Removing Halftone from Scanned Newspaper Photos
My dad recently sent me a scanned photo from an old newspaper that he is using in a historical video he is working on. One of the main issues you face when working with projects of this nature is quality images. Sometimes, you have actual photos, which usually contain a workable amount of visual data to work with. Sometimes you’re on the other end of the spectrum with photocopies of old newspapers.
For this tutorial we’re looking at a pretty typical source image, a scan of a newspaper photo, and how to remove the halftone dot pattern caused by printing.
This image is of Frank Matty – for whom the hamlet of Mattydale, NY, north of Syracuse, is named. One of the only images available was from an old newspaper. Because we generally view newspapers from a comfortable distance, our minds ignore the dots that make up the photo so we can see the overall image without the distracting halftone.
However, when you scan in the image the halftone is much more noticeable – even more so when you use it in video.
Here are a couple of pretty easy steps you can take to eliminate much of the problem.
First of all, you need to know how you are going to use the final image (“begin with the end in mind”). In this case, we’re going to be using it in a video, so the end resolution will be either 72dpi for a static image or 150dpi, or so, to allow for zooms and pans, etc. For these samples, I am using a resolution of 72dpi.
- The first thing you want to do is scan the newspaper in at a very high resolution. Here it was scanned at 600dpi. Sometimes you will want to scan the image at an angle to help avoid as much of a moire pattern as possible.
- In Photoshop, I duplicated the layer and made it a Smart Object – not necessary to do both, perhaps, but I am always over-careful when working on a retouching job – so I could apply Smart Filters to it.
- I added a Gaussian Blur of 3.7 pixels to essentially merge the dots and create smoother gradients. This amount may vary depending on the size of the dots and the resolution at which you scanned.
- I then applied the Unsharp Mask filter with settings:
- Amount: 120%
- Radius: 5px
- Threshold: 1 level
Applying too much sharpening will introduce halos around the edges which will take away from the impact of the image and will look very unprofessional in this usage.
- Resample the image to your end resolution. The resampling will help remove some of the apparent blurriness of the image as well.
- At the end, I just added a simple Curves Adjustment Layer to add some contrast.
Have you run into any issues when working with halftones? Got any tips that we might find useful here? Please share them in the comments so we can all get better results next time!