Oil paintings always need varnishing. Firstly they need protection.
Once varnished the painting has a strong layer over the paint, so it is easier to handle as it can then be cleaned. If the painting is left unvarnished it could easily get damaged. As the painting dries out the oil paint tends to get duller and gives a matt finish. However, you cannot varnish until the paint is completely dry and this can take a considerable amount of time.
I think sometimes you would probably need to clean it first. Ordinary liquid detergent should be quite sufficient to do this. Using only a very small amount diluted with cold water to cover the surface of the picture, rubbing it very gently with a soft soaked piece of rag. Then maybe do the same with clean water, so there is no residue of the detergent used. It then needs to be left to dry thoroughly in a warm atmosphere.
Personally I would say it is better to do your varnishing somewhere that has a good dry atmosphere with warmth. If the atmosphere is moist, the varnish often may appear to go into patches of white, which I personally find infuriating.
Now it is possible to obtain good spray varnishes which dry fairly quickly. Most artists probably prefer to apply varnish with a brush. Probably a fairly wide, soft brush is best. Generally better if the varnish, brush and painting have been near heat so there is no damp. Lay the painting on a flat surface. I pour some varnish into an old tin lid and then very carefully and gently brush on.
It is tempting to go backwards and forwards and overbrush – not so good – as the varnish tends to create bubbles. Easier if you have a small painting, because you can go straight across from one side to the other. You have to endeavour to get as even and as thin a coat as you can. Tendency is to over-varnish, giving a thick layer and an annoying glossy finish.
If your painting is large it is somewhat easier to divide it into square sections and work laboriously on one section at a time. Once you have applied the varnish do try not to disturb it.
Then you need to find a place to put the picture where, while you are working on it, you can see where the light shows on the varnish. This way it will enable you to see any places that you may have inadvertently missed.
Your picture then needs to be in a preferably dust free area if possible, with the face side up.
Then you may find that you need to retouch your varnish. Obviously for this you need a thinned down varnish, especially where you may have what appears to be dull parts. Just be careful not to use too much, but it is quite alright to use it on top of half dry paint.
It is fairly usual to think the painting looks dull as it is drying – this is often the result of overpainting layers.
Source by Anna Meenaghan
Disclaimer: The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of Irish Artmart.
