Complex sentence: It has a compensating effect whereby the developer exhausts itself in areas which require greater development whilst remaining active in less-exposed areas, which has the effect of boosting shadow detail whilst preserving bright highlights.
Split into simpler sentences: It has a compensating effect, whereby the developer exhausts itself in areas which require greater development-such as bright highlights-whilst remaining acting in less-exposed areas. This has the effect of boosting shadow detail whilst preserving bright highlights.