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Digital photography printing has opened new avenues for amateur and professional photographers alike. For most photographers, the backup of digital photography printing offers unprecedented freedom to get the best shots. No more worrying about wasting that precious piece of film running out, in addition to not knowing for sure that anything worthwhile is on it!

However, when it comes to getting the printing done, there are a few things one should keep in mind to prevent wasting too much of quality photo paper, and the costly printing ink. In this article, we’ll review a few basic terms related to digital photography and offer a few tips on getting the best prints.

Resolution

Resolution refers to the ‘image-sharpness’ of a document, and is usually measured in dots (or pixels) per inch (DPI). It also refers to the image-sharpness that printers and monitors are capable of reproducing. Depending on your particular needs, documents can be scanned at various resolutions. The higher the resolution of a document, greater the image-sharpness, and larger the file size will be.

With digital photography printing in mind, the first thing you need to ensure is that you download the pictures at their full resolution. If in the end, you have 72dpi (dots per inch) pictures, your print quality will be useless. A 72dpi resolution is good for viewing on your computer screen, but an image with 200 to 300dpi will give a good quality 8×10 inch print.

Pixel

Pixel is short for ‘Picture Element.’ It is the smallest part of a digital image, and each image is comprised of thousands or millions of pixels. This basic unit, from which a video or computer picture is made, is essentially a dot with a given colour and brightness value. The more pixels an image has, the higher the resolution of that image will be. One Megapixel is equal to one million pixels.

JPEG

Joint Photographic Experts Group (JPEG) is a standards committee that designed this image compression format. The compression format they designed is known as a ‘lossy’ compression, as it deletes information from an image that it considers unnecessary. JPEG files can range from small amounts of lossless compression to large amounts of lossy compression. This is a common standard on the World Wide Web, but the data loss generated in its compression makes it undesirable for printing purposes.

When dealing with digital photography printing, you will mostly work with the JPEG file format. Remember that every time you open and save a JPEG file, you lose some of the image information. Therefore, it is advisable to do all the changes in one sitting, and then save them only once.

Resolution Guide to Quality Prints
The higher number of megapixels a camera has, the more detail an image will retain when enlarged and/or printed.

1 to 2 Megapixels

Cameras with this resolution range are sufficient for sending photos electronically via email, but are not ideal for printing photos. Most camera phones, PC camcorders, and PC cameras have a resolution in the 1 to 2 megapixel range.

3 to 4 Megapixels

Cameras with this resolution range are good for printing and retouching the standard 4×6 inch images.

5 to 6 Megapixels

Cameras with this resolution range produce professional results when enlarging photos up to an 8×10 inch format.

7+ Megapixels

Cameras with a resolution range of at least 7 megapixels promise superior quality and detail when printing or enlarging photos beyond the 11×14 inch format.

By simply looking at the file size, you will quickly learn to be an expert judge on quality. A picture of 100kb (kilobytes) or less is most probably too low-resolution for good quality digital printing. Once you get to a minimum size of 400kb, you are working with a more useful resolution for an 8×10 inch print.

Printing Paper

If you’re proud of your photographic effort, or if you want those family shots to be available for the next generation, you will definitely want your prints to be done on decent paper. Needless to say, in the end, your prints will be only as good as the paper you use.

There are many new coated papers available on the market specifically for this purpose, and you should consider what is recommended for the printer you are using.

Archival paper, popular in the world of inkjet printing, is the longest-lasting paper and it is acid-free. These printing papers don’t come cheap, so plan carefully. Print only after final cropping, or on completion of other changes, such as after the addition of a border with your imaging software.

Regular colour inkjet and laser printers are good for text and charts, but not always best for digital photography printing. PictBridge-enabled printers allow you to print your digital photographs directly from the camera. Portable printers, such as the HP Photosmart 320 series, allow you to take a picture and print 4×6 inch sized pictures anywhere on the move.

Incidentally, for smaller 4×6 inch prints, dye-sublimation printers give outstanding quality prints, and they are generally waterproof. However, the materials for such printing do not come cheap!
If you cannot get satisfactory results with your own digital photography printing, especially if you’re printing larger than 8×10 inch sized images, you could try one of the brick-and-mortar, or even online photo labs that make use of dedicated photo printers with excellent results.

Photo labs can easily handle digital files directly from your memory card. Take your digital camera, a homemade CD, or your camera’s memory card along for professional quality digital photography printing.

John Sollars is the managing director of Solar Electronics, which are both ink and pc peripheral suppliers based in Shropshire, UK. To access a comprehensive online shop of original and re-manufactured hp and canon inks please visit http://www.mega-office.co.uk

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Your time is valuable. It’s annoying when you receive an image which is too large, too small, or impossible to open.

And your customers, suppliers, or friends will hate you if you do it to them.

In this short article, you’ll learn how to send the right size image, in the right format. It’s surprisingly pretty simple, once you know how.

Image formats and sizes seem complicated at first, which is why people send images that are the wrong size or format. But once you understand a couple of basic principles, you’ll be able to easily size any image appropriately and send it by e-mail or upload it to a web site.

Begin with the end in mind

Take Stephen Covey’s advice - start by being clear about your goal. What is the person to whom you’re sending the image going to do with it? Is it just for them to look at on their computer, or will they need to print it? It makes a big difference (the reason is simple, and you’ll find out what it is in a minute). If the image is to be printed, how big?

Pixels and DPI

The answer to the sizing problem has to do with pixels. Unless you’ve been living in a bunker for the last five years, you’ve probably heard of them. You may even have an idea what a pixel is: the smallest element of a digital image - a single square (rectangle, actually) of a single colour.

