The video does not use any special effects. Your warm breath fades the ink to transparent; cool air darkens it producing a moving effect. What you see is what you'll get: A little practice goes a long way...
The effect is most apparent in temperatures around 70 degrees Fahrenheit or lower, as you need warm/cool air to activate the shift. I've seen some people carry around a damp sponge or napkin and subtly wipe their mask to keep it moist - it reacts to subtle breaths better in that state. Also, if you own two or more masks, you can secretly slip off and switch faces and keep the effect "new" for the people around you.
The mask is a custom stretch spandex-blend hood machine-seamed to fit most heads. For measurement's sake, around the forehead is 22" to 24" inches. But using 4-way stretch fabric allows the mask to fit most people comfortably. It has been sewn to provide a snug fit, yet still be durable for stretching.
The fabric has been selected after several months of initial testing to provide adequate visibility while still concealing your facial features (eyes, nose, hair). There is no need for eyeholes as the fabric stretches and the weave allows the wearer to see comfortably through the mask. As for breathing, no concerns either. Although, practicing how to maneuver your breath in different directions will only help the effect. Example: blowing warm air upwards towards your nose will trigger the morph higher in the midface.
I heat-set the ink, so the effect is permanent and moisture-proof. However because the fabric is a fine (and expensive) spandex blend, machine washing/drying is not recommended. Just use a damp sponge to dab the spots you wish to clean.
For Halloween, costume parties, cosplay, comic book conventions, movie roles, fantasy play or for fighting crime (no really, don't). People don't always need a reason is what we've found. Some people just like to wear creepy, scary, cool costumes and masks. We don't judge.
Each is hand-dyed with splotchy, jagged-edge inkblots so slight differences may occur. There is an art to get the moving simulation effect, and ink dispersion and fading is key. The crisp lines indicative of silk-screening, although an easier printing method, just look too clean, mass-produced and flat-out generic.
I'm not sure. But I am a professional graphic artist who knows the subtleties of ink gradients and their factor in making the ink transition appear effective and realistic. Also, I was the original seller of these masks on Ebay more than 9 years ago. I've not only designed, but perfected the technique.