Convert PDF to Black and White (for free on mobile)

Colored PDFs are eye candy and sometimes essential, for example, if you have pie charts or diagrams that are tricky to read in black and white. But storing everything in color can gobble up your storage space faster than a group of teenagers a pizza—colored image-dense PDFs are 3 to 10 times larger than B&W versions. In this post, we’ll show you how to convert PDF to black and white and how to get colored images ready for B&W printing without losing any detail. Let’s dive in!

How to Convert PDF to Black and White on iPhone for Free

You can convert PDF to black and white super easily and for free in iScanner. Here’s how to do it: 

1. Install the iScanner app. It works on any platform and is free to download and use, and you don’t have to register or sign up. 
2. Open the PDF you need to convert to black and white and tap the Share button.
3. Choose iScanner from the list of sharing options and your PDF will open in the app.
4. Next, tap Adjust at the bottom and then Color.
5. You’ll see the color filters menu—tap B\W or Grayscale. All done! 

You can now share the PDF via email or any messenger, save it to your files, or edit it further if you need to—the app has a super extensive PDF editor that’s free and doesn’t apply branded watermarks to your documents. 

How to Convert PDF to Black and White on Android for Free

1. Install the iScanner app. 
2. Open the PDF you need to convert to black and white and tap the Share button.
3. Choose iScanner from the list and your PDF will open in the app.
4. Next, tap Adjust at the bottom and then Color.
5. You’ll see the color filters menu—tap B\W or Graysale. All done! 

How to Convert PDF to Black and White on Desktop

Regardless of the OS that you use, any PDF software normally allows you to convert PDF to black and white within the printing menu. Here’s how to convert PDF to black and white on your computer:

1. Open your PDF and press Ctrl+P. 
2. Next, go to the printer selection menu and choose “Print to PDF” (the wording can vary depending on the software). 
3. Now, look for a checkbox that reads something like “Print in grayscale” or “Print B&W” and tick it.
4. Finally, press “OK” and choose a location where you want to save your newly converted black and white PDF. 

How to Prepare Your Colored PDFs for Black and White Print Like a Pro

Printing colored documents in black and white might be trickier than it sounds. When you print  B&W the subtle variations in color that provide depth and definition disappear. As a result, highlights can wash out into pure white, and shadows can merge into solid black. This loss of nuance flattens the image, making it harder to distinguish fine details, and sometimes can make human faces look oddly distorted.

The iScanner app has a super simple solution to this problem: a grayscale filter with a slider control. You can easily adjust brightness and contrast by moving the slider because the changes are visible in real time. So before sending your colored document to print, play around with the controller until you get the perfect grayscale image. It’s easy to do and doesn’t cost you anything but your printed documents will look just perfect!

Some Perks of the Black and White Filter

In the context of mobile scanning, a black-and-white filter can come in super handy not only to save storage space. When we scan with mobile devices the lighting is almost never neutral, bright, and even enough. As a result, our scans often end up with a color cast from warm or cold lighting in the room or a shadow of our hand across the page. Neither is great but switching to black and white can remove those altogether. Try it for your scans and check out how much tidier they look!

What if Colors Are Essential but You Need to Remove Shadows and Color Cast from Your Scan?

For such tricky cases, you have several options. One would be to do color correction using special software like Adobe Photoshop or Lightroom, GIMP, or other similar solutions. It would involve a pretty steep learning curve though.

AI Can Do Color Correction for You

iScanner Pro has an AI-powered tool for this purpose. It uses a deep learning algorithm that has been trained to recognize various visual artifacts like color casts, stray marks, halos, shadows, or shine-throughs and remove them while preserving the original colors and turning whites pure white. The feature is super easy to use: all you have to do is tap Polish within the AI filters menu.

Polish isn’t the only AI trick the app has in store—it can also straighten warped pages and text lines, unblur out-of-focus scans, and remove captured fingertips from scans—be sure to check them out!