Is it safe to overpaint an alkyd/linseed paint with linseed paint? These Gamblin Faste-Matte paints have a calcium carbonate additive to help with adhesion, but I am worried about varying degrees of flexibility between paint layers, especially because I use a lot of linseed Titanium White in the overpainting. If not, is there a white you would recommend for underpainting?
Excellent question. Gamblin FastMatte Alkyd Oil Colors are named for their two distinctive qualities – they dry fast and with a matte surface quality. By “fast” we mean that they dry in approximately 24 hours when applied thinly. Their matte surface quality makes for a receptive surface to promote the adhesion of subsequent layers. The binder of the FastMatte colors is a combination of alkyd resin and refined linseed oil. Their main point of differentiation with other alkyd colors on the market is their use in underpainting. To further support this, each color is “leaner” than their traditional Artist’s Grade counterparts – for example, FastMatte Ultramarine Blue is leaner than our traditional Ultramarine Blue. So, to answer your question…yes, FastMatte Colors can be used in preliminary layers before linseed-oil colors are applied. FastMatte colors can be thinned with a small amount of solvent, though we recommend a 50/50 mixture of Gamsol and Galkyd, as this will effectively thin the color, yet retain its drying rate, matte surface and the appropriate amount of binder. Kind regards, Scott Gellatly, Gamblin Product Manager.
Thank you so much.
We will reach out to our industry contact at Gamblin regarding this question. In the meantime it sounds as if your proposed layering system is not going to cause too many issues so long as you follow the fat over lean rule. Linseed oil paints applied over alkyd-modified oil paints should be fine as long as there is sufficient tooth in the underlying layers. If you are worried about adhesion you might try adding a touch of solvent to your alkyd paints used for underpainting, adding less and less solvent (and even no solvent) to subsequent paint layers. Titanium White used in overpainting should be fine if you adhere to these rules. As for whites recommended for underpainting or indeed painting in general we do NOT recommend paints that contain Zinc white as this pigment is now known to create problems down the road. Check your paint tubes for the code PW4 (Zinc White) as often this pigment is mixed in with Titanium White. Lead white is also a fine pigment to use despite its reputation as a deadly pigment, a reputation that tends to get a bit blown out of proportion (see Number 1 on our “Myths, FAQs, and Common Misconceptions” document in the Resources section). As long you practice safe handling procedures and disposal methods (which you should be practicing anyhow) this pigment can be a joy to work with. But again be sure to check for Zinc white additions in any Lead white paint that you consider purchasing.
Great to know Scott. This clears up my one misgiving about the use of alkyd artists’ colors under traditional oil paints.