将 PDF 转换为灰度
去除每一页的颜色。
使用方法
上传您的 PDF 并下载结果——每一页都会被渲染为灰度，去除所有颜色。
为什么要将 PDF 转换为灰度？
文件体积更小，黑白打印成本更低——用于存档或内部审阅时，往往不需要彩色照片和高亮。
这会像压缩一样减小文件大小吗？
通常会有一些附带效果——但如果主要目标是达到特定文件大小，请使用“压缩 PDF”；此工具的作用是去除颜色，而非优化大小。
Can I convert back to color afterward?
No — grayscale conversion removes the color data permanently in the output file. Keep your original if you might need the color version again.
Does grayscale conversion affect scanned handwriting or signatures?
They'll render in shades of gray rather than color, but stay just as legible — grayscale only removes hue, not detail or contrast.
Is grayscale the same as black and white?
Not quite — grayscale keeps shades of gray for a smooth photographic look; true black-and-white (1-bit) has no gray at all. This tool produces grayscale, not 1-bit black-and-white.
Will I still be able to select or copy the text after converting?
No. Every page is rendered as an image and rebuilt as a flat JPEG — that's true whether the page was typed text or a scan. The result looks and prints fine, but the text is pixels, not characters, afterward, so it can't be selected, copied, or searched. If you need the text layer to survive, keep your original file and only hand out the grayscale copy for viewing or printing.