The two aspects of color and surface finish are important factors in any bead design. However, the same color bead can appear totally different depending on its type of glass and surface finish (or lack thereof).
Colors that come Forward and Recede in a Design
Opaque colors and shiny surface finishes (metallic, luster, and iridescent) come froward in a design Transparent and greasy glass as well as matt surfaces tend to recede optically. Therefore, transparent and greasy colors, and matte surfaces are best for shadows and backgrounds. Opaque glass and luster, metallic and iridescent surface finishes are best for highlights and design accents. If you are unsure, make first a small sample incorporating the colors you wish to use and study their effect.
Glossary of Glass Type
TRANSPARENT = glass that transmits light, so you can see through the beads. Although transparent beads are more glittery and lively than opaque beads, they tend to recede optically in a design.
OPAQUE = glass that transmits no light. You can't see the yarn inside opaque beads. Opaque colors come forward optically.
GREASY = glass is somewhere betqeen transparent and opaque: the glass transmits light yet you cannot see through it. Greasy beads have depth and richness. Greasy colors recede optically in comparison to opaque colors but come forward when used with transparents.
WHITEHEARTS = glass that have an inner core of white glass. Among the most sought-after beads today because of the subdued intensity of their color. Originally, these beads were quite cheap, since one saved colored glass which was costlier than white glass. Rare original colors include gold-based lavenders and purples. Common colors are rose, red and turquoise. Optically they behave like greasy beads.
GOLD-LINED = beads are transparent colorless beads lined with genuine gold. They are stunning. Occasionally we find old ones. The Japanese are producing some beads they call "gilt-lined", but the "gold" lining looks more like silver. Gold-lined beads stand out elegantly in a design,.
COLOR-LINED = the holes of a transparent beads is coated with a separate, opaque color. Because the color is inside the hole, these beads are more durable than surface painted beads. However, avoiud exposing pinks, reds and purples to direct sunlight since they may fade. Color-lined beads stand out subtly in a design.
IRIDESCENT (also called iris, oil slick, AB "Aurora Borealis", scarab, rainbow) = each of these terms refers to the same thing: the permanent "rainbow" finish which is applied while the bead is hot. An iridescent finish can totally change the original color of the bead. Iridescent beads blend subtly into a design. The rainbow finish saccentuates the beads, making it come forward optically.
LUSTER = a uniform, shiny finish on the surface of a transparent, translucent or opaque bead. Luster may be white, colored or even gold. "
MATTE = beads that have "frosted" , matte (not shiny) surface, rather than a brilliant or reflective surface. Some really old beads seem to have a matte surface due to their rubbing against each other over decades. All matte beads recede optically next to any shiny bead. Matte colors are saturated like greasy glass. You can matte beads yourself using glass etching compounds (use caution - they are caustic!). Also, etching luster iridescent or metallic beads will remove their surface finishes.
MATTE IRIDESCENT = beads that are iridescent and matte. For a real contrast use a matte iridescent bead with a shiny iridescent bead. Matte iridescent beads look similar to Raku pottery.
Abbreviation: MAT IRID
MATTE METALLIC = beads that are metallic with a matted or satin gloss finish. They may not be permanent. Use a matte metallic bead with a shiny metallic in the same color for a subtle background texture.
Abbreviation: MAT MET
METALLIC= beads that are normal glass beads with a shiny metal-like surface coating. The finish may be applied as a baked-on paint or electroplated onto nickel-plated (glavanized) beads. Electroplated beads are permanent although over time the thin gold coating may wear away. Non-iridescent metallic finishes are open to question. Test the beads with chlorine bleach or alcohol. To protect these beads somerwhat, spray them with 3 or 4 coats of an artist`s fixative. Red, pink and purple metallic colors may fade if exposed to sunlight for any length of time.
Metallic beads are only rivalled by metallic iridescent beads in their visual prominence in a design. All other glass types and surface finishes will recede in comparison to metallic beads, because they are both opaque and very shiny.
METALLIC IRIDESCENT = beads are iridescent and metallic. The bead may be a metallic color such as gold, bronze or silver with an iridescent finish. The bead may also be an opaque color such as blue, green, purple or black, coated with such a heavy iridescent finish that it looks metallic. These metallic finishes are permanent, as opposed to the plain metallic, which may not be. These beads integrate well into a design and come forward visually compared to beads without any surface finish.
Abbreviation: MET IRID or MET AB
PAINTED or DYED = colors like bright purple and fuchsia that are achieved with surface colorants which are applied after the bead is made, generally with heat and solvents.
Transparent beads are labelled "dyed"; opaque beads are labelled "painted". They can fade in sunlight, the same as metallic beads, with red/violet/pink beads being the most susceptible ones. Modern dyed/painted beads are very durable, more so than many metallic beads. The painted/dyed beads behave just like normal opaque, greasy and transparent beads but the colors tend to be brighter and therefore stand out more.
Seed Bead Sizes
After measuring countless beads, it seems that many seed bead suppliers use a slightly diferent scale for measuring seed beads. A 10/0 from one source ends up being an 11/0 from another source etc. Seed beads are measured across the belly. sometimes a size lies just between two sizes and can be allocated to either one. One is for sure: the sizing of seed beads is not an exact science. The following list is not the "measure of all things" but will provide you with a good guideline:
Size 10/0 = 2,40 to 2,55 mm
Size 11/0 = 2,10 to 2,25 mm
Size 12/0 = 1,85 to 1,95 mm
Size 13/0 = 1,73 to 1,78 mm
Size 14/0 = 1,58 to 1,68 mm
Size 15/0 = 1,30 to 1,40 mm
Size 20/0 = 1,02 to 1,08 mm