Depending on which filters you use, only light associated with specific wavelengths — red, green, blue, or even infrared — will hit the photographic plate. When you add the images together, associating each filtered image with either R, G, or B, you get a full-color image.
Some imagers use small, modified video cameras — or webcams — to acquire data. So a caption that reads “best 50 of 600 images” means the imager used software to select the best 50 images out of a continuous batch of 600 obtained with a webcam. One frame differs from another in clarity because our atmosphere is in constant motion.
For LRGB (and similar) images, each exposure is saved as a separate file that software such as Adobe Photoshop can interpret. Software such as Registax combines multiple webcam exposures into a final image. Each imager has his or her own way of processing exposures to highlight different aspects of the photographed object. MICHAEL BAKICH, PHOTO EDITOR