What? Why? & Will it work?

In this journal entry I want to give a better idea of the  materials I currently work with, why I’m interested in finding alternative ways to colour anodised aluminium, and some of the questions on my mind as I make a start.

What is anodised aluminium anyway?

Anodising is an electro-chemical process. Unlike paints or plating, anodising isn’t a surface colouring, anodising converts the surface of aluminium into an oxide which is hard and ceramic-like, and fully bonded to the aluminium within. This oxide can remain as a grey aluminium or can be coloured.

As a comparison, when working with titanium or niobium a variety of colours are created at the point of anodising, through a change in voltage. However, anodising is just the preparation for aluminium colouring, after which it can then be treated using a variety of decorative techniques.

To give a brief overview, the Type 2 anodising process goes like this…
Following a series of cleaning and degreasing steps, the aluminium piece is placed into an electrolyte to form the anode in an electrical circuit. The electrical current causes oxygen to be released at the anode which combines with the aluminium to form an aluminium oxide. This is known as the anodic film.  The depth of the anodic film is determined by the time in the anodising tank, usually between 30 to 60 minutes.

This oxide is a honeycomb-like structure of microscopic pores which extend from the surface down through the oxide coating. Once anodised, dyes can fill these pores. When absorbed, a sealing process closes the pores permanently, trapping the dye within the oxide and forming a hard ceramic-like surface which is fully bonded to the aluminium within. The colourants I currently use are designed specifically for anodised aluminium. 

Why bother making colour from nature?

My reasons for exploring natural dyes are multi-faceted. 

Using colour as a record of a geographical location is an idea which has been percolating in my mind for some time. I am keen to extend this idea from colour replication to producing colourants themselves from, and of, a place through the plant material found there.  I am hoping to create a healthier studio practice by finding alternative colourants to the synthetically produced dyes and solvent screen printing inks I currently use in my work. Ideally, creating dyes which can come from the land and return to it with minimal impact. Finally, by producing colourants myself I hope to have more control over supply, albeit at a slower pace.

Will it work?

I am navigating unknown waters.  Will the dyes take at all?  If they do, will they be stable and lightfast? Do I mind if the colour changes over time? Is it time for us to favour material honesty and natural living-colours rather than static perfection?

What’s next?

Under the expert guidance of dye historian and researcher Deb Bamford, I’ll be spending some focused study time at a dyehouse in Bradford, getting to grips with the basics of natural dye making.