so much cheaper in the long run if you can learn to mix your own colors. Don’t get me wrong, I have pre-mixed colors that I occasionally use, but as I’m about to show you, they won’t be perfect and you still might need to tweak them to get your desired tone. The cost savings always brings me back to my old faithful Blue 1, Red 40 & 27, and Yellow 5 & 6. They never fail me. I prefer to use high quality Lakes that yield amazing color payout! Lakes are super easy to tweak, cost effective, and when they come from a trusted supplier, they can give you beautifully colored water!


Polysorbate 80 is an emulsifying agent that allows the water in the bath tub and the oils in your bath fizzy to incorporate. Instead of the oils floating on top, they will become fully suspended in the water! Since Lakes are oil soluble, they also will not disperse in the water unless you add Poly 80. Instead they will cling to the oils if they can find them, or simply float on top of the water and create a huge mess. So, if you use Lake colorants in bath bombs then you must use Poly 80! You must must must do this!  

I like to get my lakes from (affiliate link)


To test the colors I started with a basic bath bomb mix and weighed out 250g for each colorant. Now the amounts I use here are quite small, so to color a full size batch you’ll need to up your portions, however the ratios will remain consistent! 

BLACK 1: First I tested Celestial Splendor Lake from Saraphina’s Coastal Colours. To get a decent black tone (I would have preferred a bit darker) I used 1 tsp.

BLACK 2: Second I used Obsidian Lake from Saraphina’s Coastal Colours. It has a fairly red tone to it, but I did like how rich the color was. That was also used at 1 tsp.

BLACK 3: Third I used equal parts Yellow 6, Blue 1, Red 40. The color was good. A nice full black with a slight bluish tint. I used these at ¼ tsp each.

BLACK 4: Fourth I used equal parts Yellow 6, Yellow 5, Blue 1, and Red 40. This had a slight green tone to it. I used these at ¼ tsp each.

BLACK 5: Finally, my favorite black blend of all time, a little bit of everything! I use a 2:2:1:1:1 ratio… or

2 parts Red 40, 2 parts Blue 1, 1 part Yellow 5, 1 part Yellow 6, 1 part Red 27. To me, this is the richest, darkest black you can make! I’ve tried several versions where I leave a yellow out, for example, but I always feel like it needs that extra little bit. For this I used ¼ tsp each for Red 40 and Blue 1, and ⅛ tsp each of Yellow 5, Yellow 6, and Red 27.

Here they are all together.


When it was all said and done I gave them each a try in a tub of water. You can see the different tonalities much better like this, especially since they are all in there together.

Here is my favorite blend used in a bath bomb!


“Wait!” I hear you asking, “couldn’t you just use activated charcoal or black oxide? Or even mica?”

Please. Don’t. Charcoal doesn’t wash out or rinse cleanly. Just to show you, I added ¼ tsp of activated charcoal to some left over black mix. Even though the first pan had 5 different bath bomb samples it didn’t stain or leave residue in the tub.

Below, is the lake mix poured out of the tub. No stain or residue.

The charcoal sample, with much less mix over all, left reside and stained the tub.

Below, you can see how the charcoal was just messy! You don’t want a customer to use a charcoal bath bomb and then have to deep-clean their bath tub.

Below, is a side-by-side comparison. The lake blend is on the left and the charcoal is on the right.

Now I understand that this is a porous plastic tub, and most people will have a nice glossy bathtub, but can you be sure? My house is very old and the tub needs to be resurfaced. It gets stains at the drop of a hat and I’m sure it would love to suck up all that charcoal if I ever gave it a chance. This is just a little side test I did when I was cleaning up, but I hope you see why charcoal probably isn’t the best option and I always advise staying away from it. In my experience even black mica can stain, so it’s something I seriously try to avoid! To be sure, make sure you always test your products, and using a plastic tub like this is a great way to do that! You know, just in case your customer’s bathtub is 80 years old like mine!

Don’t forget to sign up for Bubbles for Dad Mini-Bootcamp to get the bonus Mixing Black Bath Bomb Colors!

Authors Note:

I would be remiss if I didn’t admit that skin color weighed heavily on me as I wrote this. If you’re reading this in the archives, George Floyd was killed on May 25th. It has been just over a week. This has been the hardest article to write, even though it’s just about bath bombs. Because it’s not just about bath bombs. It’s about the need for change. The need to find a better way. The need for understanding. It’s about saying that black is beautiful. That black is everything. It’s about learning, listening, and loving. To the black community I want to thank you for the beauty and strength you have shared with the world. For the ways you have enriched our culture with music, dance, food, art, strength, and beauty. Without you we would not be who we are. Thank you. #BLACKLIVESMATTER

About Robyn French Smith

My name is Robyn French Smith! I studied fine art at the University of St Thomas and the Glassell School of Art in Houston TX, and graphic design at The Art Institute of Houston. I started dabbling in DIY bath and body products over 10 years ago after moving to Alaska. While I knew how to make basic soap for several years, I didn’t start looking at it as an art form until about 4 years ago when a neck and shoulder injury made it almost impossible for me to draw and paint. I needed a place for all that creativity to go, and I found it in soap. I received my Basic Soapmaker Certification from the HSCG in 2019 and plan on pursuing further levels of certification.

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