The magazine of the Melbourne PC User Group
Pixels to Prints
 Calvin Jones

Calvin Jones explores the art of producing high-quality prints from your digital images...

One of the great things about owning a digital camera is the affect it has on your photography. Free of the costly shackles of film and processing you can experiment with technique and composition in ways that you wouldn't even consider with a film camera.

As a photographer though you will still want to print some of your best shots. Whether it's to share with family and friends, populate the family photo-album or simply to hang on the wall, sooner or later you will want real-world prints from your digital image files. The good news is that getting high-quality prints from your digital camera is much easier than you might think.

The Simple Approach

Digital Mini Labs

The easiest way to get prints from your digital camera is to simply snap away, then take your camera or memory card to a digital mini-lab. These are cropping up everywhere as older machines are upgraded, with Fuji leading the way (check out http://www.fujicolour.com.au to find a digital-enabled Fuji lab in your area). You drop off your memory card, just as you would a roll of film, and call back later to collect your prints. It really is that simple. Results can be a bit unpredictable - due mainly to the cropping issue mentioned later in this article, but you can get very good prints with a minimum of fuss.

Inkjet Photo-Printers
A number of inkjet photo-printers on the market today have slots for digital camera memory cards (See Figure 1). You simply slot in your card and print off an index print. Some of the newer models even let you view your photos on a small LCD screen. Once you've picked out your photographs and print size you just load the printer with photo paper, hit the print button and out come your prints. Simple!

Preparing Your Image Files

One of the beauties of digital photography is the level of control it affords the photographer throughout the imaging process. If you want to realise your own creative vision, rather than having your photographs interpreted by a mini-lab operator and an automated machine, then you will need to take a more hands-on approach. The example below shows you how to prepare a standard 8x6 print using Adobe Photoshop, but the same process can be used to prepare any size of print and the same principles apply to most common image processing applications.


Figure 1. Some printers enable you to print directly
from your camera's memory card without a PC.


Figure 2. It makes sense to use a working 
folder and modify copies of your files, not originals.

 Select Your Images

The first thing you need to do is choose the images you want to print. If these images are still on your camera's memory card first copy them to your computer. As a rule of thumb never work on original files straight from the camera: these are the digital equivalent of your negatives. Instead, create a working folder on your hard drive, and copy the images you want to print into this working folder.

The Digital Darkroom

So, now you have copies of your images in your working folder, what next?

It is time to get to work with your image processing software. Basic image processing can work wonders to improve your digital photographs. For an excellent overview of image processing techniques using both Photoshop and Paintshop Pro take a look at the tutorial on photographer Larry Bolch's Web site http://www.larry-bolch.com/basicprocessing.

Another tip at this stage is to resave your processed images in a lossless image format (like TIFF). Saving/resaving in JPEG format introduces image degradation due to the lossy nature of JPEG compression.

Resizing Your Image

Once your images have been modified and resaved you will need to resize them to your chosen print size at a resolution of 300 ppi - commonly agreed to be the optimum resolution for photo-quality prints.


Figure 3. Photoshop's Image Size dialogue lets you modify your file's dimensions and
resolution.

 To do this in Photoshop:
  • Open an image file and go to the Image menu
  • Choose Image Size and the Image Size dialogue will appear...
  • Make sure that the Constrain Proportions and Resample Image check boxes are selected and that the Resample dropdown is showing Bicubic
  • Now change the value in the resolution box to 300 ppi and the value in the width field to the desired width for your print - in our case 8 inches (note that the dropdown lists next to each dimension box let you select the units used to specify the dimension).
  • Because Constrain Proportions is checked the height value is automatically calculated based on the aspect ratio of the image file.
  • Click on OK and Photoshop will resample the file to the required size and resolution
  • Resave your image

Repeat for all images.

How Big Can I Go?

The size of print you can achieve while maintaining quality depends on the size and resolution of the original image, and is a subjective call based on your own requirements. However, any image from a camera above 3 Mp should give you a very good 10x8 print.

Figure 4 is a chart of the calculated maximum print sizes at 300 ppi, 200 ppi and 150 ppi for common camera resolutions with no software interpolation applied - but in practice you can often get great results at much larger sizes. The only real way to tell how big you can go is to experiment with some test prints.


Figure 4. This table gives the calculated maximum print size without
interpolation for popular digital camera resolutions. In practice
these sizes can often be exceeded with surprisingly good results.

Printing at Home

You can get stunning prints at home with the latest generation of photo quality inkjet printers. However, to get the best out of these printers it's important to follow a few simple guidelines.

