1. A method, comprising: identifying, by a computing device, two or more layers in an electronic document; processing a first layer of the identified layers, by performing optical character recognition of one or more images comprised by the first layer to produce a first layer text comprising one or more character strings representing respective images; processing a second layer of the identified layers, to produce a second layer text; combining the first layer text and the second layer text to produce a combined text of the electronic document; identifying, within the combined text of the electronic document, a target character string corresponding, in view of a specified search function, to a specified character string; redacting, from the electronic document, the target character string; visually rendering the combined text of the electronic document; and receiving an input confirming redaction of the target character string from the combined text of the electronic document.