Text over image -> what effect is this?

hello all,

i have on this website: https://quartz-portfolio-template.webflow.io/

an effect that i would like to recreate. When hovering over the respective case (section work) an image appears behind the text. The text gets then an effect whereby one sees the picture somewhat through (negative effect?). Which effect is it and how can I implement it with Webflow? Ideas? :))