What happened to this case back?

[U5512]

What is going on with this case back? Is it a reflection of something? It looks like a bat wings???.

[Old Expat Beast]

Standard decoration for the era, I believe.

[rq3]

Deleted due to duplication

[rq3]

Originally Posted by U5512

What is going on with this case back? Is it a reflection of something? It looks like a bat wings???.

This is known by various names, usually "jewelling". See
http://www.workingpsychology.com/div.../jeweling.html

It actually served a functional purpose, other than looking pretty. The tiny grooves act as dust traps to keep dirt out of the moving works. Sometimes you will see jewelling on large surfaces, like the dashboards of antique cars, as a strictly decorative effect. It's very difficult to do well (I've done it), and very striking when it is done well.

The "bat wings" you see are strictly a result of the way light is reflected from the jewelled surface. As you move the surface, the bat wings will rotate, which is part of the charm of the process.

[Bob the brush]

Very interesting. Thanks.

[Paul]

Originally Posted by rq3

This is known by various names, usually "jewelling". See
http://www.workingpsychology.com/div.../jeweling.html

It actually served a functional purpose, other than looking pretty. The tiny grooves act as dust traps to keep dirt out of the moving works. Sometimes you will see jewelling on large surfaces, like the dashboards of antique cars, as a strictly decorative effect. It's very difficult to do well (I've done it), and very striking when it is done well.

The "bat wings" you see are strictly a result of the way light is reflected from the jewelled surface. As you move the surface, the bat wings will rotate, which is part of the charm of the process.

Yip. The machined effect (swirling) is called 'damaskeening'. I wasn't aware of the practical use for watchmaking ( serving as a dust-trap) but that sounds quite logical to me.

Good old Wikipedia explains it well ...

https://en.wikipedia.org/wiki/Damaskeening


..... and I'm fairly confident the 'bat-wings' on the OP's pic will simply be reflection