Bromthymol blue (IMAGE) Linköping University Caption To make the wound dressing show the elevated pH value, the researchers used bromthymol blue, BTB, a dye that changes colour from yellow to blue when the pH value exceeds 7. Credit Olov Planthaber Usage Restrictions The contents may be downloaded, used and shared in media channels by, for example, journalists, bloggers, writers, pundits, etc., for purposes of communication, description and commenting on your press release, post or information, on the condition that the contents are used unchanged and in their entirety. The creator must be specified to the extent and in the manner required by good publishing practice (which means, among other things, that the photographer of any photographs must nearly always be specified). License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.