黑边和边缘污渍

扫描时稿台比纸大，四周会出现纯黑或深灰边。复印件则常在四边有一条脏灰，中间是正常的。

两个功能不要混

「去黑边」针对四周明显的深色边框，适合扫描仪多出来的黑框。它会裁掉被当成边的区域，裁掉的内容不会留在结果里。

「去边缘污渍」针对贴着纸边的灰带、指印和复印脏边，尽量不动纸心。没有一条清晰黑框、只是四边发脏时，用这个，而不是去黑边。

在体验页怎么试

在去污体验里先选一个功能再运行。去黑边后如果页边的字被裁掉，说明检测把文字当成了边。这页不要用去黑边，改试去边缘污渍或保留原图。两个可以接连跑，但每跑一次都要看四边的字还在不在。

跑完要核对

四边是否还有半个字、页码或装订线。去边缘污渍是把边缘脏色往白里推，边缘上的浅色注释可能变淡。整页发黄不是边缘问题，请看发黄和脏背景。

Black borders and edge stains

If the scanner glass is larger than the paper, the scan grows a black or dark gray frame. A photocopy more often has a dirty gray band on the edges and a normal middle.

Do not swap the two tools

Crop border is for a clear dark frame, the extra black edge from a scanner. It cuts away the area it treats as border. What is cut is gone from the result.

Border stains is for a gray band, fingerprints, or copy dirt sitting on the paper edge. It tries to leave the middle alone. If there is no sharp black frame and only the edges are dirty, use this, not crop border.

How to try it

On the cleanup demo, pick one tool and run. If crop border slices off letters at the edge, the detector treated text as border. Do not use crop border on that page. Try border stains or keep the original. You can run both, but check the edges after each run.

What to check afterward

Half-cut letters, page numbers, or a binding line on any side. Border stains pushes edge dirt toward white, so a light note on the margin can fade. A yellow page is not an edge problem. See yellowing and dirty backgrounds.