In playing with thermochromic ink, I noticed the black pigment disappeared and never came back after drying it with the heat gun. To reset the color, I had to put it in the kitchen fridge. Perhaps the threshold is too low for this setting.
In playing with thermochromic ink, I noticed the black pigment disappeared and never came back after drying it with the heat gun. To reset the color, I had to put it in the kitchen fridge. Perhaps the threshold is too low for this setting.