THE MISTERY OF
THE GRAY-BLUE DIALS

There are at least four types of blue or gray-blue dials that were probably produced in the 1960s, or the early 1970s. We have seen very few examples and we have yet to come across a clear explanation of their origins and status.
TYPE 1. GRAY
DIAL
COLOR
Gray
DIAL
FINISH
Sunburst matte
MARKERS
TYPE
Long
MINUTES
SCALE
Normal
PRE-PRO. /
PRO.
Both
Ts
POSITION
Close / distant
This first dial seems to have all the characteristics of the standard production of the pre-Professional and Professional models of the 1960s.
However, it has a sunburst matte finish and is colored gray with a bluish tinge. It is moreover the least blue of the four types. Its sunburst finish indicates that it is unlikely to be a faded version of the original black.
These dials have been recorded on ST 105.003 and ST 145.012 models (illustrated here).
TYPE 2. GRAY-BLUE “WIDE MINUTES SCALE”
DIAL
COLOR
Gray-blue
DIAL
FINISH
Uniform matte
MARKERS
TYPE
Long
MINUTES
SCALE
Wide
PRE-PRO. /
PRO.
Both
Ts
POSITION
No Ts
The second category is distinguished by a blue-gray color with a uniform matte finish. Its main feature is the minutes scale of a larger diameter than those of the conventional dials and is thus located farther towards the edge of the dial. This gives rise to two significant differences:
– the main indexes and the two luminous dots at 12 o’clock hardly touch the edge of the central zone;
– the SWISS MADE inscription is extended to the very edge of the dial so that it becomes invisible at certain angles.
This category can be seen on the pre-Professional dials of the CK 2998 (illustrated) and the ST 105.003 models as well as on the Professional dials of references ST 105.012 and ST 145.012. All of them lack the Ts flanking the SWISS MADE inscription.
TYPE 3. METALLIC BLUE “LONG MARKERS”
DIAL
COLOR
Metallic blue
DIAL
FINISH
Sunburst glossy
MARKERS
TYPE
Long
MINUTES
SCALE
Normal
PRE-PRO. /
PRO.
Pre-Pro
Ts
POSITION
Close
TYPE 4. METALLIC BLUE “SHORT MARKERS”
DIAL
COLOR
Metallic blue
DIAL
FINISH
Sunburst glossy
MARKERS
TYPE
Short
MINUTES
SCALE
Normal
PRE-PRO. /
PRO.
Both
Ts
POSITION
Distant
THE CARAMEL PATINA
We know that some black dials of the 1960s/1970s may have turned into a chocolate color due to an oxidation process (we wrote a specific review of these tropical dials here).
Basically, most of the dials have an additional layer of protective varnish to prevent oxidation of the plating and the deterioration of their color. However, the varnish was sometimes porous and of varying quality. Humidity or long exposure to UV light could break it down and thus open the way for the oxidation.
It seems that a similar oxidation process appeared also on gray-blue dials, but with a different result, transforming the original gray-blue color in a lighter “caramel” one, with different shades probably depending on the original color of the dial.
This rare phenomenon occurred not only on Speedmasters, but also on other models from the same period, as illustrated below.

Audemars Piguet Royal Oak
Ref. 5402 (1972).
Credit: Phillips.

Patek Philippe Nautilus
Ref. 3700 (1980).
Credit: Phillips.

Heuer Silverstone
Ref. 110.313 (1972).
Credit: Shuck The Oyster.

Omega Speedmaster Mk III
Ref. 176.002 (1973).
Credit: Watch Books Only.
Such a process has been observed on some extremely rare Omega Speedmasters’ gray-blue dials.
One of the most incredible example has been seen on a reference ST 105.002-62.
The dial is a Type 2. Gray-blue “Wide Minutes Scale”, which has turned to a kind of “caramel” color. The discolouration, due to the oxidation of the original colour, is extreme and heterogeneous, resulting in a very particular patchwork pattern.
The pictures accentuate the flaws, most of which are invisible to the naked eye. The result on the wrist is a really amazing and unique Speedmaster.

Great Research! I am owning a 105003 with a Perfect (even bettet the one in your article) Type 2 dial and would like to ask for your comment and advice, because I would like to offer it. pictures available after your reply. Thanks and many greetings from Germany.
Thanks for sharing. Could you please send the information and pictures at info@watchfid.com?
Regards.