Top Six Photo Enlargement Tips

1. Note the original size of the image before doing anything;
2. Instruct photo enlargement software to resize the image to a specific resolution rather than a specific size or percentage enlargement;
3. Choose a simple interpolation algorithm or enlargement engine similar to Photoshop for downsizing the image;
4. Resize the image back its original dimensions that you wrote down in a second operation.

Digital images such as graphics on a web page or photos from a digital camera are all made up of pixels – “picture elements” – tiny units of picture information. Every image on your computer is represented by this colored grid of pixels.

Computers use pixels to measure instead of inches. Printers use inches to measure instead of pixels. Therefore an image on the screen can appear very different than the same image when printed.

Pixels transform into inches through what is called “resolution,” – the number of pixels per square inch on a computer. So DPI or dots-per-inch is an expression of the resolution of an image. Resolution allows you to transform pixels into inches and back again.

Some photography shops have huge machines that are hardware photo enlargers. They look like giant microscopes, some taller than an average person. Try to think image resolution in terms of what you would need to enlarge a photo with one of these expensive hardware photo enlargers. You would need a beginning photo print that had a sufficient record of the detail in the image - that had sufficient image resolution. If you took an image below 200 DPI to a hardware photo enlarger you would not get satisfactory results even on the highest machines. Internet images or otherwise low resolution photos don’t have enough tiny dots that make up the picture. Before enlargement, this is the most important consideration. Remember, no hardware photo enlarger or any photo software can enlarge what simply is not there.

The JPEG image format is a “lossy” image format. This means saving in the JPEG (JPG) format always attempts to take image information out of the image. Image quality and resolution are never improved using JPEG. Even saving a JPEG image using the highest quality setting (least compression) drops information from the photo, though the lost information will be in the brightest or least noticeable areas. Opening a JPEG and resaving a JPEG will accumulate loss in the photo.

JPEG compression works by examining pixel brightness, then assigning that pixel a “score” on a scale of -1024 to +1024. JPEG compression (“optimization”) works according to brightness - not by color. Compression is greater in brighter less visible areas of the image and less in darker areas. JPEG compression uses a complicated mathematical formula that operates on 8x8 blocks of pixels to score brightness. Magnifying jpeg images clearly reveals these blocks.

Why is this important? Many people think JPEG images are great for printing (and enlarging) because they often look very good on web pages or in photo directories. Remember though that JPEG was developed for use on the web, where file size considerations are very important. Before the web, back in the days when glossy magazine type printing was the primary media, graphic artists had little use for GIF or JPEG images all images were printed. So, when choosing which format to save your images to, consider what you are going to use the image for - if it is for printing or photo enlargement, GIF or JPEG formats should be avoided, and TIFF or possibly PCX should be considered as better (less lossy) alternatives.

Increase memory in your computer.
Computer memory is relatively inexpensive these days and will make your computer run faster anyway. This is very important for photo enlargement purposes.

Photo enlargement is not like any other computer operation.  It can be totally memory consuming as the computer must hold:

• the image itself plus ...
• the photo enlargement program, and ...
• the completed photo enlargement ...

Sharpen image, even if not enlarging.
Every digital image can be improved by employing the software version of sharpening procedures photographers have been using for decades. A procedure called “unsharp mask,” and most photo editing software has this ability. This procedure will make any photo sharper.

The simplest explanation of the unsharp mask sharpening procedure is to copy the image you want to sharpen, make the copy slightly more blurry then blend the two back together. This produces what looks like the faint ghost of the original image and is then used as a filter or “mask” over the original image to make it sharper. Click here for the simplest definition of how to use unsharp mask settings.