Copper panels have been used as a support for oil painting since the Renaissance. Copper has the useful property of giving the applied paint a luminosity as well as allowing you to move paint around freely since it is completely smooth and non-absorbent. We were delighted to hear that Sophie Ploeg, an award-winning, UK-based art historian and artist, wanted to write for us about the experience of using a copper panel as a surface for an oil painting. She was the perfect choice since her superb and refined oil paintings, often inspired by 17th century culture, lend themselves so well to painting on copper. Her work enriches and exposes copper as an intriguing surface that creates an exquisite final piece.
How to Prepare a Copper Panel for Oil Painting
by Sophie Ploeg
Painting on or with copper has a long history. Copper based pigments have long been an important source of colour for artists, but copper plates have also functioned as a support for paintings, instead of the more familiar canvas or wood supports, for a long time. Copper was especially popular as a support in the 16th and 17th century and paintings from then are as vibrant and colourful as if they had been painted yesterday. It is a great support to work on. In this article, I will show you how to prepare a copper plate for oil painting.
Copper panels come in varying thicknesses. If you want to paint on copper, it does not really matter what thickness you go for but there are a couple things to keep in mind. If you work on a very thin sheet of copper, the plate will be bendable and flexible. And of course you don’t want your layer of paint to flex and bend so you will need to steady a thin plate. In order to do this you can adhere a rigid support (such as wood) on to the back with some archival glue.
If you are working on a thicker piece of copper, I am using a Roberson’s Copper Etching Plate which Jackson’s stock in various sizes with a thickness of 1.2mm, you will not need to support it. Do keep in mind that if you are working on a scale larger than A4 the plate will be very heavy. This is one of the reasons you will find the majority of copper paintings are small as anything big will just be too weighty.
Copper can show oxidation, if it is left exposed to air and humidity for a long time. If you have any unexposed areas in your painting (or leave the back uncovered by not framing it with a backing board) you will need to apply a varnish. That way the varnish will seal any exposed copper and protect it from oxidation. If you cover your plate in paint completely and cover the back with a backing board, you won’t have to worry about oxidation.
I would frame a copper plate with a backing board to avoid oxidation and any warping or bending.
You could leave your painting unvarnished if you wished, provided you hadn’t left any copper exposed, or you could varnish it as normal.
Smooth and Slick
Painting on copper is quite different from painting on canvas. There really is no texture whatsoever nor any absorbency on a copper support; so your paint will not be stopped in its flow by the weave of the canvas, nor the absorbency or the brush marks of your primer. Without anything to hold it back, the paint will flow and move easily: you can move it around the surface, pick it up and move it elsewhere. It is a little bit similar to painting on an oil primed support.
Because of the lack of absorbency and the reflective nature of copper, oil paint looks more vibrant, more transparent and more lively on this support.
However, not everyone will like working on copper!
How to Prepare a Copper Panel for Painting
Preparing a copper panel for painting on with oil could not be simpler. In fact, it is far less work than preparing most other supports.
This is what you need:
- a copper plate
- Methylated spirit for cleaning
- gloves [editor’s note: nitrile gloves protect your hands completely from solvents
- a lint-free cloth
The Methylated spirit is highly toxic so working with gloves is recommended as is good ventilation.
An unprepared copper plate is too smooth to paint on. If you do not prepare it a little, you run the risk that the paint will not adhere properly and could be peel off when dry. That’s something you definitely do not want!
So the first step is to take a fine sandpaper (the finer the sandpaper the less texture you will have; with coarser sandpaper, you will end up seeing sanding stripes and texture) and gently sand the copper surface.
Go around with regular movements to create an even surface. Not much dust will come off (do not blow) but you will see a texture appear on the copper. This is the oh-so-needed ‘tooth’ that will hold your paint in place. If your panel has sharp edges you can sand the sides a little too.
Using a glove to protect your hands from the cleaning agent you are using, pour some on a cloth and wipe over the whole surface of the plate. This will remove any dust, grease and dirt. Try not to touch the surface with your fingers after this stage.
You are now ready for painting.
Yes, it is really as easy as that.
If you are used to painting on a medium-grain canvas, do not be surprised how different this feels. Stick at it for a while as you will need time to get used to this support and figure out how it behaves. Once you get the hang of it, it is such a joy!
Try leaving some copper exposed (varnish afterwards to avoid oxidation!) or let it shine through some transparent paint. See how rich colours look richer when painted on copper. So how brush marks ‘sit’ on top of the support and do not get absorbed. Say goodbye to ‘sinking-in’!
Some people might prefer to work on a primed surface. You can apply an acrylic primer over the sanded and cleaned surface of your copper plate if you prefer.
Instead of oils you can paint with acrylic paint on copper as well.
The same preparation can be used for aluminium panels. For some aluminium products, I would recommend applying a primer after sanding/cleaning. I have found the paint bonding much stronger with the use of a primer than without on some aluminium panels.
If you’re inspired to start your own oil painting on copper or aluminium, Roberson Copper Etching Plates are available from Jackson’s as are a large selection of oil paints and aluminium panels. For more product reviews click here and to visit Sophie Ploeg’s website click here.