No techniques that add, relocate, replace, or remove pictorial elements except by cropping are permitted. Techniques that enhance the presentation of the photograph without changing the nature story or the pictorial content, or without altering the content of the original scene, are permitted including HDR, focus stacking and dodging/burning. Techniques that remove elements added by the camera, such as dust spots, digital noise, and film scratches, are allowed. Stitched images are not permitted. All allowed adjustments must appear natural. Color images can be converted to grey-scale monochrome. Infrared images, either direct-captures or derivations, are not allowed.