The short answer
Drop one or more PDFs on the tool below. With Keep text selected, each file is converted and the row says either Fully gray, text kept, or which pages still contain some color. Download the file or all files as a ZIP. If a file still has color and you need it fully gray, switch to Pages as images, choose the quality and tone, and the files are converted again.
If you only want to print one copy in black and white, the print dialog of your system may also offer a grayscale option. A converted file is better when you send the document to someone else, upload it to a portal that requires black and white, or print it many times.
Try it here: PDF to black and white
Open the full tool pageTwo methods, two results
Keep text edits the colors inside the PDF. Text colors, lines, fills and simple gradients are rewritten as gray using the standard brightness formula, so a dark red becomes a dark gray and a light yellow becomes a light gray. Color images are converted to gray, palettes are converted entry by entry, and the colors of comments and link borders are changed too. The text remains real text: you can select it, search it and copy it, and it prints sharp.
Pages as images draws each page as a picture at 100, 150 or 300 DPI and replaces the page with that picture in gray, or in pure black and white if you choose that tone. Nothing colored can survive this, but the text becomes part of the image and can no longer be selected or searched.
| Keep text | Pages as images | |
|---|---|---|
| Text | Stays selectable and searchable | Becomes part of an image |
| Result | Gray, with a check for any remaining color | Always fully gray or black and white |
| File size | Usually the same or smaller | Often larger for text documents |
| Best for | Reports, slides, invoices, forms | Scans and files that keep some color |
Why some color can remain
PDFs describe color in many ways. Ordinary colors, which cover most documents, are simple to convert. Some designs use special print inks with their own names, complex gradients built from mathematical functions, color meshes, or images stored as JPEG 2000 or in CMYK print colors. Converting these exactly would mean redrawing them, which this method avoids so that nothing else on the page changes.
Instead, the tool checks its own work. After converting, it draws every page and looks for areas of real color, ignoring the faint color fringes that screens add around text. If it finds any, the row lists the pages. You can then decide whether a small colored logo matters, or switch to Pages as images for that file.
Grayscale or black and white
Grayscale keeps the shades: photos stay recognisable, charts keep their contrast and light backgrounds stay light. Black and white, available with Pages as images, turns every pixel either black or white. That is ideal for scanned letters, contracts and forms, because gray paper and scanner noise disappear and the file becomes small, but it is a poor choice for photos, which turn into harsh black areas.
For the quality, 150 DPI suits normal text, 300 DPI suits small print or documents you will print professionally, and 100 DPI keeps files small for screen reading.
Check charts before you send
Colors that look different can turn into nearly the same gray. A chart with a red and a green line, or a pie chart in blue, purple and orange, may be hard to read after conversion because these colors have similar brightness. Open the converted file and check every chart. If two series look the same, change the colors or add patterns or labels in the original document and convert again. Dark text on a colored background box is another case to check: a dark blue box with black text can become a dark gray box where the text is hard to see. Lighter background colors in the original solve this.
When to use grayscale
- Printing many copies on an office printer that charges more for color pages.
- Job portals, courts or authorities that ask for black and white documents.
- Archiving scans where color adds size but no information.
- Checking that a design or chart still works for people who print in gray.
- Saving color toner when you print drafts.