How do you differentiate between a trade sample, a failed trial, and an experiment that did not justify full-scale production? Is it not the case that almost any rarity could be labelled a "failed trial", excepting, of course, specials such as de-luxe finishes, non-standard sizes, retailer exclusives, and other niche products?
I know of few items that can be categorised with some confidence. Perhaps the best example is the Pompeian bowl, Reynolds plate 21 (ii), which, despite the caption, carries the earlier trademark "WALSH". Only three such marked examples have been recorded, all of medium size and thus easily portable, unlike all other Pompeian not in the factory pattern books, and, thus, with every characteristic of being trade samples. How would you classify the Jobling Open-Footed vase, #11600, the original with the open foot? This is very rare, apparently because of production difficulties, and the mould was modified to close the foot but leave the sides open shortly after the original launch. I imagine that Jobling would have described both versions as production items, but there is a temptation to label the early version a failed trial today.
Are there not some dangers involved in introducing terminology and classification today that may not have been used then?
Always remember the problems that Heacock & Gamble caused everyone, including themselves, when they renamed Opaline Brocade "Spanish Lace" (or Spanich Lace (sic) in two captions in my copy of Book 9!). I have to smile over this as the pattern now always either makes me want to have a good scratch, or reminds me of a dark green vegetable artistically arranged over white fish! And we are not supposed to mention those dreadful, twee names they gave to Davidson and Greener Pearline patterns, so I won't.