Red and amberina

The breakthrough for the Carnival producers in making pressed red glass came in the 1920s with the use of selenium which produced a bright cherry red colour when the temperature control was exactly right. When selenium red is taken from the hot glass batch it is red. However, when it is then pressed in a mould, its colour becomes yellow. Re-heating causes the yellow colour to change back to red (a process known as “striking”).

The problem with selenium red was the difficulty in getting it to strike exactly right. When it didn’t, you can see some yellowish tones known as amberina. Note that most red was made by Fenton with some also from Imperial.

Red – true cherry red all over the item, also can be found with an opal edge (usually very light) - red opal

Amberina is the yellow-red shading that can often be found on red items, the yellow is in the centre of the piece, or on the base of the stem of a comport, for example, shading to red on the outer edge of the piece. Also amberina opal.

Reverse amberina is where the yellow shading is around the outer edges of the piece. Opal edges are also known (reverse amberina opal).

Brick red – a darker brownish red shade.

Red slag – with brownish streaks.