Calibration Techniques and Strategies for the Present and Future LHC Electromagnetic Calorimeters

This document summarizes an invited talk on ``Calibration Techniques and Strategies for the Present and Future LHC Electromagnetic Calorimeters'' at the Calorimetry for the High Energy Frontier (CHEF) Conference in Lyon, France in October 2017. It describes the different calibration strategies and techniques applied by the two general purpose experiments at the LHC, ATLAS and CMS, and discusses them underlining their respective strengths and weaknesses from the view of the author. The resulting performances of both calorimeters are described and compared on the basis of selected physics results. Future upgrade plans for High Luminosity (HL) LHC are briefly introduced and planned calibration strategies for those new detectors are shown.