I thought I had covered it all with my video on how to apply gold leaf. You know that old expression “everything but the kitchen sink”? Well that definitely applies to my gold leaf video (see it for free here) which gives all the tips and tricks for creating a gold leaf surface to paint on, and then how to prepare the leafed surface for overpainting with acrylic paint. HOWEVER, it appears I was amiss to include instructions on how to use oil paint on a leafed surface as well as how to leaf over oil paint! How silly of me. So here I go with additional information on using gold leaf with oil paint.
Real Gold Leaf vs Imitation Gold Leaf
First I want to repeat some info from that video to mention the difference between using real gold leaf and imitation (or composite) gold leaf (made with copper and zinc). In the video I explain why I choose to use the imitation gold leaf and not the real gold leaf for my painting purposes. In summary, these two types of metal leaf look exactly the same when using size (glue or adhesive) to adhere the leaf. Using real gold (involving extra expense) is worth the expense (in my opinion) when you will be showing it off uncovered and unpainted, like applying it to a picture frame, AND using a more complex application method. So instead of using adhesive you would apply the real gold leaf to your surface using a process called water gilding. In my paintings, I cover a good portion of the leaf by overpainting it with paint. So it doesn’t make sense for me to go to the expense of using a process involving water gilding with real gold, as most of the leaf will be covered when the painting is complete. I know there are some good reasons some of you may have for using real gold, and that’s fine. I just wanted to share my opinion.
On left is real gold leaf; On right is imitation gold leaf
Does Real Gold Leaf Need to be Sealed?
Real Gold Leaf does NOT tarnish. So you do NOT have to seal it, once applied to a surface, to protect it from tarnishing, regardless of whether you will be overpainting it or not. HOWEVER, the real gold leaf is so thin (like the imitation leaf only even more delicate) that once it is applied onto your painting, and not sealed, it can be easily damaged or marred if mishandled. So even though you do not need to seal real gold leaf, you may still want to seal it to add some protection from getting scratched or damaged. In other words sealing is optional but recommended over real gold leaf.
How to Apply Gold Leaf – over a primed or acrylic painted surface
Whether you are using real gold leaf or imitation gold leaf, the techniques for application using size adhesive are the same. So for this process, please watch my video (link here) to get all the information on how to apply real or imitation leaf with the process using sizing adhesive. That process of leaf application, is the same whether you plan to later overpaint the leaf with oil or acrylic paint. However, once you apply the leaf as per my video, then read below for changes in instructions, depending on whether you plan to overpaint the leaf with oil instead of acrylic paint. These changes are regarding sealing OVER the leaf prior to painting, and then a final seal over your completed painting (including both leaf and paint).
How to apply Gold Leaf OVER a surface already painted with Oil Paint
1. If you are applying gold leaf OVER oil paint, make sure the oil paint is fully dry before applying the adhesive and leaf. Drying times for oil paint depend on how thick the paint is applied, which paint colors are used, and your climate conditions.
2. Once your oil paint is dry, follow my video instructions (link previously mentioned) to apply the leaf using adhesive, BUT with one exception – use a solvent based size adhesive, NOT a water based size adhesive. In other words, don’t use water based products OVER oil paint. Instead use solvent based products over oil paint. Note: as mentioned above, if you are applying leaf to an unpainted surface (or already primed or painted with acrylic) you can use the water based size to apply the leaf, even if using oil paint later OVER the leaf.
Best way to tell if the size is solvent based or water based? The solvent based size will say on its container label to clean brushes with solvents, while the water based size will instruct you to clean brushes with water.
Are Sealing Requirements the Same for Oil Paint vs Acrylic Paint?
NO! There are two different sealing processes we need to consider. One is to seal over the leaf prior to painting. The other is to seal over your final painting including both leaf and paint. If you plan to overpaint the leaf with oil paint, you have a choice to skip the first sealing process that goes over the leaf, prior to overpainting. Instead you can opt to only seal once at the very end, over both leaf and oil paint when dry.
If, however, you are planning on overpainting the leaf with acrylic paint, then stop reading this article and just follow my free video (link here) because acrylic paint when applied, while wet, can tarnish unsealed imitation leaf, so you do not have the choice to only seal once at the painting’s completion. You must seal both prior to painting over the leaf, and also after your painting is complete.
