Digital Photo Image Enlargement Picture definition or the image resolution depends on many factors. Often you might have to enlarge the image after cropping for printing. Sharp details become fuzzy and pixelated when you try to enlarge the original image beyond a point. The ability to resolve sharp details even for moderate enlargement depends on the software algorithm and the interpolation technique used.
Digital photos store details in pixels. It is not advisable to merely enlarge or magnify the image without interpolation. The amount of digital information about an image is based on the settings at the time of the snap and this information is fixed.
Most people who try and go in for digital photo enlargement notice the effect of 'pixelation' - the loss of quality of the image. Typically if you try and enlarge a 1-megapixel image into an 8 X 10" format, you are likely to get a blurred and jagged image - an example of pixelation. Every digital image has its own enlargement limits. Standard digital images of 480x640 pixel should not be enlarged more than 8 x10". Megapixel digital photos can be enlarged slightly more. 1 megapixel digital photos are good for sending across by e-mail while 4 megapixel digital images can be enlarged upto 11 X 14". 6 megapixel images can be enlarged as much as 16 x 20".
Enlargement of Digital Images
Other things being equal, the rule of thumb is always start with the original uncompressed image for further manipulation. The higher the resolution of the image, the better will be the final product. Every step and every tool forms a link in a long chain. If there is a weak link anywhere along the line, your final product will not be worth the time you spent on it.
Standard image editing software like PhotoShop are capable of decent level of enlargement with out excessive pixelation. The image on the right side (top) is a 450 x 511 Pixels sized image while the enlarged image appears beneath it. These images depict the frontal view of the Bom Jesus Basilica in Goa,India.
More specialized software are available which can enlarge any image to a much greater enlargement level than possible with standard software. You will find a few links, as usual in our directory section.
Interpolation is a process whereby digital photos are enlarged by increasing the number of pixels in that image. Photo interpolation tools stretch the digital image and generate pixels to fill in the space. Interpolation is done with either of the following methods:
- Nearest neighbor interpolation
- This method of interpolation creates new pixels similar to the ones close by. The duplicated pixels tend to create a pixelated image with jagged edges.
- Bilinear interpolation
- With Bilinear interpolation, the 4 surrounding pixels are filtered and smoothened out to create a sharper image. Color is added from the surrounding pixels.
- Bicubic interpolation
- Bicubic interpolation analyses 16 surrounding pixels and uses that information for enlargements. This method gives good results. This allows you to get a clearer enlarged image with smoother lines than from the original photo.
You can make enlarged prints of digital photos and film-scanned images. Even small sections of digital photos can be interpolated and enlarged.