I’ve just begun work on a new painting. I’ve been thinking about the colours I want to use for a few days, dissecting out the colour the light microscope casts on all cell populations, indiscriminately. I squeezed fresh paint from a selection of paint tubes, and this is what I produced. This is a method of working I’ve been using for a long time, and it’s been a while since I’ve thought about what I am doing.
I have always been interested and attracted to colour: for me, drawing and painting is a process of exploring the relationships between colours as well as forms. This may be one of the reasons I was so drawn to the microscope images in ‘Gray’s Anatomy’ that fed my early Cell Paintings: chemical dyes have long been used to stain different parts of cells and tissue specimens bright colours for ease of identification (more on that in a future post).
By the time I got to my final year of art school, I was making a single painting using colour from some tens of different tubes of paint! My practice had begun to flounder in both my subject matter and painting technique, and my tutor decided now was the time to teach me something about colour. (With hindsight, I have looked over work I did nearly four years before, early in my Foundation studies, and realised I was taught the same thing then but it hadn’t stuck. It seems you do have to be ready or want to learn, it’s not just about the right teaching.)
Using a limited number of tubes of paint, it is possible to make all colours, and because such a limited number of initial colours are used to create them, aesthetically they work well together. They sit comfortably next to one another without jarring because they have a bit of one other in each of them. (How romantic!) The six basic colours are titanium white, yellow ocre, raw sienna, burnt sienna, burnt umber and ultramarine blue. From here, a single paint tube can be removed and replaced with a different tube, allowing different tones or shades of particular colours to be achieved, or perhaps made brighter and more intense.
This simple rule completely changed my painting style at the time; this new style is particularly evident in my collection of portraits. In these works I was searching for my own response to the microscope images of cells, focussing in as closely as I could to skin and hair, treading the fine line between portraiture and abstraction.
Towards the end of the portrait series, I found I no longer needed to produce colour charts in this way, and favoured the use of fewer tubes of paint: ‘Lilac Eyelashes’ (2005) was made using only light red, ultramarine blue and titanium white; ‘Blue Beard’ (2005) used only light red, prussian blue and titanium white.
Colour is important for some assays (tests, experiments) we do in biology too. Colorimetric assays use a chemical in solution together with a single colour reagent, and are typically employed to quantify how much of a particular chemical of interest is present (e.g. hormone or other small molecule). In some cases, the addition of an enzyme is required to produce the colour change. The relative colour intensity, monitored by the absorbance of light, is detected using a special microplate reader.
The most common assay of this type that I use in my research is either the Bicinchoninic acid (BCA) or Bradford assay for the assessment of protein concentration contained within a sample of interest (example given below). The left-hand two lanes are the standard solutions, 0.1-1 mg/ml bovine serum albumin (BSA, non-specific proteins from blood serum). The absorbance of these standards is used to draw a standard curve, from which the values of the ‘unknowns’ can be calculated.