Think of the Venus de Milo. Now try to picture her with arms.

“Time Will Tell: Ethics and Choices in Conservation,” which was on display at the Yale University Art Gallery this summer, explored the techniques used and dilemmas faced by conservators in the process of preserving and restoring historic works of art in museum collections.

The gallery’s recently acquired ancient Roman statue of a female figure — dubbed the Green Lady because of the green algae accumulation on its surface — features a right arm that is placed at an awkward angle and out of proportion with the rest of her body. Before the statue can be displayed in its full glory, conservators must remove traces of how conservators altered the piece in later centuries and try to restore its original form.

The task is fraught with dilemmas, and the curators of the exhibition, Ian McClure, Laurence Kanter and Lisa Brody, aim to raise awareness about the difficult decisions conservators and curators have to make in situations where only time will tell the right answer. Later additions made to artworks — such as the sharper black contours added around the figures in the Siennese panel painting “Virgin and Child Enthroned with Four Saints” — can be significant for art historians because they reveal the evolution of tastes and styles over the years. It is therefore controversial to remove all traces of additions. Some of the necessities of preservation, such as a new coat of varnish, can likewise be problematic because they alter the original effect the painter wanted to achieve.

The exhibition explains clearly and comprehensibly the issues of authenticity, historic significance and respect for the artist involved in conservation processes. Nevertheless, conservation jargon — “epoxies,” “refractive indices,” “Raman spectroscopy,” glass that “weeps” or “crizzles” — can intimidate the uninitiated and give the impression that the viewer has stepped into a “CSI: Crime Scene Investigation” episode on art.

The experience is rewarding and educating if the viewer is willing to read the curators’ careful explanations. Yet it is not easy for the untrained eye to discern the alterations or damage in the artwork that the curators cite. It was fascinating to read that a crucifixion scene by Francesco Trevisani previously displayed a lion, but it is impossible to distinguish anything resembling a beast in the painting on display.

The exhibition focuses on a wide range of artwork from mosaics to paintings, from a late French baroque harpsichord to a portrait of Marcel Duchamp made of highly perishable cellulose nitrate plastic. Even the pleasure of viewing this array of rarely displayed items from the gallery’s collection would make the exhibition worth a visit, but the conservation questions that tie the objects together introduce museum-goers to an interesting new perspective. “Time Will Tell” provides an X-ray peek at artwork that viewers are accustomed to seeing fully clothed.