Technology makes it easier to keep research logs. My personal preference when doing onsite research is to have the research log be as “process friendly as possible.” For me that means something that models how the records are organized and also models how I work best. Your own mileage may vary.
The probate records for Boston contain a docket entry for each probate/guardianship with references to the specific books in which the estate is mentioned. These different journals are on different rolls of microfilm. I created a research log for my probate work that required minimal typing.
I took a picture of the docket entry for each probate with my phone, right from the microfilm reader. The images aren’t quite as good as digital images made from the microfilm as one of the library’s microfilm printer/scanners, but I didn’t need super good images.
I cropped the image and inserted it in a Word document where then created a table whose lines matched the width of those in the image. Columns were made for the roll number, whether I found the page and copied it, and quick notes. The roll numbers were easily copied from the library catalog, no retyping required.
This sheet served as my research log. It was photographed and put i the same folder as the images I made from the microfilm.
Note: My notes in the final column are not meant to be overly analytical or technically correct. That should be pretty obvious by the use of the phrase “legal stuff.”