ON SHIFT KEYS AND CALCULATORS

Ever since HP came up with the HP-80, HP calculators have usually sported shift keys of different colors. Going through my collection of pictures for true calculators only (i.e., eliminating things like the HP-75, -01, -9805, etc.), I have concluded that HP must have a predilection for the gold shift keys -- and the blue shift keys in second place.

Here’s my compilation.

Black: 3 counted (27, 34C, 67).

Blue: 22 counted (11C, 12C, 15C, 16C, 19C, 20S, 21, 21S, 22S, 25, 27S, 29C, 32E, 33C, 34C, 38C, 48SX, 55, 65, 67, 92, 95C.

Dark blue: 1 counted (49G).

Dark red: 1 counted (28C).

Gold: 36 counted (10, 10C, 11C, 12C, 14B, 15C, 16C, 17B, 18C, 19C, 20S, 21S, 22, 25, 27, 29C, 31E, 32E, 32S, 33C, 34C, 37E, 38C, 41C, 42S, 45, 48SX, 55, 65 (two of them!), 67, 80, 91, 92, 95C, 97.

Green: 1 counted (81).

Purple: 1 counted (48GX).

Red: 2 counted (46, 49G).

Teal: 1 counted (48GX).

In preparing the above list, I have not included “variations” of each machine. For instance, I have counted the HP-25 but not the 25C. Similarly, there’s mention to the 41C but not to the 41CV or 41CX.

Also, sometimes the hue varies. For example, although the 32S is included among those having a gold shift key, the key is practically orange.

Trivia:

* The HP-27 is the only calculator in which the [g] shift key is black.

* The HP-65 is the only calculator having two gold shift keys.

* Only two calculators have had 3 shift keys: HP-34C and HP-67.

* Only two calculators had no shift keys: HP-35 and HP-70. Coincidence that 35 * 2 = 70?

* The HP-70 is the only calculator ever to have (ugh) orange keys.

Question: What made HP decide on gold and blue? My feeling (purely conjecture) is that most color-blind people can tell them apart; if they were red and green, they’d look the same to them.