One wood stain is pretty much
the same as any other, right? Well, not exactly. "Stain" is
a catch-all word used to describe anything that colors wood,
but the actual coloring agents in stains can be pigments,
dyes, or a combination of both. Dyes and pigments have only
one thing in common: they're both colored particles that
are used to add color to wood. Knowing how dyes and pigments
differ can open new possibilities when it comes to getting
the staining effects you really want.
Size Matters
If you think of a typical dye particle as the size of
a marble, the average pigment particle would be about the
size of a '59 Buick. The size of the particle matters a
great deal. While finely sanded wood may feel perfectly
smooth to the touch, if you look at it under a microscope
you'll see that the sanded surface has thousands of peaks
and valleys of various sizes. Obviously, the smaller dye
particles are able to get down into tiny spaces where the
pigment particles can't go, so dyes will give a "deeper" looking
stain effect than pigments.
Penetration or Colored Salt Vs Colored Sand
Think of dyes as colored salt. Dyes can be water-soluble,
alcohol soluble, or oil-soluble. When you mix dyes in their
appropriate solvent you get an evenly colored solution
that stays evenly colored indefinitely. Pigments, on the
other hand, are not soluble in any liquid. Think of pigments
the way you would colored sand. Mix pigments in any liquid
and eventually the particles will settle at the bottom
of the container. As the liquid portion of your stain penetrates
the wood surface it carries the dye with it into the wood,
leaving pigments to settle on the surface or in larger
wood pores. The solubility of dyes give them an edge when
it comes to wood penetration.
Advantages of Dyes
Dye stains typically lend a deep, even, "transparent" color
to wood because they penetrate so well. When you flood
it on and wipe off all the excess, the net result is color
that is in the wood rather than on the wood.
Advantages of Pigments
Pigmented stains typically lend a more "opaque" color to
wood because the large pigment particles remain on or near
the surface of the wood. The large size of the pigment particle
has distinct advantages. Some woods, such as oak and ash
have areas of very small-pore late wood and large pore early
wood. When you flood on the pigment stain and wipe off all
the excess, most of the pigment will remain in the large
pores, dramatically accentuating the figure in the wood.
Pigment/Dye Combinations
Most ready-made oil-based stains such as Minwax, Olympic
and Valspar, contain a combination of pigments and dyes -
the best of both worlds, so to speak. Flood it on, wipe it
off, and you'll have the depth of penetrating dyes in small
pore areas and the contrast of pigments in larger pores.
But don't forget to mix these stains as you use them: the
dye colors remain constant throughout the mix, but the pigments
will settle to the bottom!
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