Import and Convert
Import & Convert turns a downloaded label into something your thermal printer can print at the right size. The label file you open is never changed; ThermalPrint works on a copy in memory.
Where labels come from. Most people import the PDF that a marketplace or carrier gives them after a sale: for example a prepaid label from Vinted, eBay, Etsy, Poshmark, Depop, or Mercari, a label bought from USPS, UPS, FedEx, or DHL, or one from a shipping service such as Pirate Ship, Shopify Shipping, or Amazon. These files are often a full A4 or Letter page with the label in one corner, followed by instructions, a receipt, or a packing slip. ThermalPrint finds the label and crops the rest away. The examples in this manual use these names only to describe where labels come from; ThermalPrint is not connected to, or endorsed by, any of these companies, and it does not buy postage.
Adding labels#
You can add labels three ways:
- Press Add labels… or Ctrl+O and choose one or more files. Alt+← and Alt+→ move between queued labels.
- Drag files from your file manager onto the window.
- Set up a watch folder so new downloads appear by themselves. Tick Move printed labels to a Processed folder there to have each printed label leave the queue and move into a
Processedsubfolder.
Supported files: PDF, PNG, JPEG, TIFF, BMP, and WebP. Each page of a multi-page PDF becomes its own entry in the queue. Files can be up to 256 MB and 45 megapixels. If a PDF is encrypted or damaged, export it again from the place you got it.
The print queue#
Everything you add joins the print queue. The queue shows Label 1 of 3 with previous and next buttons, a strip of small thumbnails, and a Queued labels list.
The thumbnail strip appears when there are two or more labels. Click a thumbnail to show that label; the selected one is highlighted and hovering shows its position and file name. A label gets its picture the first time it is shown, so until then its button shows its number. The counters, thumbnails, and the Previous and Next buttons always follow the queue, including after a label is printed and removed.
| Control | What it does |
|---|---|
| Previous / next | Move between labels in the queue. |
| Move up / move down | Change the printing order. |
| Remove (trash) | Take the selected label out of the queue. The file itself is not deleted. |
| Print all N labels in order | Send every label to the printer, one after another, in queue order. See below. |
| Printed labels (with Move printed labels to a Processed folder on) | After you print, the label leaves the queue, its file moves to the Processed folder inside your watch folder, and the next label is shown. The counters follow along. See Watching a folder. |
| Page box | For a multi-page PDF, jump to another page. |
Each label remembers its own crop, extraction mode, and review state. Recent file names are remembered, so you can reopen files from Home.
Keeping the queue between sessions#
The queue is saved as you work. If you quit or the app closes unexpectedly with labels still in the queue, the app still starts on Home, and a Restore your last queue? card appears above the two start cards (the same prompt also shows at the top of the Import & Convert sidebar until you choose). Restore opens Import & Convert, puts the labels back with their crops, and shows the first one; Discard forgets them. Restored labels must be reviewed again before you print (unless Skip review for automatic crops is on), and files that have been moved or deleted since are left out. Until you choose, the saved queue is kept and not overwritten.
Options for Print all#
| Option | What it does |
|---|---|
| Skip review for automatic crops | Off by default. When on, labels you add from then on count as reviewed, so Print all does not wait for you to check each crop. Use it only for labels whose layout you trust, such as the same marketplace's or carrier's labels every day (for example a stack of Vinted or eBay labels that always look the same). Check a label from a new source by hand first. Labels already in the queue keep their review state, and you can still review any label by hand. The Print button still stays disabled if a label would be clipped. |
| Keep going if a label fails | Off by default. When on, a label that fails (a file that can no longer be read, a layout error, or a printer error) is skipped and the rest are still printed. Skipped labels stay in the queue and the message lists how many failed and why the first one failed. This suits a busy day of marketplace orders, where one bad file, such as an expired USPS or UPS label that cannot be opened, should not hold up the other twenty. |
Step 01: Extract#
Most carrier PDFs have a label plus instructions, a receipt, or a lot of empty space. Extract chooses which part to print.
Automatic#
ThermalPrint looks for printed content and proposes a crop with a small safety border. When one region looks like a label and another looks like an instruction block, it keeps the label and drops the instructions. If several regions look equally likely, it keeps the whole page until you choose. A Queue all N detected regions button turns each region into its own queue entry, useful for a sheet that holds several labels. Automatic is layout analysis, not a carrier-specific recognizer: always review it.
Manual#
Switch to Original / crop in the preview. Drag on the page to draw a crop, drag inside it to move it, and drag a corner to resize. The crop is described on the original page, before any rotation. Reset to entire page starts over.
Full page#
Prints the whole page. Use it when the file is already a label or when the edges are unclear.
Reviewing the crop#
When a crop leaves something out, ThermalPrint asks you to confirm it before you can print. Check the address, tracking number, carrier marks, and the empty margin (the quiet zone) around each barcode, then tick I checked the crop and barcode edges (or Reviewed above the preview). Print all needs every queue entry to be reviewed.
