Because these are antiques, they are subject both to flaws of manufacture
and post factory damage.
Manufacturing flaws, for example firing cracks, glaze pops, glaze
skips or runs--and bubble or straw lines in glass items--are generally non devaluing unless they are visually offensive. If
they are something that would not normally pass that factory's quality control, they are considered devaluing. For example,
a few glaze pops in a souvenir item by a low end factory are entirely to be expected. The same flaw in a Heubach
or Meissen is not to be expected.
A kiln-caused firing crack is usually a small irregular crack with
factory over-glazing and does not normally affect the competence of the item, nor is it usually devaluing. In contrast,
hairlines, chips, and fractures are devaluing and will be discounted for in the price. Sometimes the factory overglazed
a chip or "mold pull" in which case it is not a devaluing fault. Chipped applied work (for example on elfinware) is expected
and the amount of devaluation depends on extent and visibility. Old pottery is especially vulnerable, and as any
majolica collector will tell you, the presence of non-distracting chips is the norm rather than the exception.
I check each item carefully with a loupe and have made every effort
to include any described flaw in my site pictures and descriptions. If you question something, please ask me.
If you are unfamiliar with a term, Google is a great reference. For example, as a search term entry "firing crack" definition will yield many very good explanations.