Watch folder and history
Two features save clicks when you handle labels all day: a watch folder that picks up new downloads for you, and a print history that lets you reopen what you printed.
Watching a folder#
Marketplaces and carriers save labels as PDFs in your Downloads folder: a Vinted, eBay, Etsy, Poshmark, Depop, or Mercari order label, or one from USPS, UPS, FedEx, or DHL. With a watch folder, ThermalPrint adds each new one to the print queue as soon as it appears, so you can download labels in your browser all morning and print them in one go. Company names are used only as examples of where labels come from; ThermalPrint is not connected to them.
Turn it on#
- Open Import & Convert and expand Watch a folder.
- Press Choose folder… and pick the folder, for example Downloads. Watching starts right away.
- Download a label. Within a couple of seconds it joins the queue, ready to review.
Untick Watch for new labels to pause, or press Clear to forget the folder. ThermalPrint remembers the folder and the on/off choice for next time.
To keep the folder tidy, also tick Move printed labels to a Processed folder. After a label prints, it is taken out of the queue and moved into a Processed subfolder, and the next label in the queue is shown in its place. The queue count, the Label X of N counter, and the Previous and Next buttons update to match. This keeps Downloads from filling up with labels you have already sent out.
Undo, and printing a label again#
When labels are moved, the message box offers Undo for 12 seconds. Undo moves the files back into the watch folder and adds them to the queue again; it never overwrites a file that has the same name, and it is not offered while the app is busy. To print an older label again at any time, press Add from Processed… in the Watch a folder section. It opens the file chooser in the Processed folder; labels you add that way are not moved again. Print Center's recent list follows a file to its new place.
A different printer for watched labels#
If your watched labels always go to one printer, for example your thermal printer for marketplace and carrier labels while ordinary documents go to a laser printer, pick it under Printer for watched labels. Whenever a label from the watch folder (or its Processed folder) is shown, the app switches to that printer, using the media and settings you saved for it the last time you used it, and says so in a message. Leave it on Current printer to never switch. A queue that mixes labels from several places is printed with the printer selected when you press Print all.
What is picked up#
| Rule | Details |
|---|---|
| File types | PDF, PNG, JPEG, TIFF, BMP, and WebP, in the chosen folder itself (not its subfolders). |
| Old files | Files that were already in the folder when you turned watching on, or chose the folder, are ignored. Only new files are added. |
| While ThermalPrint is closed | Labels saved in the folder while the app was closed are added when it opens, and a message says how many. ThermalPrint remembers when it last checked the folder (about once a minute while watching), so only files saved after that are added. With Print labels automatically on, they print like any new label, each after the Cancel countdown. |
| Downloads in progress | A file is added only after its size has stopped changing, so a half-downloaded PDF is never opened. Temporary names such as .crdownload are skipped. |
| Skipped files | Empty files, files over 50 MB, hidden files that start with a dot, and shortcuts (symbolic links). |
| Each file once | A file is added a single time, even if you remove it from the queue. If you delete or move the file and later save a new one with the same name, the new file is added. |
| Printed labels | Tick Move printed labels to a Processed folder and each label you print from the watch folder leaves the queue and is moved into a Processed folder inside it. A file with the same name there is never overwritten; the new one is saved as label (2).pdf. Labels you added from elsewhere are not moved, and a multi-page PDF is moved after its last page prints. The option is off by default. |
| Where you are | If you are on Home or Import & Convert, the app switches to the queue. If you are in the Designer or Print Center, it stays put and the status bar says how many labels are waiting. |
Unless you turn on Print labels automatically, the watch folder only adds labels to the queue. It never prints by itself, and you review each label and press Print. Automatic printing is off by default.
While watching is on, a green dot followed by Watching and the folder's name stays visible at the top of the sidebar, even when the Watch a folder section is closed. If the folder cannot be read later, for example because a drive was unplugged, watching keeps trying: a red message says what is wrong, and when the folder is readable again a message says so and new files are picked up. If the folder cannot be opened when you choose it or at startup, watching is switched off, the red message stays, and Turn watching back on restarts it once the folder is available. The Snap can read your home folder and folders you pick in the file chooser; see Using the Snap.
