In their hour-long presentation, columnists Clay Eals and Jean Sherrard will share how they come up with ideas for the popular photo-history column and the new approaches they are taking to the feature in the wake of a decision by the column’s originator, Paul Dorpat, to retire from the column in 2019. Dorpat completed an astonishing total of more than 1,800 installments during his 37 years at the helm.

In the presentation, illustrated with examples which include sites in North Bend and Fall City, Eals and Sherrard will discuss the column’s formula — starting with an old “then” photo, taking a modern “now” photo from the same vantage and writing text to bring out the details and stories behind the photos.

They also will delve into their methods, which include the use of materials and information from local heritage organizations and the inclusion of people in their “now” photos. They will also cover the innovative touches included in “web extras” provided for each column, including a 360-degree video taken at the “now” photo site, accompanied by an audio rendition of the column’s text.

“Now & Then” can be seen at www.seattletimes.com/category/now-and-then. The same column, with “web extras,” is available each week at pauldorpat.com, where those who are interested can sign up for weekly updates.