Issue and examples: I web-serve irregular-size PDFs such as (well log) https://idahogeomap.nkn.uidaho.edu/Data/Oil_Gas_Scans/1974-02/1974-02_LOG_BHCS.pdf and (map) https://www.idahogeology.org/pub/Technical_Reports/TR-2001-2.pdf that Firefox is displaying as white rectangles via default settings. Background and contingencies: 1.-Of the thousands of PDFs I serve, only a subset is not behaving as expected using Firefox's PDF viewer 2.-I am exploring multiple options to present to my supervisor as 'fixes' 3.-Continually educating our user-base to configure web browsers to display PDF files as expected is not an option 4.-Temporarily refusing user access to data based on browser choice, such as Firefox, is not an option 5.-Forcing PDFs to be delivered by download-only may be an option, but would not be preferred 6.-Reformatting PDFs to display in browsers as expected is an option, but because of budget and time restrictions, would have to be done efficiently *(where my question applies) and delivered without loss of data 7.-All PDFs affected are derived from scans of original documents as TIFF files of various size and resolution. The TIFF files were discarded, and re-scanning is not an option 8.-PDF files or pages in files that do not render as expected are derived from a single scanned image Request: I would appreciate being privy to exactly what Firefox requires to display PDF files as expected without user interaction with browser settings: For example, download and display of the documents linked above in a new installation instance of Firefox on contemporary Windows, Mac, and Linux (canonical FF install) desktop environments (provided there is no disparity in PDF 'minimums' or 'lowest common denominator' for rendering). Possible PDF properties that may influence if Firefox will render a PDF or not are below. For any of these that could impact a successful render, or others that will but are not listed, I would appreciate knowing the working range of property attributes. Please be specific about units, for instance resolution or width as dots per inch or mm, points, pixels, etc. -Metadata in header (? -probably a long shot . . . ) -File size -MediaBox (CropBox, BleedBox, etc.) size(s) as applicable -Resolution -width -height -? Please don't hesitate to provide 'too much' information! I intend to recursively test each PDF served against the parameters Firefox likes, create an altered copy for PDFs that fail, then push the new filenames to server databases and web. Thank you very much in advance, Christopher