REVIEW: Color Changing Pigment Salts Postcard Set from Boulder Colors

A few weeks ago, I reviewed watercolors from Boulder Colors that were made from food waste, flowers, plants and other natural sources. Boulder Colors also makes pigment salts — fun tins of powder that change color, expanding and turning into different colors when dropped onto wet paper.

These are plant-based pH sensitive pigment powders, combined salt, and household safe chemical modifiers.

Ingredients: Red cabbage, radish skin, butterfly pea flower, hibiscus, rose, washing soda, citric acid, and salt. Non-edible.

You may have noticed that I called this an introduction rather than a review.

When I asked Amanda Fan of Boulder Colors a few questions for my previous review, of their watercolors, she asked, “Have you tried our pigment salts yet? I just changed the recipe and have a few of the older versions left that I won’t be selling if you’d like to try: they still work but might need a good grind first if you live somewhere super humid. Maybe add some rice to help with moisture.. the new recipe solves all this thankfully, just wanted to give you a heads up.”

I don’t live anywhere super-humid, but the powders did have solidified clumps.  I used a spoon to grind them down, which you can see in the photo above this one.

Since there is a new formulation, I don’t know for sure that it would act exactly the same as the pigment salts I have.  I think they’ll act similarly.

So this introduction will give you an idea of what you might expect but there could be differences.

Boulder Colors makes their products in small batches, and there may be different colors and different postcards available at any given time.

The Colors

Each color of the Pigment Salts turns into two or three different colors.

There’s a little bit of a learning curve before you get the right ratio of water and pigment. isn’t that the story of watercolor in a nutshell?

If you use too much water, the colors all blend into one.  If you don’t use enough water, the powder clumps, and doesn’t dissolve completely.  You can vary the amount of water to get more or less separation of color.  The pigment salts leave a slightly gritty texture. Some of the powder may be left undissolved, and can be gently brushed off after the paint has thoroughly dried. 

A little of the powder goes a long way, but some of the colors dissolve and/or disperse more easily than the others.

While the new formulation could mean the ratio needed is different than mine, I’m certain you’ll still need to play a little to get the results you want. Fortunately, a little of the powder goes a long way and the playing around is half the fun!

Go with the flow, and let these pigments do their own thang, and you’ll get the best results.

The set included two sheets of information and instructions.

The most common way to use the pigment salts is to put a wash of clean water on the paper, then drop in the salts.  I used this method for the color chart, and then tried a few other methods on some of the postcards.

The Postcards

Unfortunately, I forgot to scan all six of the postcards that came in the kit before painting on them.  Too eager to start playing, lol!

The back of the postcards has lines for an address, and room for a short message.


The ghostly black figure is all that is on the original postcard.  I wet the card at random and sprinkled on some of the Hibiscus. When that dried, I rewet and sprinkled on some Red Cabbage to see what would happen.

Would it all blend together or show through or just wash away when I wet it?

The Red Cabbage pretty much covered most of the Pink Rose.  It became more opaque and expanded more so there was no white showing. Better to pick one pigment salt and only use one layer. Good to know.

I decided on a second test. As I mentioned earlier, the pigment salts can leave a gritty texture and I wondered if it would be possible to draw on it. I used a black technical pen (nylon tip) and a white gel pen.

There was no trouble with the white, but the black pen kept clogging.  I had to scribble on a piece of scratch paper to clean it. It did start up again several times, but I would hesitate to use it regularly this way because I’m sure it would be ruined before long. Also, good to know!

This postcard has an ink drawing of a dragon.  I used Radish for the fire and Pink Rose for the dragon.  You can see that the pigment salt is pretty transparent with just a single wash.

My test here was to see how well I could control the pigment salt. Earlier tests for creating the chart showed me that Radish dispersed the most wildly, and kept the most intense color. Pink Rose dispersed the least, and had the least intense color. This made them the best choices for what I wanted.

 I only wet the portion where I wanted color, and that’s exactly where the color went.   

For the next postcard, I decided to see what would happen if I used these salts like regular watercolor. I was pretty sure the colors would run together, but I’ve been surprised before.  I put a thin layer of powder at the bottom of the pan and covered it with water.  I didn’t expect the reaction but it was kind of fun watching the pigments bubble up, though I worried they might bubble over.  They didn’t, and settled down after a few minutes.

The colors did blend into one, though a few hints of the secondary colors pop up here and there.  You get some granulation and I like the colors.  While it sort goes against the purpose of the pigment salts, it’s good to know you can get solid colors if you decide you need some.

I decided to try for something in between. I wet the face, dropped in Butterfly Pea Flower, and let it dry.  I repeated this with Pink Rose for the hair and shadows on the face, and then repeated again with Red Cabbage for the coat.

But this time, as the color dried, I kept moving the powder around, adding more powder for more intense color, carefully adding more water until the powder was all dissolved. This blended the color more than just letting it sit and spread out on its own, while leaving random pops of color. 

I didn’t have a color that really suited skin tones, so my gentleman is a rather elegant Zombie!


I think these pigment salts are a lot of fun. The colors are beautiful and you get something different every time you use them.

You can go for an effect that is wild and unpredictable, or a more controlled look with pops of random color.

While the fun of them is letting them do what they want, you do have some control. You can direct where they will flow by wetting just the area you want colored. You can increase or decrease intensity by the amount of water used. You can control how solid the coverage is by the amount of powder you add, and how much you play with the powder once added.

Tools & Links


I received this postcard set of pigment salts from Boulder Colors for the purpose of this review. I received no other considerations, though this post may contain affiliate links which help support Doodlewash. As always, all opinions expressed are my own.

Recommended3 recommendationsPublished in Art Supply Reviews

16 thoughts on “REVIEW: Color Changing Pigment Salts Postcard Set from Boulder Colors

  1. great review, Sandra, interesting to me. I love working with powders so this caught my eye right away. and . . . I went to their shop. have you looked at their shop? it is awesome! Harry Potter dork that I am loved everything there!

    Sparkling Heart
    • sandra-strait

Leave Me A Comment!

%d bloggers like this: