I was scanning some old images when the thought of using auto-level for batch post-processing dwelled upon me. So quickly to share my findings.
Auto-Level is not mandatory
Auto-level is not a necessary step during post-processing. When you get a good exposure right from the camera, auto-leveling can introduce artifacts into your images.
Consider Manual Level adjustment instead
In most software auto-level adjustment happens on per-channel basis. Thus red, green and blue channels are all auto leveled. This changes the ratio of these three colors. This step in turn alters, destroys the original image colors and introduces color cast.
There is nothing called batch post-processing. Only go for it if you are willing to get acceptable images. The only way to get the best result is to go the painful way of hand-editing each image individually.
Use Auto Contrast instead
Auto-level attempts to balance the image histogram on per channel basis while giving enhanced contrast. A better way to handle this is to go for auto contrast which does not interfere with color balance.
Tap into the power of Curves
The curves tool is a more powerful tool which gives realistic and appealing results.