June 10, 2006

Printing Digital Images – Part One

Digital photography has put the process of developing pictures into the hands of the consumer. This also includes printing -- anyone with a decent printer attached to their computer can print out their own photographs.

Digital images are usually transferred to a computer where they can be edited and processed with specialized software. Finally, they can be printed out, but to get the best quality prints possible a few guidelines should be followed.

In the process of transferring images to your computer, some software packages automatically downsize the pictures to make them easier to send by e-mail or post on web sites. For printing, however, downsizing should be avoided. Always make sure you are transferring images to your computer at their full resolution.

Even at full resolution, however, some cameras do not have enough pixels to make decent printed pictures. Photo processing shops print pictures at 300 pixels per inch, and if you want that same kind of quality you must have images that are at least that resolution.

Pixels (picture elements) are the individual dots that make up a digital photograph. Cameras are usually rated in megapixels (millions of pixels) - the total number of pixels a camera can record. A camera which is rated at six megapixels, for example, can capture images which are 3008 pixels high by 2000 pixels wide.

The number of pixels in any digital image is fixed, so increasing the size of a photo means there are fewer pixels per inch. If the image is blown up beyond the standard of 300 pixels per inch clarity and sharpness will be reduced. Photos from cameras rated at two megapixels can be printed as large as 5.8" x 3.8" at 300 pixels per inch. A four megapixel camera can print photos as large as 8.2" x 5.4".

The first step in getting good-quality prints, therefore, is to make sure your images are at the correct resolution – at least 300 pixels per inch.

Editing

One of the advantages of digital photography is the ability to edit images before they are printed out. There is a problem, however, with editing JPEG images -- each time they are resaved they lose a little bit of data. This means that if you make several edits to a JPEG file, and save the file after each edit, the quality of the image will decrease significantly.

In order to avoid this, try to minimize the number of edits to a JPEG image to one or two and save the edited image under a new file name. This will keep the original file intact. Alternatively, store the images in an uncompressed format like TIFF. This allows you to do as many edits as you wish without any loss of quality.

When it comes time to print out your pictures you have two basic choices -- print them yourself or send them to a photo processing shop. Many photo shops have an online service which allows you to upload photos to their server. When they are printed (which can take as little as one-hour) you can pick them up or have them mailed to you. Alternatively, do it the old-fashioned way – take your pictures directly to the shop. Photo processing shops may have computers that you can use for free to edit your pictures before they are printed.

You can also print your pictures at home – that's the subject of the next article.

Posted by DigitalCamera at 12:51 PM | Comments (0)

June 09, 2006

Printing Digital Images – Part Two

Most people who own a computer have a printer that goes along with it, and this printer is most likely capable of printing out digital pictures. Here are a few tips to get the best results when printing your own photographs.

Each major printer manufacturer also makes its own paper and ink. For most printing jobs you can usually use any type of paper and ink, but in order to get the most accurate colour reproduction for photographs it's best to use the same brand of paper and ink as your printer. Each brand of paper is formulated to give optimal results for a particular type of ink. Mixing brands may give you altered colours.

When choosing paper for printing digital photographs, you may be tempted to select special archival paper which is reputed to prevent photographs from fading for 20 years or longer. This paper is quite expensive, so before laying down the bucks consider this -- the zeros and ones that make up a digital image will not fade over time. You can always print the picture again to recapture its original brilliance.

That is not to say, however, the paper is not important. You need to use specialized photographic paper that is designed for inkjet printers. It is available in different finishes from glossy to mat. Store it in a cool place away from direct sunlight. Photographic paper is more expensive than regular printing paper, so it is a good idea to minimize waste. Photo printing software can help you to position photos on a sheet of paper so that the maximum area is being used.

Ink is also quite expensive. To avoid wasting it, make the proper settings on your printer for the type of image you are printing. If you are printing a picture which has a resolution of 300 dpi (dots per inch), for example, there is no need to use the 'high' or 'best' printer setting – 'normal' is sufficient. When the printer is set to 'high' it uses more ink and will not produce noticeably better prints as long as you are printing at or above 300 dpi.

How can you tell if your picture is 300 dpi? This can be calculated by dividing the dimensions of your image (in pixels) by 300. For example, if your image is 3000 pixels wide by 2100 pixels high, the maximum size the printout can be (at 300 dpi) is 10" x 7". You can print pictures larger than this (down to about 200 dpi), but in this case you want to select the 'best' printer setting to achieve a good printout.

Dedicated Printers

An alternative to using your regular inkjet printer for printing photos is to get a dedicated photo printer. These use a different printing technology that produces high-quality pictures. The downside to dedicated printers is that they are usually limited to a maximum print size of 4" x 6". They are, however, quite small in size and easily portable.

Dedicated printers use thermal-dye technology. Dye is transferred from a ribbon to the plastic coating of the paper and the resulting picture is more like a traditional photograph than the ones produced by inkjet printers. They also tend to last longer than inkjet printed pictures because of the way the ink is laid down on the paper. Each colour is printed as a separate layer and there is a finishing overcoat which can protect the image from deterioration.

These printers are easy to use and may include simple picture editing functions. They can print pictures directly from your digital camera or memory card, and battery operated models can be used anywhere.

Posted by DigitalCamera at 12:53 PM | Comments (0)