Step 02: Paper and layout#
| Setting | What it does |
|---|---|
| Size presets | 4 × 6 in, 4 × 4 in, 2 × 1 in, and 100 × 150 mm. 4 × 6 inches is the standard shipping label. |
| W and H | A custom width and height in millimeters (10 to 500). |
| Swap portrait / landscape | Swaps width and height. |
| Rotate | Turns the label 0°, 90°, 180°, or 270°. Use it when your printer feeds labels sideways. |
| Fit within paper | Scales the crop to fill the printable area while keeping its proportions. The usual choice. |
| Actual size | Uses the source's real physical size. Images without a reliable size are treated as 300 DPI. |
| Custom scale | A percentage from 10 % to 400 % of the actual size. |
| Margin | Empty space around the label, 0 to 20 mm. |
| Black-and-white threshold | Turns every pixel fully black or fully white. Off by default because it can damage thin barcode bars. Turn it on only if a gray label prints faintly, and test the barcode. |
Blocked on purpose. If the content would be cut off (clipped) at the chosen size, printing and exporting are blocked and a warning explains why. Use Fit within paper, rotate, reduce the scale, or choose larger paper.
ThermalPrint also warns when the label is shrunk a lot (small text and barcode bars can become unreadable) or when low-resolution pixels are enlarged. Enlarging cannot restore detail that is not in the file.
Step 03: Print and export#
- Choose the printer. A short hint under it says whether it looks like a label printer. This is a best guess from the name and media, not a guarantee.
- Choose the media size the printer advertises, matching the stock you loaded. See Print Center for how media works.
- Optionally open Advanced driver resolution to pick a resolution your printer offers.
- Set the number of Copies.
- Check the line under the readiness message, for example Will print: 1 × 101.6 × 152.4 mm · Printer name · 203 dpi. It shows exactly what will be sent, so a wrong copy count, size, or printer is easy to spot.
- Press Print label at the bottom of the sidebar, or the green Print button above the preview, or Ctrl+P. Use Ctrl+Enter to print and move on to the next label in the queue.
Not sure about the paper or alignment? Load plain paper and print the alignment test first; see Alignment and printer profiles. The readiness message above the Print button (Ready to submit, or a warning about the media size) appears before anything is sent.
If the label came from your watch folder and Move printed labels to a Processed folder is ticked, a successful print also moves the file into Processed and shows the next label. Labels you added by hand from other folders stay where they are.
The PDF and PNG buttons save the finished label as a file instead; see Exporting. Job status asks the printer system what is waiting.
The Print button stays disabled until the label has rendered, the crop is reviewed, a printer and matching media are chosen, and nothing is clipped. The status bar and the notice in Print Center say what is still missing.
The preview#
The right side shows the label two ways. Use the buttons at the top:
- Original / crop shows the whole source page and your crop, for drawing and adjusting.
- Thermal label shows the final result at print resolution, exactly as it will be sent.
- The zoom buttons and Fit change the preview size.
Under those buttons, a second row keeps the everyday actions next to the label, so you do not have to scroll the sidebar to find them:
| Control | What it does |
|---|---|
| Previous / next, with Label 2 of 5 | Move through the queue. They appear when there are two or more labels, and match the buttons in the sidebar and Alt+← / Alt+→. |
| Reviewed | The same check as I checked the crop and barcode edges in Step 01. Tick it once you have looked at the crop; the Print button stays disabled until you do (unless Skip review for automatic crops is on). |
| Print (green, with a printer icon) | Prints the current label, exactly like Print label in the sidebar and Ctrl+P. While it is unavailable, point at it to read why: for example Tick Reviewed once you have checked the crop, Choose a printer, Choose printer media, The label would be clipped, or The preview is still being prepared. |
The row appears once a label is open. Print all stays in the sidebar, next to the queue, on purpose: printing every label in one click is easy to do by accident, so it is not on the toolbar.
Printing several labels#
Add all the files, review each one, then press Print all N labels in order. The labels are submitted one after another in queue order. Unless Keep going if a label fails is ticked, the batch stops at the first problem (a file that can no longer be read, a layout error, or a printer error) and tells you how many were sent. With that option on, only the failed labels are skipped and stay in the queue. Print all uses the printer that is selected when you press it. Paper size, resolution, rotation, margins, scale, copies, printer, and media are shared by the whole batch.
Submission order is not a promise about physical printing. Use Job status and look at the printer to confirm what came out.
If you want to print many different values on one design, such as a list of customers, use Batch printing from CSV instead.
Tips for good barcodes#
- Leave a clear margin (quiet zone) on both sides of every barcode.
- Keep thresholding off unless you need it.
- Prefer Fit within paper on a source that is already label-sized.
- Scan a test label with your phone or scanner before printing a roll. ThermalPrint does not read imported barcodes or measure print quality.