# 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](/survey-of-alternative-displays/experimental-other/electrochromic-paint.md) ### 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](/survey-of-alternative-displays/alternative-displays/laser-projectors.md#lasers-and-photosensitive-surfaces). {% embed url="" %} ### 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. 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="" %} 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="" %} ### 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. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://blair-neal.gitbook.io/survey-of-alternative-displays/experimental-other/light-activated-and-other-reactive-surfaces-and-materials.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.