The intention of this paper is to contribute to the discussion on the characterization methods for laser components within the framework of CHOCLAB. We report on absorption measurements performed with a highly sensitive laser calorimeter at the wavelengths 532 nm and 1064 nm. Several types of sample holders have been tested for their performance and the results were studied with special regard to the influence of scatter light and other signal distortions. For the evaluation of the temperature data, different methods are employed and compared. Based on our practical and theoretical investigations, the practicability of the ISO/FDIS 11551 for calorimetric measurements in the visible and near infrared spectral range is discussed and possible refinements are suggested.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.