The accuracy of the machines is not in question (especially modern ones, which are astoundingly accurate when properly zeroed in). But, any source of old carbon in the ancient environment can affect the amount of C-14 in a sample.Examples: For all of these, and more, reasons, calibration is needed in C-14 dating.I will give you the benefit of the doubt and say that carbon dating is not accurate at dates longer than a few thousand years, but there are so many other observable things which point to billions of years of time rather than a few thousand.
On this site alone there have been statements disputing the constancy of radioactive decay.
One such is FYIIndeed, as can be found in several more articles here:
The main task of the calibration process is to convert this measure into a set of calendar dates by means of a calibration curve.
Users can choose whether they want results as a plot, a short textual summary or both (the plot includes the summary).
A radiocarbon date is represented by a date in years BP (before present, that is before 1950 AD) and a standard deviation, like 2430±170.
The combination of these two values is a numerical representation of a laboratory measure performed on the original organic material.
IOSACal is based on current calibration methods, like those described in [RAM2008].
I read the scientific article on the carbon dating done on the Jericho site written by Bruins and Van Der Plicht.
Furthermore, writing this software from scratch is an alternative way of learning how 14C calibration works, not only in strict mathematical terms, but also from a practical point of view.
IOSACal takes a radiocarbon determination and outputs a calibrated age as a set of probability intervals.
When Kathleen Kenyon came away from her study in the 1950s and essentially announced ‘I see no evidence for the destruction of Joshua here,’ she was basing her opinions, in part, on the new field of radiocarbon dating.