Re: [Leica] Format units question

["Glen M. Robinson" <gmrobinson@imation.com>]

"Henning J. Wulff" <henningw@archiphoto.com> on 08/13/98 07:06:04 PM

Glen Robinson wrote:

>I have always wondered when the rest of the world will abandon the
obsolete
>metric system and move to the modern English system.
>
>
>I sure hope this was written tongue in cheek

You are right, I was mostly teasing.


>As far temperatures go, the whole thing is completely
>arbitrary either way. The digits 3 and 2 make no more sense as a basis for
>temperature measurement than any other digits, and what does 212 have to
do
>with daily weather? This is a non-argument.


Again, the Fahrenheit system is based on the temperature range of the
weather (0 to 100 degrees) that many European people experience during a
year.  The freezing and boiling points of water are irrelevant to this
temperature scale, although these points are now used to calibrate
thermometers (actually the triple point).  But, the freezing points and
boiling points of other materials such as mercury could be used as well for
calibration.  I agree with your point, what does 100 degrees C have to do
with daily weather?

>HOWEVER, lets talk about volumes. How many cc's are in a US fluid oz., in
>an Imperial fluid oz., in a US quart, pint, gallon vs. in an Imperial unit
>of the same name? What a mess!


This is unfair, you are mixing metric and English units. Of course it is a
mess.

My Ph.D. degree is in physical chemistry.  I have been a practicing
scientist for almost thirty years.  We scientists use metric units in our
work, but I still maintain that the English system is often easier to use.
Since virtually all my metric measurements involve decimal points, the
convenience of the ten based metric system is negated.  For example, the
wavelength of the HeNe laser on my interferometer is 632.8 nm.  I measured
the surface roughness of a magnetic tape today to be 11.5 nm and its
porosity to be 0.623 ml/g.  What is simple about that?

In my home darkroom I use English units.  The degree separation in the
centigrade temperature system is too coarse for darkroom use so it is
necessary to use tenths of a degree; this is not necessary with Fahrenheit
degrees.  I dilute my developers in ounces because it is easier to do
mental photographic arithmetic with English units.  For example eight
ounces is easier to divide than 250 ml.  The English system is a human
system.  Again, it is not perfect, but neither is the metric system.

Glen Robinson