Because files stored within TSDR must be compressed to avoid possible bandwidth storage issues at the USPTO, both incoming items (e.g., specimens) and outgoing items (e.g., examining attorney's evidence) are often not easily read. To help resolve this problem, it is recommended that you change your default display setting to at least 100%, by following these steps: (1) open your PDF reader (e.g., click on the icon for Adobe Acrobat, Foxit, Nitro, or other reader); (2) from the Toolbar, click "Edit" and then "Preferences;" (3) Under "Categories," select "Page Display;" (4) Look for "Zoom" under "Default Layout and Zoom." The setting here most likely is "Automatic," but you can use the pulldown to increase to any size.
Once you have changed the "Zoom" setting, you can proceed to view the desired item in TSDR in a larger size: (1) When you first click on a specific "Document Description" link in TSDR (e.g., "Specimen"), you will see a blue "Download PDF" button in the upper right---click on this button; (2) when the download is complete, you will be prompted to open the item---when opened, it will be at the larger size, i.e., whatever size you selected for your "Zoom" setting; (3) If trying to view attachments to an Office action in the larger size, do not try to access the attachment directly; instead, again use the "Download PDF" button to download the entire Office action, and then once opened, scroll to the bottom of the Office action where the attachments are imbedded.
NOTE: If you do not wish to change your overall "Zoom" setting, it is possible to change this feature on an individual basis. Simply download the item as indicated above, and then change the setting for this specific item using either the pulldown or the (- +) button, as appropriate for your particular browser.