This is where DStretch comes in. It's a freely available plugin for ImageJ, an image editor that is also free. Dstretch has numerous canned filters that emphasize different aspects of an image. One or more of these is bound to make your vague image much more easy to see. And they areapplied with the click of a button. There is even an option to automatically rotate through the filters. This saves a lot of time and effort, especially if you are dealing with many images.
Here is a pretty good example from a site along the Escalante River.
|Original, Unaltered Image|
|Same Image after DStretch Filtering|
© 2013 Kerk L. Phillips