This is 100g of red thermochromic pigment which changes from red to clear (whatever colour is beneath is revealed) when the tempurature rises over 31 degrees (~= 87F).


this pigment is specifically made in the tempurature range to turn clear on contact with human body heat.

Some applications are the famous Rorschach real moving mask, novelty car paint/ colour changing car, painted clock, mood rings and so much more!

To use on fabric its recomended you use an acrylic transparent base, such as speedball, however, if you dont need the medium to be perticularly flexible and resiliant to stretch and fold induced cracks and flaking, i find that wallpaper glue does the job just fine, for anything that is still, or wont move much. generally though any glue that is clear will function adequately  Also there are some types of acrylic, though water soluble, mediums out there very common at art stores, news agencies and $2 shops.

This pigment can be mixed into water based "acrylic mediums" or mixed into thinned spray laquers like automotive clearcoat. For sheer efficiency of grams per area covered i recommend using automotive clearcoat however.
When storing unused paint, water based will last a long time as it is, but with laquer based paint, try to store it as thick as possible, and also if possible refrigerate. Generally it should hold at any concentration it would reasonably be used at, but especially diluted solutions have a tendancy change irreversibly to white. The pigment is comprised of microencapsulated leuco dyes inside resin, i think that if the capacity of the thinner to dissolve anything is great enough, the resin can soften, causing the pigments thermochromic compounds to properly mix and neutralize themselves (its just a theory). A good rule of thumb is to have unused paint as thick as honey.
Also note, acetone will cause this same effect in any concentration where it is a liquid, within 8 hours, much less depending on the medium used.

Caution should be taken when mixing this pigment, its extremely light and fine, breathing on it can blow it all away quite easily, its also hydrophobic and thus will not mix with water alone. to mix constantly submerge the pigment in the medium, or if possible use a coffee/drink mini mixer / any high speed mixer, and seal the top of the container so pigment does not escape. pigment must be pushed into the medium or nothing will happen. However youll see exactly how this works when you try it for yourself.

A very important note, do not allow the pigment to be exposed to large amounts of ultraviolet radiation, aka direct strong sunlight, without a UV overcoat, this pigment is not a simple elemental pigment like nickle oxide, its a complex hydrocarbon chain, and radiation easily breaks it up.