Heather Ackroyd and Dan Harvey have collaborated since 1990. "After observing the pale outline created by a ladder left on a lawn for a few days, the duo decided to make sod into a photographic medium."[7]

Heather Ackroyd's has worked in sculpture, visual and performance art. Multidisciplinary work with focus on processes of growth and transformation, striving to articulate a relationship between performance and visual art.[1] Dan Harvey has worked primarily in sculpture since 1980 and often uses found objects where the effects of nature can be seen. He places these within "intimate tableaux of implied narratives to do with transience, alchemy and decay. " Slate is a principle material in much of his work. The scale moves from very small intimate pieces to large landscape designs.[1]

Their collaborative work includes installation, sculpture, landscape design, photography, performance, film and frequently reflects both architectural and scientific concerns. Another conceptual focus is time and visibility.[4]

"In the greater body of our artwork we play with many materials exploring processes of growth, transformation and decay, and we embrace the transience and ephemeral nature of our materials. Yet somehow the fragility of these chlorophyll apparitions urged us to make moves to preserve them longer."
 
"We can't recall the precise moment when we first articulated this desire to hold the image - conceptually, we can rationalise the move to preserve the photographic grass image for longer by saying it follows through the established process of photography of exposing, developing and then fixing the image."
 
"To talk about 'fixing' an image refers directly to the photographic process of stabilising the emergent picture. It is a word used as much now, as nearly 200 years ago, by the early pioneers of photography such as, Thomas Wedgewood, Humphrey Davy, Fox Talbot, the Niepce brothers, Daguerre, and Bayard, to name but a few. "

Extracts from a lecture delivered by the artists through The Royal Society in conjunction with the Creating Sparks Festival, September 2001 http://www.artsadmin.co.uk/artists/ah/photosynthesistext.html#Living%20Skins

• The photosensitive surface is a living mini-lawn
• It is placed in a giant darkroom
• The mini-lawn is exposed light of a 400-W projector bulb passing through a negative for prolonged periods
• The varying densities of the negative's lighter and darker areas produce a full range of midtones by controlling the light levels in each area.
• The light produces green, or darker tones, lack of light produces lighter (yellow) tones
• In 1997, the artists began a collaboration with IGER scientists, Prof Howard Thomas and Dr Helen Ougham, who are studying the biochemistry behind how chlorophyll breaks down when leaves start to age and turn yellow. (IGER = Institute of Grassland and Environmental Research, Aberystwyth,UK). This process has both an economic and cultural significance as it is resonsible for the making crops less productive and for the colors seen at the changing of the seasons. [5]
• They are collaborating on the further development of a stay-green variety of grass that had been known since the 1960s.
• The scientists have modified the expression of the genes responsible for the senescence of the green leaves, resisting the tendency to yellow. 
• The application of this grass in the artist's work has significantly retained the visibility of the image and in response to their collaboration the scientists have developed methods for non-invasive analysis of events going on in the cells of senescing leaf tissue, through the use of hyper-spectral imaging technology. [4].
• This is an example of a collaboration where the artists are changing the way the scientists work. A recent quote:

  “We were all dumbstruck when we saw it — such colors and textures,” says Helen Ougham, a biochemist at IGER. “We’re not used to looking at grass growing, like they do, on a canvas. We started thinking about what images can tell us.”
       Usually researchers grind plants up and extract pigments in order to study them. But they lose all of the variations in the plant, both over time and over the surface of the leaves, and destroy the plants in the process.
       Inspired by Ackroyd and Harvey’s work, the Wales team developed a new imaging technique that monitors pigment levels without damaging plants. Still in the developmental stages, the technique could some day be used to quickly scan plants and learn about their health.
       “We wouldn’t be doing what we’re doing now if it weren’t for [Ackroyd and Harvey],” says Ougham.[5]