For cameras, with enabled server-side object detection events can be searched by object colour. To search objects by color open menu events. To add colour filter to your search results first select the object type you are looking for. You can even choose multiple object types simultaneously, in this case all objects with the selected color will be included in the list and if there are more than one object in the scene then just one object has to have a selected colour.
Once the first object type is selected the colour selection panel will appear, allowing you to choose one or more colours of interest to filter events by this colour/colours. If multiple colors are selected then objects that contain at least one of the selected colours will be included in the list.
To learn how to use color search please visit this page.