[78-L] a close look at grooves

[Don Cox]

On 22/08/2013, Peter Fraissinet wrote:

> A link to some remarkable photos:
> 
> http://thedig.squarespace.com/thedig/5/pictures-of-the-week-3-detailed-grooves
> 
A good collection, but with no data.

Some, such as the third and fourth, are scanning electron microscope
images. The disc would have to be cut up and a small piece put in the
microscope. An electron microscope cannot take large objects. 

The fourth picture has been around for many years. I would like to know
who originally made it. The stylus must be held in place by something
such as a blob of glue that is outside the frame.

Some of te others seem to be conventional close-up photographs done with
light and a normal camera. Others are uncertain.

The second image seems to show a white or yellow record.

Regards
-- 
Don Cox
doncox at enterprise.net