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. Copper was especially popular in the 16th and 17th century and those paintings are as vibrant and colourful as if they were 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 comes 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. Of course you don’t want your layer of paint to flex and bend so you will need to steady the plate. In order to do this you can adhere a rigid support (such as wood) on the back with some archival glue.
If you are working on a thicker piece of copper (I am using Roberson’s etching plate which Jackson’s stock in various sizes ) you will not need to support it as it is 1.2mm thick. Do keep in mind that if working larger than A4 size the plate will get very heavy. This is one of the reasons you will find the majority of copper paintings to be small. Anything big will just be too weighty.
Copper can show oxidation if 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 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 don’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 can leave you painting unvarnished if you wish, providing you haven’t left any copper exposed. Or you can varnish as normal.
Smooth and Slick
Painting on copper is quite different from painting on canvas. There is really no texture whatsoever nor any absorbency. 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. 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.
Not everyone will like working on copper!
How to Prepare Copper for Painting
Preparing a panel for painting on could not be simpler. In fact it is much less work than preparing most other supports!
This is what you need:
The Methylated spirit is highly toxic so working with gloves is highly 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 peeled off when dry. That’s something we definitely do not want! So the first step is to take a fine sandpaper (the finer the less texture you will have, the coarser and you will end up seeing sanding stripes and texture) and gently sand the copper surface. Go around with regular moves 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, poor some on a cloth and wipe ovver the whole surface of the plate. This will remove any dust, grease and dirt. Try not to touch the surface with your fingers anymore after this stage.
You are now ready for painting.
Yes, it is really as easy as this.
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 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 Dibond (an aluminium product) 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 Dibond.
This post was written for and appeared originally on Jackson’s Blog