Photography is the new spectrometry


Data equivalent to multiple emission spectra extracted from a single photograph

Many researchers use photographs of fluorescent solutions to illustrate their scientific papers but scientists in Germany have shown these photographs are more than just pictures and actually contain valuable information.

Emission spectroscopy is considered the gold standard for characterising fluorescent solutions but analysing this data can be time consuming and non-intuitive, especially when a lot of data is involved. This led Uwe Bunz’s team at Heidelberg University to ask if photography might be a better method for obtaining this information quickly and efficiently. And the answer is yes.

Photographic and spectroscopic data can be compared using the chromaticity coordinates, r,g. These can be easily extracted from emission spectra using colour matching functions. However, in order to extract chromaticity coordinates from photographs, we have to assume that the camera is using the same set of functions. ‘There was no good way to compare information gleaned from emission spectra and photographs,’ explains Bunz.

To get around this problem Bunz’s team used pseudo colour matching functions to give chromaticity coordinates specific to their camera. These values can then be directly compared to r,g values from emission spectra, converting the camera into a three filter detector. ‘We can now interconvert fluorescence spectral data and colour information gleaned from photographs,’ says Bunz. ‘The common denominators are the chromaticity coordinates r,g.’

They tested their method on light emitting diodes (LEDs) and solutions of inorganic quantum dots and organic fluorescent dyes. In all three cases, the photo-extracted coordinates were excellent matches with the spectroscopic values.

‘It’s a very simple but very effective method for analysing fast chemical processes,’ says Manijeh Razeghi, an expert in using cameras for spectroscopy from Northwestern University in Evanston, Illinois, US. ‘Its simplicity allows it to be used by a wide variety of people with different levels of knowledge about spectroscopy.’

Repurposing a camera as a spectrometer may sound a little unorthodox but a single photograph can simultaneously capture data on multiple coloured solutions making it cheap and efficient. Its applications range from the analysis of quality control test trips to adulterations of medical drugs.


Related Content

Fluorescence, camera, action

9 November 2012 Research

news image

Analysing fluorescence responses using digital photography

Raising a glass to champagne

1 June 2012 Feature

news image

Andy Extance uncorks the secrets of sparkling wines’ unique taste and aroma

Most Commented

How to print a crystal in 3D

17 April 2014 Research

news image

Rather than looking at a crystal on a screen, print it out and hold it in your hand

The sultan of synthesis

11 April 2014 Feature

news image

Phil Baran is spurring organic chemists to rethink how they make complex compounds, as Mark Peplow discovers