Basic gold leaf is sold in books of 25 leaves, often from art supply stores. Different purities are available, but the commonest values are 22 karat and 24 karat. Sheets are generally 3 3/8 inches square, held between pages of tissue paper.
Other metals, such as silver and aluminum, are also available in leaf form. They also come in books of 25 sheets, usually 3 1/2 to 5 1/2 inches square, and may be thicker than the gold leaf. The handling characteristics will be the same as for gold, though thicker metals may require a stronger adhesive.
Note that, because it is ingested in such small quantities, gold leaf can be used as a decoration on food.
Alternatives
Working with leaf takes practice, and practice can be expensive. To get a good result for less money, you can use something that looks like gold but isn't, use gold that has been treated to make it easier to handle, or a combination of the two.
Alternatives that still look like gold
Treatments to simplify handling
- gold foil
- Adhesive-bonded leaf
This is gold leaf (or other metal) which is stuck to a sheet of plastic by a very weak adhesive. If you're gilding directly onto size (or another tacky adhesive), then the weaker adhesive bonding the metal to the plastic will yield when the leaf is pressed down on the stronger stuff. It cannot be used with heat-activated adhesives such as glaire.
Handling
Gold leaf is incredibly finicky stuff to deal with, because it's so thin. Its behavior is affected by things that are otherwise so innocuous that we don't even think about them in a normal environment. However, the same factors that can make any leafing process almost impossible for the beginner are tools in the hands of a master (or so I hear). I have listed them in ascending order of influence.
This is also the order in which you should handle gold leaf. Always plan to transfer it from a weaker hold to a stronger hold.
- Gravity
- Air
Even the slightest draft can blow unattached gold leaf off of your working surface. The first time I opened a book of gold leaf and looked at a piece, I sighed. The leaf immediately wrinkled up and folded over onto itself. Now I hold my breath when I work with it, turning my head to the side to gasp from time to time.
They say great artisans can control gold leaf with their breath alone, gently blowing it into place. I suspect this is an achievement on a par with catching a fly with chopsticks.
- Static electricity
Like anything thin enough, unattached gold leaf will stick to a statically charged surface. This is the principle behind the gilder's tip. Because static is the weakest tool to pick up gold leaf, it will relinquish its hold easily when the gold meets a stronger attractant.
- Tensile strength
Gold leaf, despite being thin, has a certain strength. It takes a slight but noticeable force to cut it or make it tear. This tensile strength is greater than the power of static electricity, but less than the attractive strength of oil. This means you can pull a piece of leaf off of a gilder's tip by a corner, but if it's stuck to oil it will tear.
- Oil
Gold sticks to oil. This is why you never, ever touch gold leaf with your fingers. The same sebacious oil that makes fingerprints will also stick the leaf to your fingertips. It's also the reason for using an oil-free surface such as a gold pad if you're not transferring the gold leaf directly from the book to its final position.
If you're using a heat-activated adhesive like glaire, then Vaseline or olive oil is used to hold the gold leaf in position until tooling makes it permanent.
Lesser amounts of oil will yield to greater amounts, to a certain extent. If you don't have a gilder's tip, you can wipe a cotton bud or cotton batting across your face to pick up a tiny bit of oil. Gold leaf held this way will still yield to a more heavily oiled surface.
- Adhesive
The whole point of this fiddling about is to get the gold leaf to a permanent location, and adhesive is what makes it permanent. Different uses of gold leaf (such as gilding and gold tooling) will require different adhesives.