# Light activated and other Reactive Surfaces and Materials

This is a placeholder page to discuss various surfaces and materials that interact with light by developing/glowing/etc.

* Photosensitive/Glow in the Dark
* Photochromic
* Thermochromic
* Hydrochromic
* Magnetic field display
* See also: [Electrochromic Paint](https://blair-neal.gitbook.io/survey-of-alternative-displays/experimental-other/electrochromic-paint)

### Photosensitive Display

These are displays that use glow in the dark pigment/ink/vinyl/material and UV lights/LED's to create images that fade over time.

Harvey Moon of MBLabs created [Persistence](http://www.mblabs.org/projects#/persistence/), a piece that uses an array of ultraviolet LED's on a radial arm to draw things on a "glow in the dark" canvas. There is some similar work with Lasers on the [laser projector section](https://blair-neal.gitbook.io/survey-of-alternative-displays/alternative-displays/laser-projectors#lasers-and-photosensitive-surfaces).

{% embed url="<https://youtu.be/IeoKp3sgJsY>" %}

### Photochromic

This is a pigment/ink that can be screenprinted or embedded in other materials like resin/plastic that can be activated by sunlight or bright UV lights/lasers.&#x20;

Example projects and products:

* [Photochromic Ink and Pigment supplier](https://www.sfxc.co.uk/collections/photochromic-pigments)
* [Random International's "Self Portrait" (2010) that uses UV reactive ink to draw on a large surface](https://www.random-international.com/self-portrait-2010)
* [Kohei Nawa's Blue Seed](http://kohei-nawa.net/projects_category/blue-seed/)
  * I personally suspect that Blue Seed uses Photochromic pigment like this project that promises an almost colorless view of the pigment when inert and then changes colors when activated by a UV light source.

{% embed url="<https://www.youtube.com/watch?v=b50E2FoZ4cw&t=90s>" %}
Kohei Nawa's Blue Seed
{% endembed %}

An exploratory video of someone using photochromic elements in plastics and activating them with  UV lasers, UV LED's and sunlight.

{% embed url="<https://youtu.be/_yU_w7YbNQM>" %}

### Thermochromic

These are materials and pigments that change between two color states when a certain amount of heat is applied.

(Examples to come)

### Hydrochromic

These are pigments and other materials that change color when water comes into contact with them but then change back when they eventually dry out.

### Magnetic Field Display

These are essentially slim materials embedded with small magnetic elements that effectively show magnetic fields when a magnet is placed nearby - they are completely analog.