Base enamels for painting
by Mer Almagro, April 2021
The enamel used as a base for painting on enamel interacts both physically and also chemically with the vitrifiable pigment that will be applied on top.
The physical aspect refers to its colour & opacity, and how this interacts with the colour & opacity of the vitrifiable paint. The traditional base for painting is an opaque or opalescent white, as a neutral base that will not influence the colour of the paints and will show them to their best advantage even if they are not the most opaque. However a multitude of effects can be achieved by changing any of these variables, in accordance to the artist’s objective.
Besides this, the chemical composition of the base enamel also affects & interacts with the paint, and this should be taken into consideration when choosing the base. Some aspect of the texture & opacity of the fired surface also seems to affect the behaviour of the paint, some enamel bases acting as an easier surface in which to work, particularly when it comes to fine, minute gradations.
There isn’t a single base that can be recommended for all types of work, but after extensive testing I’ve come to the conclusion that Schauer 64 opalescent white (applied directly on copper) is as close as it gets. It works very well with all our colours (and every other vitrifiable paint I have tested) and makes the work easy. This is thus my go-to recommendation for a versatile base. As mentioned, I have done a lot of tests in order to offer the best enamels for a particular purpose in my store. You can see just some of these tests at the end of this article. From these I have made a selection due to their properties and availability, reducing the number of enamels I recommend as a white base to the 4 that I mention in this article.
If you find this article useful, I do ask that you consider supporting this store and further testing, selection & recommendations on my part by purchasing your materials through us. For that you have my gratitude.
There are however other options that can be considered, in particular when particular effects are sought after.
The best way to find the perfect base for your particular project is to do the testing yourself, as only you know what it is that you need. However I do hope the following can serve as a general guideline. A particularly useful testing tool, I find, is a palette with multiple bases fired together, over all of which the paint is applied and thus fired at the same time under the same exact conditions.
From these tests it appears that most colours, due to the metallic oxides utilised to colour them, are not chemically affected in great measure by the base enamel, with the notable exception of:
- Cadmium-bearing colours (yellow*, orange, red*)
- Gold-bearing colours (pinks and carmine-purples)
- Black (usually combinations of several oxides such as cobalt, iron and manganese)
In particular, the needs of gold+black are opposite those of cadmium, behaving best on the bases that perform worse for the other. Again, as a neutral base good for all colours, I can recommend Schauer 64 and also Blythe T6 opaque white.
Gold-bearing pinks develop faster to a rosy hue on a softer base such as Schauer 202 opaque white, while on this same base cadmium based pigments show a strong tendency to burn out much faster, and black pigment shows a tendency to turn green, particularly after repeated strong fires.
Cadmium-bearing yellows, oranges and reds are best preserved on a hard base, Milton Bridge ODW1 showing a remarkable synergy with these pigments, to the extent that even slight gradations, not possible on other bases without some degree of blackening, are possible on this base (I do not recommend to apply this enamel in combination with others as a base, due to different coefficients of expansion: it is best used alone as a base for painting, including the counter-enamel). Blythe T6 exhibits similar properties although to a slightly lesser degree and it is an excellent base for painting. Black shows the least degree of turning green when applied over these bases as well. Conversely, on these hard white bases, gold-bearing pinks have more difficulty developing intense rose hues, though this can to some extent be countered by applying these colours first and firing more intensely to develop them.
As mentioned above, the surface or opacity of the base itself affects the progress of the work on very fine gradation, and this is very clearly apparent when performing these tests, Schauer 64 being the one in which soft gradations are easiest to perform (and generally speaking all opals have this softening property), followed by T6, 202 and finally ODW1 making the work harder. This is clearly apparent in the tests, click on the pictures to be able to zoom in to the details.
*Not all yellows or reds. We always indicate when a colour contains cadmium.