Sandy King (sanking@hubcap.clemson.edu)
Mon, 22 Feb 1999 22:05:20 -0400
Rich Lahrson wrote:
> Let's assume, for my argument, that the cell is reads low at high
>densities, as Richard says. If you are checking against a step wedge,
>you will, at least, be aware of the amount the cell is off, and hopefully
>be able to adjust hegative readings accordingly.
>
> Though, of course, one would prefer one right on. Mine is.
>
>
I acquired a MacBeth TC-504 densitometer several years ago and had not used
the Weston 877 since then. Curious about the current thread on the present
accuracy of the selenium cell I just pulled it out and calibrated the
density reading with my TD-504 at step #10. A subsequent reading of all the
other steps show that they are very close to those of the MacBeth. Because
the readings are analgog on the 877 it is somewhat difficult to read the
higher densities since they are closely spaced on the dial. However, there
is no doubt but that one could do very precise work with this old
instrument.
BTW, my unit came with a nice plexiglass cover that sits nicely over the
top of the densitometer. Does anyone know if these tops came original with
the unit?
Sandy King
This archive was generated by hypermail 2.0b3 on Sat Nov 06 1999 - 10:06:53