Nowadays, most of the pictures we publish online or share with others come from our smartphones. Whenever it has personal information like debit card numbers, addresses, phone numbers, passwords and other sensitive information, you can just jump into your iPhone’s markup tools to darken the text before sharing. However, using a digital marker may not be enough to hide everything.
When you use markup in iOS, be it from Photos, Files, or another app, or straight from the screenshot editor, you may be only partially hiding data that you want to keep secret. The marker, also known as a highlighter, is a popular tool for quick obfuscation because of its thick lines, but it has an opacity problem that is not visible to the naked eye.
Darken text with the markup tools
To test, use the highlighter in markup to hide text in a photo or screenshot. If you already have some with obfuscation, skip to the next section to see how to find out what’s hidden.
Take a screenshot and tap the thumbnail or open an image or document in an app such as Photos, Files, or Email and find the markup tools. Then tap the highlighter tool, which looks like a thick marker. Tap the highlighter again to adjust the thickness and opacity (make sure the slider is all the way to the right). Next, tap the color picker and choose black. This is the most common color used for concealment.
Use your finger to draw back and forth over the information you want to hide a few times until you can no longer see what is there. You may need to apply some layers to adequately hide the text. When you’re done, save the picture or document as you normally would.
Removing highlighter obscuration from images
That’s the fun part. Find a picture with darkened text, open it in the Photos app and tap “Edit” in the upper right corner to open the picture editor. You will use the tools below to remove the highlighter. Depending on how many black lines were used to hide the text, you should be able to reveal the hidden information with two to six adjustments. Try these out and see what happens:
- brilliance: 100%
- shadow: 100%
- brightness: 100%
If you still can’t see what’s there well, add one or all of the:
- Exposure: 100%
- Highlights: 100%
- contrast: -100%
If necessary, zoom in on the highlighted area to see it better. While you can’t tell everything under the black highlighter, you should see enough. If it’s a phone number, email address, password, or address, there’s a good chance you can tell most of it – if not all of it.
Several other variables can make this process easier or more difficult. If the black highlighter isn’t very thick, you may be able to remove it with just two or three different adjustment tools instead of all six listed above.
The color of the text and background could also complicate the process. If you’re working with black or dark text with a light background, it’s easier to remove the highlighter. However, if the text is a light color, such as yellow, and the background is also light, it can be difficult to see the ad under the black highlighter.
Try it on different background and highlighter colors
Depending on the color of the highlighter, you may need to use different photo editing tools or adjust the same tools up or down. For example, try using the brightness (100) for a red highlighter. If that doesn’t work, try highlights (100) as well. Still a no? Then try some of the other adjustment tools.
For white highlighter, try Sharpness (100), Brightness (-100), Contrast (-100), and Brilliance (100). Below you can see different highlighter colors and how the photo editing tools affect them.
If you’re in dark mode, it doesn’t make much of a difference. If you follow the same steps as before, the black and white highlighter will go away with the correct tools (see below).
Make it harder for people to divulge your private information
To hide sensitive data, you don’t have to leave markup tools in the dust. It is still possible that what you are doing will go away and never come back. And when all else fails, there are third-party solutions.
Tip 1: add more highlighter layers
The highlighter that gives you the best look can still be used to hide content. You just need to use more layers. Instead of just swiping over what you want to hide, lift your finger off the screen before each new swipe. This adds heavier layers of highlighters, making it much more difficult to reveal with simple customization changes.
Tip 2: use highlighters on certain settings pages
Believe it or not, when you take a screenshot of certain information on your iPhone, iOS helps obscure that data when you use markup tools. It seems to work better with obfuscation from an app like Photos, not the screenshot editor. So be careful.
For example the page “Info” Settings -> General. If you swipe over your serial number or IMEI once or twice, iOS will think you’re highlighting it. However, swipe three or four times and iOS will believe you are trying to hide it and will help you by making it impossible to see. Sometimes it only takes two swipes.
Under “Passwords” (iOS 14) or “Passwords and Accounts” (iOS 13) in the settings, a screenshot will automatically remove the password from the page – a nice security feature. You can also hide the username with three or four swipes.
Tip 3: Use the Pen Tool instead
The pencil tool in markup, the icon on the far left, is a fixed “marker”. With 100% opacity, a single layer of pen cover of any color is enough to protect what’s beneath it from prying eyes and image editing tools.
A pencil tool is also an option, but it acts more like a highlighter because you need multiple layers to effectively obscure something. If the layers are thin, someone may be able to reveal the information later. It’s best to stick to the pen when you need 100% security.
Tip 4: Or even the forming tool
You can also use another markup tool to hide information. Instead of using the drawing tools, tap the plus sign (+) in the lower right and choose one of the available shapes. Position it over the text you want to hide, then tap the icon in the lower left for more options.
For the arrow tool, you can create a thick line instead. For the comment field, the square and the circle, you can fill it in so that everything is one color. Then you can choose a color if the current one doesn’t suit your needs. Regardless of what you do later in the image editing tools, you won’t be able to tell what’s under it.
Tip 5: use a third-party app to hide personal information
Better still, you could use professional software to properly disguise private information and faces. Image Scrubber from developer Everest Pipkin allows you to hide information using a high-performance marker, hide faces with an excellent blur tool, and even remove location metadata from the photo so it can’t be traced back to when it was taken. There are other apps out there, but this web tool is our favorite right now.
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