Despite all this, please consider the logistics of a massive semi- and fully-automatic plant. A tank furnace would feed the presses, and the only ones I have seen are the size of a house. A large house. So the molten metal is fed to the presses in a continuous process, churning out all manner of things, in quantities of up to hundreds of thousands. Britannia was one of the most popular patterns and although I don't have the entire production records for the 3½-in pin dish (1D155) I know it was producing 2,400 per hour. This was one of the most productive items Chance produced (the largest quantity I have found recorded was a 3½-in Prismatic Liner where 750,000 were made at 2,760 per hour). The dishes were double pressed on a PBB machine with 1D174
(which was a 3½-in Liner
) - I imagine this meant they simply used two different, but similarly-sized moulds, to produce two items at the same time.
Much of the domestic-ware was produced in quantities over 100,000 and from this smaller quantities were then called off and sold on as required, or decorated accordingly: sprayed exterior; gold rims; crinkle bands; drilled centre holes; etc.
But when did they find the time and money to interrupt this process and change the tank furnace to opal glass? Obviously they didn't, as it takes several days for the new colour to work through the system, which would mean lost production and paying men to sit around doing nothing (or laying them off). They did change colours with rolled-plate glass, which may be why, incidentally, that certain textured glass has a paler tint - possibly used for Fiestaware, rather than scrap it, but that's another story. It is also worth noting that the Pressed Division was in difficulties from c.1950 and, according to reports, was not terribly profitable. So the works management were probably desperate to achieve high production figures, although its pressed Domestic ware was halted in late-1953.
To explain the very few items that are not clear glass (I only know of three, all Spiderweb), this would have meant wheeling in a small mobile pot furnace loaded with opal glass, feeding gobs into the mould and hand-pressing the item. OK, perhaps they did this as an experiment, but I very much doubt they were foreigners. But any dishes having the Royal commemorative transfer affixed, surely would have been stock production items, hence I can only conclude this is a spray enameled exterior. And why hand-press a few Britannia pin dishes, when there were thousands in stock?
It is quite reasonable and easy to assume a non-transparent glass is self-coloured. However, I have seen "opal glass" offered on ePray
, when it looks distinctly like... porcelain! In fact, I recently bought a Victorian beaker, which was exactly this
Never mind, it was cheap.
I am no expert in these matters, this is what I have gleaned, learnt and pieced together. Adam Dodds may be able to firm up on these points, or even disprove them. I'll also give Ray Drury a call later for his opinion.