Significant tonal adjustment. At first glance, doesn't appear to be significant editing -- but based on the history the Purdue image has gone through, it very well may have had the blacks touched up.

I am more intrigued by the phrase "slide scan," however.

Why would university archives in 1969 have high-quality color photographs of the Earth from lunar distance? (And, no, it doesn't look at all the same photographed in multiple passes and stitched from a satellite in LEO!)

What does the OP think was out at lunar distance making and returning color slide film?