Converting your PDFs to black and white can save you storage space and money. Black and white -- or grayscale -- is a range of gray shades from white to black, which appears colorless on your computer and when you print. It reduces the size of your PDF and can save color ink when you send your PDF to print.
If you have Adobe Acrobat Pro you can convert your PDFs from color to grayscale on your computer, but it costs a monthly fee. First, open the color document you want to convert and save a copy. Next, find the Tools pane, click the "Print Production" panel and select "Convert Colors." To convert the entire page to grayscale, choose the default, "Any Object for Matching Criteria." Alternatively, you can select an option from the Object Type drop down menu. Next, for Conversion Attributes, select "Gray Gamma 2.2." Now click "OK," review the warning message that this operation cannot be undone, and select "Yes."
For Mac users, Preview is a free, built-in option for editing PDFs. Open your document with Preview and choose "Adjust Color" in the Tools menu. In the Adjustment Tool panel slide the "Saturation" scale all the way to the left. This removes all color, making the document appear black and white. You can adjust other levels to improve the grayscale of your PDF. If you are having trouble adjusting the color this way, try another option. Choose "Save As" in the File menu. If you don't see this option, search for "Save As" in the Help menu. For the Quartz Filter select either "Black & White" or "Gray Tone." If you don't see the changes in the document you currently have open, close it and reopen the document. It should now appear black and white or grayscale.
If you are not a Mac user, try an online program to convert your color PDF to grayscale. One free Web program allows users to upload a color PDF and download it again in black and white. Go to greyscalepdf.com and upload your PDF. Next, click "Convert," and wait for the program to process. Now click "Download" and save your new black and white document.
PuzzleFlow Online is another free Web-based service that allows you to edit PDFs online. To convert your color PDF to grayscale, visit PuzzleFlow Online and select "Convert to Grayscale." Unlike Greyscale PDF, for this service you must accept the Terms and Conditions and enter your email address. Also different, you can upload up to 10 files at a time. Choose your documents using the + button and click "Upload and Process." The program will show a list of your documents and automatically download your new PDF when it finishes processing. When you are done, clear the queue or wait 24 hours and the files are automatically removed.