The add-stamp tool always draws the stamp box with a light pink fill and a red border, regardless of user input.
Upload the PDF file to the stamp form.
Adobe's support community confirms a stamp's color cannot be changed through standard menus, since the stamp's designer fixed the colors used for it. changing colours on a dynamic stamp - acrobat and reader | Community
Add StampChange PDF Stamp Color
The add-stamp tool always renders the stamp text in dark red using pdf-lib's rgb helper.
The add-stamp page only sends stampText, the selected pages, and the position to the server, never a color value.
Type the desired stamp text into the input field.
Select the pages where the stamp should appear.
Choose the stamp position from the available options.
Reviewing The Fixed Red Stamp Appearance
Open the downloaded PDF to view the applied stamp.
Compare the stamp border against the light pink fill inside it.
Check the stamp text for the dark red shade.
Continue with Add Stamp Corner Position Options or Add Stamp vs Watermark Difference.
Frequently Asked Questions about Change PDF Stamp Color
Can I get a different stamp color?
Check a separate PDF editor for a custom color picker.
How do I preview the stamp before downloading?
Open the downloaded PDF instead; the form shows no stamp preview.
How do I stamp a second batch of pages?
Repeat the page selection step with a new page range.
Where do I download the finished file?
Download the finished PDF from the results screen.