Printing labels automatically#
By default the watch folder only adds labels to the queue, and you press Print. If you print many labels a day, you can let ThermalPrint print them for you. It is off until you turn it on, and your choice is remembered.
Turning it on#
- Choose a watch folder and tick Watch for new labels.
- Tick Print labels automatically under Watch a folder. The first time, a short warning explains that every label that lands in the folder will print by itself, and Turn on confirms it. If the folder looks like your Downloads folder, the warning says that an invoice or any other PDF saved there could print too.
- Optionally set Only files named and Most per minute (below).
Use a folder just for labels. Automatic printing works on whatever lands in the folder, so a folder that only receives labels, not Downloads, is by far the safest. Decide in your browser where label downloads go, and watch that folder.
What prints, and what waits#
| Rule | Details |
|---|---|
| Only labels that need no review | The app already knows when its crop detection is unsure. Only a label whose crop needs no review prints by itself. A label that does need a review joins the queue as usual, and a message says it was not printed automatically. Skip review for automatic crops does not change this rule. |
| Only single-page files | A PDF with several pages waits for you in the queue, because it is not clear which page is the label. |
| Only files that match the filter | Only files named takes names or patterns, separated by commas: * stands for any letters and ? for one letter, and capital letters do not matter. For example label*.pdf, order-?.png. Leave it empty to allow every file. Files that do not match are added to the queue as before, quietly. |
| Each file prints once | A file is never printed automatically twice in a session, and files that were already in the folder when you turned watching on are never printed. Labels saved while the app was closed count as new: they print when it opens, after the countdown, so press Pause auto-print if you do not want that. With Move printed labels to a Processed folder on, a printed label is also moved out of the folder. |
| A ready printer | A printer and media must be chosen. If they are not, the label stays in the queue and the message says what is missing. With Printer for watched labels set, the app switches to that printer first. |
| A clipped label never prints | If the label would be cut off, the print is blocked, exactly as when you print by hand, and automatic printing pauses. |
The countdown, Cancel, and Pause#
- A 5-second countdown with Cancel. A message in the corner, such as Printing label-1049.pdf · 3 s, gives you a last chance to press Cancel. A cancelled label stays in the queue so you can print it by hand.
- Pause auto-print. A button beside the green Watching line stops automatic printing at once; labels waiting for their countdown are cancelled and stay in the queue. The line shows auto-print on or auto-print paused, and Resume auto-print starts it again. The pause is not remembered: if automatic printing is on, it is running again the next time you start the app.
- Most per minute. A burst of files cannot print more labels than this in one minute (from 1 to 60, default 10). The rest wait their turn, and a message says so. This keeps a mistake from using up a roll.
- A problem pauses everything. If a print fails, or the printer or media goes missing, automatic printing pauses itself and a red message says why, instead of repeating the problem on every file. The label stays in the queue. Fix the cause and press Resume auto-print.
Records#
Every automatic print is listed in Print Center under Recent prints, like a print you made by hand, and in the Messages list beside the status bar. With Move printed labels to a Processed folder on, the label then leaves the queue and its file moves to Processed, with the usual Undo, without disturbing the label you are looking at.
Drag and drop#
You can always drop files onto the window instead: PDFs and images go to the Import queue, and a single .thermalprint file opens in the Designer.
Recent documents#
The Home screen lists files you opened recently (up to eight). Pick one to open it again. These are remembered as file names and locations, not copies of the files.
Print history#
ThermalPrint keeps a list of your last 50 successful prints, shown in Print Center → Recent prints. Each entry records the time, printer, label name, and copies.
| What you printed | What Open does |
|---|---|
| A design | Reopens it in the Designer as an unsaved copy of what was printed, even if you never saved it (unless it contained very large images, in which case the saved file is used). |
| An imported label | Adds the original file back to the queue in Import & Convert. If the file moved or was deleted, you are asked to add it again. |
| A batch | Reopens the design you used. Choose the CSV again to repeat the batch. |
Opening an entry never prints. History is saved in a small file in your settings folder (see Settings and privacy), and Clear history deletes it.