Inks and Paper

Inks and paper are of paramount importance in getting the most out of your photo quality inkjet. Generally you will get better initial results using ink cartridges and photo paper produced by your printer manufacturer. Once you are comfortable with your printer and your printing workflow you can experiment with third party products to find a combination that works well for you. To start with though, try the heaviest coated photo paper (either glossy or matt) produced by your printer manufacturer.

Print Life

One thing to bear in mind when printing using an inkjet printer is that the longevity of inkjet prints varies widely depending on the printer, paper and ink combination used. Tests show life spans of anything from two years to over a hundred years before noticeable fading occurs (see http://www.wilhelm-research.com for more details). Of course, another plus for digital photography is that the original file won't degrade at all, so as long as the archived file is safe a faded print can easily be replaced with a pristine new one.

Printer Settings

Your printer driver can make or break your prints. It is vital that your driver is set to provide the best possible output on your photo quality paper. It is also a good idea to keep your printer driver up-to-date by periodically checking the manufacturer's Web site and downloading any updates.

Printing The Image

Back to our example:
  • With the 8x6 image open in Photoshop go to File, Page Setup. The Page Setup dialogue will appear (see Figure 5)
  • Make sure the paper size matches the paper you are using and the paper orientation matches the orientation of the image
  • In the Printer section at the top of the dialogue make sure your photo quality inkjet printer is showing in the drop-down list and click on Properties
    Your printer driver dialogue should appear. Exactly how this looks will depend on the make and model of your printer and the version of the driver you are using. The two printer settings we are most interested in are the paper type and the print quality.
  • Set the paper type in the driver to match the paper you are printing on (with printer manufacturer's paper you should find an exact match, with third party papers follow the guidelines given by the paper manufacturer)
  • Set the print quality to the highest possible setting


Figure 5. Photoshop’s Page Setup dialogue.

If there is an option in your driver to preview the printed page before sending it to the printer select it. If you notice something wrong with the preview (eg. incorrect orientation) you can cancel the print and save expensive ink and paper.

Go to File, Print and send your image to the printer and watch as your masterpiece unfolds. After allowing a little drying time trim the excess paper and voila... a home processed print from your digital camera!

Printing At A Digital Mini-Lab

Another route for getting your pictures printed is to take your prepared files along to a digital mini-lab. Check with your local labs to see if they offer a digital service.

Print Size And Cropping Issues

Digital mini-labs produce prints in a predefined range of sizes, such as 6x4, 7x5, 8x6, 10x8 and larger. Some of these print sizes do not match the typical aspect ratio of a digital camera file, and will result in some of the image being cropped when it is automatically resized to fit the paper - unless we compensate by modifying the file accordingly.

Consider a digital image file resized to 10x7.5 using the method above. The nearest available print size is 10x8 so to avoid arbitrary cropping we need to provide a file with 10x8 dimensions. 


Figure 6. Setting the right paper type in your printer driver is imperative to get the best print quality.

The easiest way to do this is to change the canvas size. In Photoshop you simply go to Image, Canvas Size and change the height to 8 inches. Photoshop will add a border above and below the image making the file exactly 10x8.

File Format and Media

You should check what file formats and media types a particular mini-lab can read. Bear in mind that image files can take up a lot of space (over 20 MB for an uncompressed 10x8 saved at 300 ppi).
 
Once you have copied your chosen images to your digital media you can drop them off at the lab for printing. Make sure you let the operator know at this stage that you don't want any additional adjustments made to your images.

The end result is that your prints will be produced on photographic paper using exactly the same process as prints from 35 mm film. The only step that is skipped is the scanning of a 35 mm negative.

The Online Option

There are a growing number of labs that allow you to order over the Internet. You upload your selected images and they send your prints through the post. These services enable you to submit orders from the comfort of your own home, and are useful if you don't have a digital mini-lab locally. Bear in mind though large file-sizes mean substantial uploads, which may only be practical with a broadband connection to the Internet.

Summary

So going digital doesn't mean the end of those 6x4 snapshots or those glorious enlargements that grace the living room wall. In fact, with digital you have more options for printing your images than ever before. You also have the flexibility and freedom to experiment with your photography, safe in the knowledge that if you capture that magic shot a superb print is only a few simple steps away.

About the Author
Calvin Jones, calvin@nivlac.net took the plunge in 2002, left the IT industry after 10 long years to pursue his passion for writing and photography. He picked up his first camera at the age of ten, got his hands on his first SLR by the time he was twelve and was immediately hooked. An avid photographer ever since, he has embraced digital photography and now rarely ever shoots film. To view samples of Calvin's work visit his Web site on http://www.nivlac.net.

Reprinted from the March 2003 issue of PC Update, the magazine of Melbourne PC User Group, Australia

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