Polychroic wood conditioning.
Refractive foundation that maintain the woods wet mirror.

Aurea Lignum + Solum

Krentz String Works wood conditioning system consists of two complimentary products designed to be used together.

Aurea Lignum provides a complex, golden brown color to violin family woods without raising the grain. The texture and reflectivity intended by the maker’s tool work and surface finishing are retained and enhanced. Aurea Lignum is made with a combination of mineral salts, plant extracts and solvents commonly found in the Italian pharmacopeia of the 17th and 18th Century. As the product is free of water, it retains the cut qualities of the surface and avoids the need for any wetting then sanding or scraping of the instrument. The color it imparts to woods used to make violin family instruments is polychroic precisely in the spectrum found in Classical Italian instruments.

Solum is a refractive foundation that further enhances the effects of Aurea Lignum. It contains a complementary tincture with a trace amount of fossilized resin. It is provides a reflective and stable surface on which to begin the process of varnishing. It acts as an extremely light sealer that maintains the woods wet mirror beneath standard grounds and varnishes.

When living in Napoli in 2011 and doing research in the national library, we spent time investigating the inventory of the 18th century Farmacia Storica degli Incurabili, a breathtaking apothecary magically frozen in time. Italian Pharmacies in the 17th and 18th century were storehouses of medicines, dies, resins, mordants, stains, perfumes and plant extracts with extensive uses. It was common for painters, doctors, fabric designers , paper and varnish makers to pick up the ingredients used in their trade from their local chemist.

Aurea Lignum and Solum use components found in this and other pharmacies of the period and commonly used in wood crafts. Our research continued in France, with the assistance of a doctor of chemistry whose research focuses on plant extracts and salts used in wood treatments. Aurea Lignum and Solum were born out of this and extensive study of classical Italian instruments whose particularly complex wood color they emulate.

Farmacia Storica degli Incurabili. Naples, Italy.


These products work best if the white instrument has been in the lightbox first. This can be anywhere from three days to one month.

We recommend that spruce receive an initial coat of turpentine to create even penetration of Aurea Lignum. The product is then applied immediately afterwards in two successive coats. It is put on like alcohol varnish, with great awareness to even distribution, but without concern if there is slight overlap. Coat the entire instrument once, then again immediately, and put in the lightbox for 12-48 hours. If deeper results are desired, repeat the first step with after the primed instrument has been in the lightbox overnight. As each piece of wood is unique, we recommend using a sample piece of wood from each instrument to predetermine the results.

After the desired color is obtained, two successive coats of Solum will enhance the qualities of Aurea Lignum and create a refractive foundation on which to begin varnishing. For the application of Solum, no turpentine pre-coat is necessary for spruce.


Step 1

Light box for 3 to 30 days.

Step 2

Turpentine pre-coat on spruce.

Step 3

Two successive coats of Aurea Lignum.

Step 4

Check after 12-24 hours. If richer color is desired, turpentine pre-coat again and apply another two coats of Aurea Lignum.

Step 5

After two days to one week in the light box, apply Solum in two successive coats.

Step 6

Begin varnish process.

Wood Primer and Foundation by Krentz String Works

Order Yours Here Like Us on Facebook


1.What is this stuff?

A two part wood treatment for conditioning instruments that creates a complex golden brown and provides a refractive ground to start varnishing on.

2.What’s in it?

AE: A combination of four solvents, plant extracts, mineral salts and naturally occurring oxidizing agents.

Solum: A trace amount of resin and similar agents in AE.

3.Is it stain?

The products work through a process that is more akin to oxidation than to staining.

4.Does it have alcohol in it? Spike Lavender?

Yes, it has both of these along with two other (unnamed) solvents that allow for even dispersion and assimilation of the conditioning elements. All of these fully evaporate, and were widely used by 17th century painters.

5.Could these ingredients be found in the 17th or 18th century?

Yes, versions of all the ingredients are listed in catalogues of Italian Pharmacopeia of that period, extensive study of which led us to this combination.

6.Will it raise the grain? Do I need to wet sand?

One of the advantages of these products that they are not water based, so they will not raise the grain nor require pre-wetting of the instrument. Some slight textural changes may happen through brushing it on, so a fine brush is recommended. Lightly passing a piece of leather or simple burnishing after the conditioning process is complete can take care of any changes caused by brushing it on. But this is not necessary for most.

7.Does it have nitrites in it?

It has trace amounts of substances that act in a similar way, but with a longer molecular chain that are more stable and result in a golden brown hue, not the orange tint of nitrites.

8.Does is go very deep into the surface?

The treatment is actually very superficial, and checking this on a test piece is recommended. Two of the solvents used keep the products from penetrating deeply and disperse them on the instruments surface.

9.What if I want to thin them out or make them weaker? What do I use?

You can use ethanol on its own to do this for both products.

10.Is it lightfast?

Yes, all of the components are extremely lightfast, and in combination this is preserved.

11.How long is the shelf life?

Six months, more or less.


Have a question or would like to say hello?

Krentz String Works would love to hear from you. Of course we would like to answer any questions you may have. Further, if you have an idea to solve a problem that you have as a string player or a problem you would like to see solved, we would like to hear it!

Finally, Krentz String Works is obsessed with customer satisfaction and quality. If there is anything you need, don’t hesitate to contact us.

Krentz String Works
1215 NE 130th St
Seattle, WA 98125
United States

(425) 686-9365

Your Message Has Been Sent! Thank you for contacting us.
Oops, An error has ocurred! See the marked fields above to fix the errors.