The resolution of an image is expressed in PPI, or Pixels Per Inch. This is often confused with DPI (Dots Per Inch). Strictly speaking, DPI actually relates only to printers, but in practice, the terms are often used interchangeably.

Resolution essentially determines how large the image can be reproduced. This also depends on the output device (computer screen or printer). It’s important to understand the difference between size and resolution. The best way to do this is with an example…

Let’s say we have an image which is 300 pixels wide by 150 pixels high. This is the size or pixel dimensions of the image. Simple enough. But here’s the tricky bit (so pay attention):

The typical computer screen size, in pixels, is 1024×768 pixels. The resolution is usually 75 PPI (which means every square inch of screen ‘real estate’ is 75 pixels wide by 75 pixels high).

Therefore if we look at our 300 x 150 pixel image, it will be four inches (10 cm) wide and two inches (5 cm) high. Fine so far. But what if we now want to print that image?

Different printing devices can print at different resolutions. But generally, for an image to print well, it needs to have a resolution of at least 200 PPI, or preferably 300. Any less than this, and it will start to look chunky, fuzzy, or pixellated. Or all three!

You may have heard of printers which can print at 1200 DPI or more, but this is separate from the size of the image itself - there’s really no need to send a 1200 PPI image to your printer.

So you can see that our 300 x 150 pixel image will only print at a size of about 1 inch (2.5 cm) wide by half an inch high. Big difference!

By now you’re probably thinking, “OK, enough geeky explanations, how big should I size my image?!”

Here are some guidelines, then:

• On-screen viewing: height 500 to 700 pixels, width 700 to 900 pixels
• Print - 200 to 300 PPI. So for a 4×6″ (10×15 cm) print, the pixel dimensions should be 800 x 1200 at the smallest, or 1200 x 1800 at the largest. Obviously for a larger print, you need to increase the pixel dimensions accordingly.

The good news

Most imaging programs do all the calculations for you in the “resize” function. Here’s how to resize images in the most popular image editing applications:

In Photoshop (including Photoshop Elements), go to Image –> Resize –> Image Size, where you can either specify the new size in pixels; or in centimetres or inches. Don’t forget to set a suitable resolution for your end use (75 PPI for on-screen viewing, 200-300 PPI for print).

The procedure for PaintShop Pro is very similar: Go to Image –> Resize, where you can resize either as a percentage of the original size, specify the new pixel dimensions, or specify the absolute size in cm or inches and PPI.

If you don’t have either of these programs, you can even resize in Windows Paint. Choose Image –> Stretch, and then enter the new size as a percentage of the original size.

It’s also worth checking out Irfanview, a free image viewer which has been around for years. It supports every imaginable image format (and then some), and includes batch processing (allowing you to resize or otherwise adjust multiple images in one operation) as well as slide shows and a bunch of other features.

In Windows XP (and possibly some other versions) you can also check the size of your image without opening it, by hovering the mouse pointer over the file within Windows Explorer. A box soon pops up with all of the details.

Formats

OK, the last thing to think about is image format. Not only does this substantially affect the size of the file (in bytes), but also whether other people can open it!

You may have noticed that the most common format is JPEG (which stands for Joint Picture Experts Group, if you must know), often abbreviated to its three-letter Windows file extension, jpg.

Most likely your images are already in JPEG format if they have come from a digital camera, although some digital cameras can capture images in TIFF or RAW formats (which are beyond the scope of this article).

There are a couple of good reasons for the popularity of JPEG. The main one is size. A postcard-size, 300 DPI image takes up about 6 MB in it’s ‘native’ format. That’s one big e-mail! The same image saved as a JPEG takes up around one-tenth of that when saved as a JPEG at a decent quality setting.

(The other reason JPEG is a popular format is because it’s extremely widely supported - as well as digital cameras, every image editing or viewing application can handle it - which in turn ensures its popularity!)

So by ‘compressing’ the image, JPEGs take up a fraction of the space of most other formats. There must be a catch, right? Well, yes and no. Let’s explore a little deeper.

JPEG uses an algorithm (mathematical formula) to compress the image. And it does this essentially by “summarizing” parts of the image with less detail in them. In order to do this, and achieve the incredible ratio of compression which it does, it actually “throws away” some of the data (technically, it’s known as lossy compression - as opposed to lossless compression. An example of a lossless compression algorithm is zip).

Well, “throwing away” bits of your picture doesn’t sound too good, does it. Actually, it’s not as bad as it sounds. When you save an image as a jpeg, you’re presented with a choice of quality setting (exactly how this is presented varies from program to program). As you would expect, the higher the quality, the less compression is achieved, and vice versa. However, even at fairly high quality settings, the amount of compression is still substantial, yet the degradation (in the form of compression artifacts) is barely perceptible.

By the way, if you do need to send an image file which is larger than about 1 or 2 MB, a file transfer service like yousendit.com or megaupload.com is a much more elegant way to do it than e-mail. It saves clogging up both your own e-mail as well as the recipient’s. All you do is browse to the file on your computer and enter the recipient’s e-mail address, and the file transfer service does the rest.

Hopefully you’re now ready to give it a try! In summary:

1. Know your goal

2. Resize the image to the appropriate pixel dimensions, if required

3. Save in JPEG format with a reasonably high quality setting

Now go ahead and e-mail some pictures around the place!

Steven Pam is the founder of SmartShots Commercial Photography, based in Melbourne, Australia.
He specializes in photographing people, cars, and anything to do with aircraft.

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