Most watermarks fail in one of two opposite ways: so subtle that a 10-second crop removes them, or so loud that the photo becomes an ad for the watermark. The fix isn't taste — it's a handful of numbers.

Opacity: 25–40%

Full-opacity text reads as vandalism. At 25–40% opacity a watermark stays legible over both light and dark regions while letting the image show through. Go toward 40% for busy, textured photos (markets, foliage) and down toward 25% for clean studio shots. Pure white or pure black text at moderate opacity outperforms colored text almost everywhere.

Position: Not the Corner

The bottom-right corner is where every thief looks first, and cropping 5% off one edge costs them nothing. Two placements actually survive:

  • Across the subject. A single diagonal watermark crossing the part of the image people actually want — the face in a portrait, the product in a listing — can't be cropped away without destroying the value of the theft.
  • Tiled across the whole frame. Repeating small text at a 30–45° angle over the entire image is the standard for proofs, previews and anything sent before payment. It's aggressive by design; use it when protection matters more than presentation.

Size: 3–5% of Image Height

A watermark should be readable at the size the image is actually viewed. Text height around 3–5% of the image height works for single marks (roughly 40–90 px of font on a 1080–1920 px photo); tiled marks can go smaller because repetition does the work.

Angle: 30–45° for Tiles

Diagonal tiling defeats naive clone-stamp removal far better than horizontal rows, because it crosses more texture boundaries. For single watermarks, horizontal (0°) or matching a natural line in the composition looks most intentional.

Test the Settings Before Committing a Batch

The advantage of a live-preview browser tool like ImageHow's Watermark Image is that opacity, size and angle are sliders — adjust until the mark is visible in a thumbnail *and* tolerable at full screen, then apply the same settings across the set for a consistent, professional look. One more habit: keep the unwatermarked originals archived separately; the watermark is for the copies that leave your machine.