Candling is a method used in

embryology Embryology (from Greek ἔμβρυον, ''embryon'', "the unborn, embryo"; and -λογία, '' -logia'') is the branch of animal biology that studies the prenatal development of gametes (sex cells), fertilization, and development of embr ...

to study the growth and development of an

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

inside an egg. The method uses a bright light source behind the egg to show details through the shell, and is so called because the original sources of light used were

candle A candle is an ignitable wick embedded in wax, or another flammable solid substance such as tallow, that provides light, and in some cases, a fragrance. A candle can also provide heat or a method of keeping time. A person who makes candle ...

s. The technique of using light to examine eggs is used in the egg industry to assess the quality of edible eggs.

In Plants

This technique can also be used to assess the quality and development stage of certain translucent plant

seeds A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm ...

, especially those of Lilies and their close relatives. Ripe, viable seeds have a visible

within them when viewed in transmitted light, so good seeds can be sorted out from the non-viable seeds and chaff, if desired. Candling is a highly useful method with certain species that germinate erratically or very slowly, as seed germination causes the embryo to enlarge. Candling can thus be used to estimate the optimal time for planting seeds that are being

stratified Stratification may refer to: Mathematics * Stratification (mathematics), any consistent assignment of numbers to predicate symbols * Data stratification in statistics Earth sciences * Stable and unstable stratification * Stratification, or st ...

. Care must be taken during candling, as drying or overheating will kill the developing seeds.

In Lutherie

In lutherie, candling is sometimes used to check the thickness of the soundboard in various places, especially on lutes and historical guitars. This is especially necessary because these instruments have soundboards which vary in thickness, for instance the area where the

rose A rose is either a woody perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred species and tens of thousands of cultivars. They form a group of plants that can be ...

is carved. It is also used to check for any flaws in the wood, or to check how tight a joint is, for instance on the centre seam of the soundboard. Traditionally, a candle would be used, hence the name, but usually nowadays a modern light is used, as this is less of a fire risk.

References

External links

Pacific Bulb Society
- Information about candling lily seeds.
Candling and grading manual for shell eggs
- 1951 publication on egg candling by Kansas State Board of Agriculture. Poultry farming {{poultry-stub