Gold leaf sometimes referred to as gold foil, is an amazing material that stays beautiful for many years. Does gold leaf tarnish? It depends. You can always tell genuine gold leaf apart from the impostors because it will still look as bright and colorful as the day it was applied. That is why gold leaf is used to decorate a broad variety of materials. But the amount of gold in your leaf matters. It could tarnish if there is not enough gold present.
Does Pure Gold Leaf Tarnish?
Even though you can find gold leaf ranging from 6 karats to 24 karats for sale, only the purest of leaves will not tarnish. The karat is the degree of purity. The lower the karat, the less gold is present. Something that is 18 kt or 20 kt will contain far more silver or bronze, or copper than gold, and that will alter the composition of your leaf.
If you do not want your project to tarnish, you will need at least 23.75 karat gold leaf. Gold is considered the noblest of metals because it is naturally resistant to corrosion. Pure gold leaf is resistant to snow, sleet, wind, rain, and rust. It will stay bright and beautiful for over 30 years with barely any maintenance. In fact, you do not even have to seal pure gold leaf.
21-22 karat gold leaf is commonly used in architectural gilding, because it is durable. However, even 22 kt gold leaf could darken with time.
Does Imitation Gold Leaf Tarnish?
Yes, imitation gold leaf will tarnish. Although it looks exactly like gold leaf, it does not contain any gold! Instead, imitation gold leaf is a mixture of brass, copper, and zinc. These materials are much less expensive than gold. Furthermore, none of these metals are resistant to corrosion, aging, and tarnishing. Brass and copper are known to gain a patina, for instance. This is why imitation gold leaf is not meant to be used outdoors.
Even when a protective top coat is applied to imitation gold leaf, it will turn dark or green after a few years.
How Can I Stop Gold Leaf From Getting Tarnished?
The purest gold leaf (24 karats) does not have to be protected from the elements, because it is resistant to tarnishing. Anything below 24 karats, including imitation gold leaf, will need to be sealed with a protective varnish. After applying the gold leaf to your project and letting it set, the next step is to apply a varnish or seal. You can do this by brushing or spraying the product onto the gold leaf.
There are many kinds of seals out there, but mineral spirit acrylic (MSA) varnish is an excellent choice for metals that tarnish. Apply three coats of the MSA spray.
If you plan on using acrylic paint or any medium painted with acrylic, know that the ammonia will affect any leaf containing copper. Seal the metal with a solvent-based varnish, in this case. However, if you are using acrylic with a leaf that will not tarnish (genuine 23-24 kt gold), you do not need any varnish sealer. Skip straight to the acrylic coat.
Using oil paint over the metal leaf? Choose a clear gloss acrylic medium followed by an MSA varnish.
Use genuine gold leaf for your artwork and design
Keep All That Glitters Gold
Does gold leaf tarnish? It depends. There are many kinds of metal leaf out there, but only a few, such as pure gold and silver leaf, will not tarnish. 18- and 20-karat gold leaf will darken if not sealed, as will anything containing copper or brass. As such, knowing the degree of purity of the leaf you are using is key to knowing whether your gilded project will tarnish over time.
Varnish will keep gold leaf from tarnishing. The purer the gold leaf, the less susceptible it is to darkening. Pure gold leaf will never tarnish.
Generally, gold leaf can last for many years. Outside, even unsealed genuine gold leaf will last between 20-30 years. Indoors, properly applied gold leaf will last 40-50 years. However, that only applies to gold leaf that is 23 karats or higher. Imitation gold leaf, for example, will only last 3-5 years.
Pure gold leaf will never tarnish or change color throughout the years. Imitation gold leaf, silver leaf, and 18 kt or 20 kt gold leaf will all darken over time due to oxidation. You must seal any gold leaf that is less than 23 kt to ensure that it does not fade.
Yes, imitation gold leaf tarnishes within a few years. That is due to the copper and zinc present in the leaf. You must seal your fake gold leaf in order to keep it looking like real gold.