Use Color-Changing Alginate like a Pro

Use Color-Changing Alginate like a Pro

Posted by Chris Baker (Dr. Alginate on May 16th 2018

Our BabyGel (380) Alginate is our number 1 seller. Our customers love it. Here is what I know about it.


About 10 years ago a good customer of ours asked me to make a "Color-Changing" alginate.  I had seen color-changing dental alginates but I thought they were just a gimmick. He was a really great customer so I decided to tackle the challenge.


I put on my mad scientist hat and pretty quickly figured out the chemistry involved. Using a tiny bit of a very safe pH indicating dye (phenolphthalein) and by adjusting the pH (alkaline/acid) balance, I could get the alginate to fade from pink to white whenever I wanted.

We decided that a perfect use for this new formula was for baby and child hand casting, so we settled on:

  • Setting time of 3 minutes w/80°F water
  • "Fade-to-White" time of 2:15 w/80°F water

Baby Hand Casting

Since the setting time of an alginate is dependent on the water temperature used (warmer=faster), we found that this new formula (380) worked really well for infants by using even warmer water. 

The main problem making hand molds of babies and children is that they tend to wiggle around during the procedure. Older children are difficult to distract and can be frightened because they don't understand why they have their hand in a "scary bucket of goo".

The best solution turned out to make the alginate the same temperature as their skin. The skin temperature of an average baby hand is 91° to 92°F. By mixing the alginate with 95°F water, the alginate cools during mixing yielding a finished mix that is the perfect temperature.

If the child is asleep during the procedure, they almost never wake up before it is done. If they are awake, they are much easier to distract because they can hardly feel the warm alginate on their hand.

When mixing the BabyGel (380) alginate with 95°F water we get:

  • Setting time between 2:00 and 2:15
  • "Fade-to-White" time between 1:30 and 1:40.

Once the hand is submerged in the alginate it begins to set very quickly thereafter, limiting the amount of time they have to be "in". This also minimizes the amount of time they have to ruin the mold by being too active.

Turns out that the "Color-Changing" thing was much more than just a gimmick.

Do you have experience with BabyGel (380), or ideas about how to use it? Email us at

#colorchangingalginate #babyhandalginate