SEALING OVER IMITATION LEAF PRIOR TO PAINTING WITH OIL
As mentioned above this is an optional step for oil painters. If you want to seal the leaf anyway, to keep the leaf from being accidentally damaged while painting and handling, watch my video and follow the sealing instructions with the following changes; make sure to use a permanent sealer or water based sealer (such as Golden’s GAC200 or GAC500), as opposed to any solvent based sealers (such as Golden’s MSA Varnish or Archival Varnish Gloss spray). You don’t want to use a removable solvent based varnish, because as you apply your oil paints the solvent in your paint mixtures may dissolve this varnish layer. One coat of a sealer is sufficient to protect the leaf while you overpaint with oils.
I repeat, DO NOT use Golden’s MSA Varnish (that I recommend for use as a sealer over the leaf when planning to overpaint with acrylic paint) if you plan to overpaint with oil. This varnish has UV protection in it, and one of the essential resins used in the varnish can interfere with the drying process of any oil paint applied over it. Instead, to seal the imitation gold leaf prior to applying oil paint, brush apply a mixture of Goldens’ GAC200 with GAC500 in an approximately 1:1 ratio.
SEALING OVER FINAL PAINTING – including both leaf and paint.
As a final varnish, over the leaf overpainted with oil paint, you can use Goldens Archival Varnish Gloss spray, Golden’s MSA Varnish or other archival removable solvent based varnishes as a final finishing coat. Here it is OK to use the MSA Varnish OVER the oil paint, but as I cautioned above, do not use it UNDER oil paint.
Important note: When using imitation gold leaf you must seal at some point within 6 months after application, so it will not tarnish from exposure to air.
Important Reminders for Acrylic Painters
Imitation leaf will tarnish TWO ways. It will tarnish when exposed to air, and also when exposed to the ammonia in acrylic products while the acrylic is still wet. Once the acrylic dries the ammonia has dissipated and will not tarnish your leaf. SO, if you are applying acrylic paint over REAL gold leaf you can opt to wait to seal at the very end when your painting is complete. If you are using imitation gold leaf along with acrylic paint, you MUST seal the leaf BEFORE you apply any acrylic paint or acrylic products over the leaf.
Seal imitation leaf using a water based acrylic sealer or water based acrylic varnish IF AND ONLY IF that product is applied very thinly or is super fast drying – so fast the ammonia will dissipate before it can tarnish the leaf. Do NOT use Golden’s Polymer Varnish over unsealed imitation leaf. It does not dry fast enough and will tarnish imitation leaf. As I mentioned before, Golden’s Archival Varnish Gloss spray or Golden’s MSA Varnish are solvent based and therefore perfect for sealing leaf because they will not tarnish the imitation leaf. These are both toxic and you will need protective gear and safety precautions. If you want to use a non-toxic alternative such as brush applying Golden’s GAC200 or GAC500 (I use a 1:1 mixture combining both) be very careful to apply your first coat thinly so it dries fast. Also, you must apply several coats, letting each dry prior to applying the next, if these are your only sealers over the leaf before painting with acrylic.
Apply oil paint directly over real or imitation leaf without any need to seal the leaf before painting. Apply acrylic paint directly over real gold leaf without any need to seal the leaf prior to painting. Sealing any leaf, real or imitation, prior to painting will protect the leaf from damage while handling.
Do not apply water based adhesives OVER oil paint to adhere your leaf. Instead use solvent based adhesives.Do not apply oil paint OVER removable solvent based varnishes and sealers. But these same sealers can be applied over the oil paint and leaf at the very end as a final coat.
When applying acrylic paint over imitation leaf, the leaf MUST be sealed before painting to avoid tarnishing.
It’s a good idea to varnish paintings at the very end when your painting is complete, even if you already sealed the leaf prior to painting. Sealing with an archival varnish over leaf and paint, is a recommended archival process that enables the painting to be cleaned, and adds UV protection.
Nancy Reyner, painter, author and instructor offers assistance to artists in a variety of ways. Click here for more info.