Lamps and sunlight were both used to make the images here. Note the distortion in the proportions of the portraits. The distortion is in the long axis of the scanner bed and due to what is called "parallax". The scanner does not scan the full width of the bed. Optics are used to gather light form the sides. One website has a brief article on how to due stereoscopic images with a scanner by taking advantage of the phenomenon. A simple shrink/resize/resample of the long (height) dimnension of the scanner image will create the illusion of natural proportions. That was done in the images below except for the lower left image.. The apparent linear stretch is reminiscent of a map projection. I'm sure a mathematical formula can be used to restore the proportions, I have no idea what the formula is though, and the item is not high on my list of priorities. IF and when I get the formula I may write a program to restore the proper dimensions to a scanner image.

Find an image editor/browser such as Irfanview or XnView that allow resizing of width and height independently. Look for an Aspect Ratio checkbox.

My particular scanner had the lamp removed for other work when these were made. The orange color indicates sunlight was used. The scanner is sensitive to local color reflections. What appears as sunlight is, if indirect as it should be, will contain colors from one or more reflecting surfaces. Taking the scanner onto my front porch (two white walls) helped act as a color correction. Trial and Error result in an acceptable image Histogram adjustment is useful but I've found only one lightweight image browsing application that does histogram editing and the owner has removed the application from the intwernet.