Universal indicator is a pH indicator that exhibits a full spectrum of colour changes. For this reason it is not ideal for titration work where methyl orange or phenolphthalein are much more commonly used.

Universal Indicator is one of the most commonly used indicators. It is made from a mixture of pH-sensitive dyes to create the spectrum of colours it exhibits across a range of different pH values.

Indicator changes

• In very acidic conditions, universal indicator is red, and in less acidic conditions it is orange or yellow.

• In neutral conditions the indicator appears green.

• In alkaline or basic conditions the colour is blue, and in very basic conditions purple.

Universal Indicator is also the group name for a number of Rephlex Records artists, particularly Richard D. James under the stage names of Martin Tressider and "Tan-09", as well as Mike Dred (aka the Kosmic Kommando ), and Rephlex founder Grant Wilson-Clarage (under the stage name IG-88). They use the name Universal Indicator as a refrence to the signature Acid techno sound found on all the releases. 5 albums were released, and a compilation CD was mixed. All the albums are different colours used on the UI spectrum. For more information, see the Aphex Twin page.