How to Watermark Photos — Placement, Opacity, Tiling and Copyright Notice Wording

This article is general information on practical techniques for designing and placing watermarks, not legal advice. For specific disputes or contract issues, consult a lawyer or a specialist body such as the Korea Copyright Commission. Legal references below are to Korean law.

Watermarking is a balancing act between two goals. It should not spoil the photo for viewers, while making things inconvenient for anyone who wants to use it without permission. The right placement and strength depend on your purpose.

Pros and cons by placement

A corner signature is the cleanest but disappears if the photo is cropped even slightly. It's enough if your main goal is attribution, but it does almost nothing to prevent unauthorized use.

Placement that resists removal

The most common ways to remove a watermark are cropping and filling in from surrounding pixels (clone stamp, AI erase). The key is to make both of these hard.

• Overlap the subject. A watermark over empty sky or a plain background is easy to fill by copying the surroundings. If it crosses complex textures like a person's clothing or a product's surface, removal leaves traces.
• Keep it away from the edges. A watermark hugging the edge disappears with a crop of just a few percent. Placing it at least 10% of the long side inward means removing it by cropping would cost important parts of the photo.
• Rotate tiles. Horizontally repeated text is easy to erase line by line, while tiles tilted 30–45° cut across many parts of the subject.
• Semi-transparent is actually harder to remove than fully opaque. A semi-transparent watermark is blended with the photo underneath, so erasing it tends to leave mismatched brightness and color in that area.
• Lower the resolution of public copies. If you only publish copies reduced to about 1,200–2,000px on the long side, even a removed watermark leaves an image that's hard to use for print or commercial purposes.

Choosing opacity, size and color

• Opacity: commonly used ranges are 60–80% for corner signatures, 25–40% for semi-transparent marks over the subject, and 10–20% for full tiling. Tiles are numerous, so they're visible enough even when faint.
• Size: since photos differ in pixel size, setting it as a proportion of the long side rather than an absolute value (px) keeps it consistent across photos. About 3–5% of the long side for a corner signature and 20–40% for a center logo work well.
• Color: use dark text on bright photos and white text on dark ones; if the background is mixed, adding a thin dark outline or a faint shadow to white text makes it readable anywhere.
• Font: fonts with very thin strokes vanish after downscaling and compression. A sans-serif of medium weight or heavier is reliable.

Copyright notice examples

Copyright arises on creation (Korean Copyright Act, Article 10), so a notice isn't a condition for the right to exist, but stating who holds the rights helps deter unauthorized use and makes it easier for people to contact you.

As in the last example, when submitting a copy of an ID card or bankbook, writing the purpose and date over the image makes it hard to misuse elsewhere even if the copy leaks. In this case, it's effective to add it as a semi-transparent tile so the text lightly covers the last digits of the Korean resident registration number or part of the photo (but take care not to hide information the recipient needs to read).

Preparing a logo watermark

When using a logo instead of text, how you prepare the source file determines the result.

• Prepare it as a PNG with a transparent background. A JPG logo with a white rectangular background shows up as a box on the photo. If your logo has a background, remove it first with Remove Background.
• Making both a white version and a black version lets you match bright and dark photos respectively.
• Prepare the logo source at at least twice the resolution you'll place it at so the edges stay sharp after downscaling.

Watermarking many photos at once

If portrait and landscape photos are mixed, a watermark placed at the same pixel size looks large on some photos and small on others. Set the size and margin as a proportion of the long side, and specify the position relative to a corner, such as "bottom right," so it looks consistent regardless of orientation. After processing, pick the brightest and darkest photos and check that the watermark is readable on both.

Methods beyond visible watermarks

• Copyright fields in metadata: EXIF has Artist and Copyright fields that you can fill in from your camera or editing program. However, they're easily stripped during upload, so treat them as a supplementary measure.
• Content Credentials (C2PA): C2PA, whose members include Adobe, Google, Microsoft and the BBC, is developing an open technical standard (Content Credentials) that records an image's origin and editing history in the file. Supporting programs and platforms are increasing, but whether the record is preserved varies by service.
• Invisible watermarks: there are also techniques that hide a signal in the pixels invisibly to the human eye, but how well they survive heavy recompression and cropping depends on the method.

Watermark removal and the law

Article 104-3 of the Korean Copyright Act prohibits, among other things, intentionally removing or altering rights management information (information identifying the work, the author, terms of use and so on that is attached to the work) without legitimate authority. Whether a watermark counts as such rights management information can depend on what it shows and the circumstances, so if an actual dispute arises, get a professional opinion.

Practical checklist

1. Keep the original file separately without a watermark. You can't remove a watermark from a file once it's been added.
2. For public copies, reduce the resolution first, then add the watermark. Doing it the other way around blurs the watermark text as it shrinks.
3. Apply the same proportional settings to many photos in a batch to keep them consistent.
4. Finally, check that the text is readable at a mobile screen size.

The Add Watermark tool places text or a logo in any of 9 positions or as a tile, adjusts opacity, rotation and size, and applies it to many photos at once. Photos are never uploaded to a server, so you can use it even for sensitive images such as ID copies.

Frequently asked questions

Last updated: 2026-09-23

Sources

• Korea Law Information Center — Copyright Act (Korea)
• Korean Copyright Act, Article 104-3 (Prohibition of removal or alteration of rights management information)
• C2PA — Content Credentials