The purpose of the study is to observe the effect of the level of luminance on the emotional evaluation (positive, negative, neutral) in electroencephalography (EEG) records. EEG records of 31 healthy volunteers were used in the study. Features were obtained from these records by using Principle Component Analysis (PCA) method. As a result of the analysis of the features, it was observed that the increase in luminance level during emotional evaluation reflected to the EEG activity and there was a difference that could be observed between the responses given by the brain to bright images with increased luminance levels and the responses given by the brain to original images using the angle difference between the principle components. In addition, the emotional evaluation states and the electrode regions in which this difference is apparent clearly are also examined. It is thought that the results of the research can include in the methods an important parameter such as luminance in the related electrophysiology studies.