During this past year a series of two-hour introductory gilding classes have been held at Charles Douglas Gilding Studio in Seattle, an offer through Groupon which resulted in 240 students. In this issue we visit some of the recurring questions from these inquisitive students!

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Q. Oftentimes a canvas will be too large for a picture frame moulding which otherwise would be the perfect frame for a painting. Is there a way to deal with this problem?

A. If the selection of frame mouldings are pre-finished, then a frame profile with sufficient rabbit depth must be chosen. However, one of the major benefits of custom framing where a finish is being applied to raw wood frame stock is that a wood profile can be ‘built up’ by milling and adhering an additional wood section to the bottom of the raw wood frame to allow for proper fitting of the canvas.

One thing to note if water gilding such a frame is that the join seam between the frame and the build up will cause the gesso to crack when hydrated during the water gilding process. Therefore, as prevention, either a high quality Japanese paper like Sekishu or strips of very fine linen should be adhered over the seam with the use of rabbit skin glue. This is done before the gesso is applied and can help keep the gesso from cracking when it’s eventually gilded. This is a similar method used in the gilding of icons and panels where large flat areas can acquire crack mechanisms in the gesso layer if not first protected with an application of fabric to the surface before gessoing. These same thin strips of fabric, or Sekishu paper, may be used over frame corners to help protect against the typical cracking of the gesso at the mitres, creating a true closed corner frame.

Q. How do you know when it’s time to burnish a frame thats just been water gilded?

A. Burnishing, which is polishing the gold leaf with an agate stone, brings the leaf to a brilliant lustre while also compressing the leaf into the gessoed surface and therefore providing greater durability. Once the surface has been made wet and the gold applied, a certain amount of time must pass to allow it to dry and is contingent partly upon the weather and how warm the gilding room is. Generally 2-3 hours should pass.

I prefer to burnish when there is a small amount of moisture remaining in the gilding but burnishing at this stage needs to be done carefully. Tapping the agate burnisher against the gilding will produce a tone; a sharp click is a good indication that the leaf is ready to be burnished. A dull tone, however, means the surface is still too wet to burnish. If burnishing is done too soon it’s possible to break all the way through the gilding to the underlying wood. It would be best for a beginner to wait until the next day to burnish.

Q. What would be the reason to choose either oil size or acrylic emulsion when using a method of gilding other than traditional water gilding?

A. Oil size and acrylic emulsion, sold under such names as Water Based Gilding Size, Aquasize, or Wunda Size, are a form of mordant gilding. Mordant gilding employs the use of an adhesive to adhere gold, silver, or imitation leafs to a prepared surface. Other mordants include gum tragacanth, gum ammoniac, gum arabic, garlic, and glair (beaten egg white).

The use of oil size, which although is a form of mordant gilding, is commonly referred to as oil gilding. It’s a specially formulated varnish which produces a satin to semi-gloss tone in the leaf. It does not produce the high luster of traditional water gilding but it has an attractive appearance of its own. It offers a durable finish and is used for both interior and exterior gilding projects. It is also self-leveling whereby the oil tends to smooth out after it’s brushed on thinly. It cleans up with mineral spirits and so is somewhat messy to work with so be prepared to use rubber gloves, spirits, and perhaps some acetone in the cleaning of your brushes.

Oil size comes in different drying times ranging from 3 hour to 24 hour. In practice however, once a can has been opened the drying time becomes shorter and shorter. It’s best to open the can, stir the size to bring the driers to the surface, and pour some into another container for use on your project. This way you can close the can of oil size and preserve its life.

The water-based sizes are much cleaner to work with as they only need soap and water for cleanup; just make sure you clean your brush once you’re done as the size will harden and will require acetone remove the dried adhesive. One of the benefits of the acrylic emulsions is that once it’s applied to a surface it will come to the proper tack in about 15 minutes and remain properly open to gild for about 36 hours. The drawback is that it never seems to quite dry. A clearcoat after 24 hours can help protect the gilding from this effect.

Acrylic emulsions have a brighter appearance than oil size but do not have the brilliancy that you can only get from traditional water gilding nor does it share its almost magical tone and glow. As for which size to use, oil or water based, it’s important to know that most any high quality project which is not water gilded uses an oil size. That said, acrylic emulsions can provide a gilding option that is both quick and much easier for the beginner.

Q. Can oil gilding be given two layers of gold leaf?

A. Yes, oil gilding can be double gilded. The initial oil size should be allowed to dry 24 hours before re-sizing and re-gilding. However, this shouldn’t be necessary if the first gilded layer was done properly. If spots were missed or the size was painted on too thinly in spots, then a certain amount of spot gilding can be done, applying size only to those areas where leaf is missing, and then when it dries to a tack, apply small amounts of leaf to fill the holidays (breaks in the gold).

Conversely, traditional water gilding may be double-gilded for a more solid gild and stronger depth of gold tonal quality or to simply efficiently cover areas that may have been missed in the initial gilding.

Charles holds periodic gold leaf gilding classes in his Seattle studio located along the northern tip of Lake Union, offering short term studies in traditional water gilding, oil gilding, and glass gilding. A 20% discount is provided to all members of the EPFG.

‘Gilder’s Corner’ Courtesy of:

CHARLES DOUGLAS GILDING STUDIO Seattle, WA

206-795-8376    Website: www.gildingstudio.com  Blog:www.gildingstudio.blogspot.com