Quantitative EDS analysis of unknown specimens can be performed with a standard specimen that has known compositions. In this case, the measurement conditions for the unknown specimens should be the same as the ones that were used to obtain the quantified compositions of the standard specimen. These conditions include all the parameters such as the acceleration voltage, specimen-detector geometry, and specimen structure. This method seems crude, but actually, it is relatively accurate in most cases, because the standards are so similar to the unknowns that most effects cancel. However, the most accurate EDS quantifications are normally done on thin specimens in high-voltage (S)TEM mode with calibrated k-factors since K-factors vary from instrument to instrument significantly as shown in the excel file.