Some of the questions we’re often asked are, ‘What DPI are your images?’ and ‘Are your images 300 dpi?’.
All of our images were originally scanned at 300dpi or 600dpi. The quality of the images scanned from books is dependant on the quality of the original image and the print method. Most images in books are made up of a ‘screen’ of tiny dots of colour (the process is known as halftone), usually too small for the human eye to identify unaided. Sometimes, when we scan them at a high resolution, the dots are very visible when zooming in on the image.
Depending on the intended use for the images, it may be desirable to use a graphics program to make the dots less visible. As well as Photoshop, there are some free applications which can help you do this. Some are web based and some are applications to download and install. We looked at a lot of these applications and here are a few of the best which we’ve narrowed it down to…
- GIMP – This image editor is available for macOS, Windows and other operating systems. Once downloaded and installed, load up your image and then select Filters, Enhance and then Noise Reduction. Experiment with the settings to find a good balance between dot removal and blurring. The resulting image can be sharpened to restore any lost clarity.
- Photopea – This web based app is free and very simple to use. Load up your image and then select Filter, Noise and then Reduce Noise. We also had good success using the Median filter under the same Noise menu. Again, experiment with the settings and sharpen the image if necessary.
- Pixlr – This app can be used web based or there is a version you can download and install. They both seem to have the same functionality. Go for the Advanced Editor and click on Open Image to start. You can open your image in the original size or you’ll have the option to resize it to speed things up. Select Filter, Details and Remove Noise. Experiment with the settings and then sharpen up the image if you need to.
