Saturday, April 3, 2010

Lead, Titanium or Zinc White; Which is Best?

Continuing the discussion of white paint available to the oil painter, I will go a little more deeply into the characteristics of individual white pigments. When determining the 'best' white to use, there is no single way to decide this. A white is chosen based on the needs of the artist in that moment. Lead white, titanium white and zinc white vary greatly in their properties: opacity, toxicity, drying time, etc. With such differing properties, I believe it is so essential to determine the actual pigments contained in the white being used regardless of the name of the paint.

Toxicity varies to extremes. If a strict non-toxic palette is desired, titanium white is the choice.

Titanium white is considered to be non-toxic unless inhaled. Caution with dry pigment or sanding.  2
Zinc white may have traces of lead. Moderately toxic by ingestion. Less toxic by inhalation.  1
Lead white is toxic and should not be ingested, or inhaled (when sanding, scraping or spraying). I believe it wise to keep lead white off of one’s skin: wear gloves and other barriers when painting. Keep out of reach of children.

Drying Time:
Drying times vary greatly. A fast drier will hasten the drying time of any paint it is mixed with. A slow drier will lengthen the drying time of any paint it is mixed with.

Lead White: Fast (a few days) 2, 3
Titanium White: slower 2
Zinc White: slowest 2

Because the most opaque oil color of all is white, 3 it has excellent covering capacity and tinting strength. The opacity varies among the whites, however.

Lead White: Opaque
Titanium White: Opaque
Zinc White: Semi-transparent

Permanence and Lightfastness
All three whites have excellent permanence and excellent lightfastness.
However, the tendency to yellow over time varies.

Titanium White: Tendency to yellow less than zincs…but still yellows easily. 2
Lead White: “May become discolored over long periods of time.” 1 May “blacken when exposed to sulphur in the air.” 1
Zinc White: Tends to yellow. 2

White Paint Ingredients- What's in the Tube?
Earlier I stated, I believe it is so essential to determine the actual pigments contained in the white being used regardless of the name of the paint. Below is an example to illustrate this point.

Let us suppose I want a fast drying white paint with high covering capacity. I may choose lead white. Many know that the terms 'lead white' and 'flake white' are used interchangeably. A tube of white paint with the label, "Flake White" would lead me to believe that the only pigment in the tube was lead carbonate. I would be wrong to believe something so (seemingly) obvious!

Blockx "Flake White" and Williamsburg "Flake White" do contain only the pigment lead carbonate. However, Sennelier "Flake White" contains both lead carbonate and zinc oxide. The Sennelier "Flake White" has the same pigments as  Blockx "Mixed White," Old Holland "Flake White 1," and Michael Harding "Flake White no. 2."

If I want pure lead carbonate in the Old Holland or the Michael Harding lines, I need to buy the "Cremnitz White." 4 If I want it in the Sennelier line, I'm out of luck.  And Gamblin "Flake White Replacement?" No lead carbonate at all, just titanium and zinc. In a later post I will list white paints by brand and content.

In the next post about white pigments, however,  I will address specific uses of the white paints.
1. Blick, Dick 4/03/10
2. Blick, Dick 3/03/10
3. Creevy, Bill The Oil Painting Book, Materials and techniques for today’s artist, 1994, Watson-Guptill, New York
4. Harding, Michael 3/15/10

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