How to Enlarge Images With the Computer

by Julia Lai

Enlarging images requires diligence and some experimentation when done with a computer, depending on what type of graphics software has been installed, the type of industrial scanning hardware, and the type of image that needs to be enlarged. Photographs, including slides, Polaroids, glossy and matte finish images, as well as artwork sketched by hand or produced on a different design machine, can all be enlarged on a computer. While there is no one formula for enlarging all images, certain guidelines apply.

Classify the image according to type. If it is a photograph, identify whether it is glossy or matte. If it is artwork or a sketch, determine whether it was produced in ink, pencil or crayon. If it is a slide, note whether it is color or grayscale.

Choose the appropriate setting on an industrial scanner. On the scanner's menu, each major type of image, such as a photograph or line drawing, will have subheadings that allow you to specify the "screen" that blankets the image. Newsprint, for example, has a special printing pattern that can often be interpreted incorrectly if the scanner is set on "glossy photograph" mode.

Choose a resolution according to how much you intend to enlarge the image. For photographs, slides and artwork, a resolution of 300 dots per inch allows you to enlarge the image two to three times its starting size without it appearing grainy. If you wish to enlarge the image to 10 or more times its original size, choose a much higher resolution, between 600 and 1200 dpi.

Open the image in computer editing software such as Photoshop. From the "Image" menu select "Image Size." Enter the desired larger size in pixels for the new photograph. Check to see how the image appears. If the image appears grainy or washed out, experiment with the visual effects in the "Filter" menu. If these effects do not improve the quality of the photograph, re-scan the image at a higher resolution.

If you do not have access to an industrial scanner, the "scan" option on a photo printer will work. Place the image on the scanner, and enter the desired enlarged size on the printer's menu. The photo printer will scan, resize, and print the image without having to interface with a computer. Or you can import the image from the scanner to your computer, then use an image-editing program to adjust it before enlarging it.


  • check No two images or pieces of equipment are exactly alike. Enlarging an image will require individual attention and some degree of experimentation until you learn how to best manipulate the scanner and the computer software to produce the desired visual effect.

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About the Author

Julia Lai is a frequent contributor to Los Angeles-based arts and literature publications. She graduated from University of California, Los Angeles with a bachelor's degree in history and has been writing professionally since 2008.

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Photo Credits

  • photo_camera control panel of ultrasound scanner image by starush from