PDF 转 灰度

Often, yes. Each page is stored as a grayscale JPEG at 90% quality, which is smaller than a color image, so color-heavy files usually shrink. A text-only PDF can grow instead, because its compact vector text becomes a full-page image.

No. Every page is rendered at 2x scale, desaturated, and re-embedded as a JPEG image, so the output is image-based and text can't be selected or searched. If you need searchable text again, run the result through OCR PDF.

Not here. This tool has no options and converts every page using a standard luminance formula. For brightness, contrast, or saturation controls use Adjust Colors, and to convert only some pages, split those out first and merge the results afterward.

No. Grayscale keeps shades of gray, so photos, shaded charts, and highlights stay readable, while true black and white drops everything to two tones; this tool produces grayscale. If you need 1-bit output, PDF to TIFF has a Black & White mode.

The page dimensions are preserved. Pages are rendered at 2x scale, about 144 dpi, which looks fine on screen and is acceptable for office printing, but fine detail won't be as crisp as the vector original.

A grayscale file prints the same on any printer and avoids color charges, and some print shops, courts, and government portals require grayscale submissions. Converting first also shows how colored charts and highlights will look in gray before you print.

They're flattened into the page image. Form fields stop being fillable, comments become part of the picture, and clickable links no longer work.

No. Rendering and the grayscale filter run on a canvas in your browser tab, and the new PDF is assembled there too. Nothing is sent to a server.