Understanding digital image files is the key to producing high-quality photos.
In today's electronic world,
commercial real estate professionals are exposed to digital photography
daily, and many of us frequently use digital images in our businesses.
Understanding digital photo production is the first step to creating
visually appealing marketing materials and Web sites.
Digital image production involves capturing the original image vi
scanner or camera, storing images in picture file formats, and
outputting images either for Internet or print use. To produce images
successfully, you must use the correct resolution and file format for
the photo's ultimate use.
guidelines can help you create professional-looking digital images,
whether you place them on your Web site or print them on photo-quality
Deciphering the Lingo
digital image is a file comprising hundreds and even thousands of
pixels. A pixel is the smallest picture element of a digital image, and
image resolution is the number of pixels per inch, or PPI. Larger PPI
numbers indicate more detail, which correlates to better image quality.
Simply put, to have crisp, clear images, set your camera or scanner to
the highest-possible resolution because you always can reduce a digital
image's size to match the intended use, but you cannot increase its
resolution without losing clarity.
digital cameras automatically save images in the joint photographic
experts group, or JPEG, file format. Widely used for images and
illustrations with complex shading and coloration, JPEG is the optimal
format for the Internet because every Web browser recognizes and
JPEG file format compresses images after they are taken, which allows
faster downloads and saves storage space. When opened, a JPEG file
returns to the image's original dimensions. However, each time a JPEG
image is opened and closed it loses varying amounts of data, thus
reducing image quality over time.
the other hand, when tagged image file format, or TIFF, images are
opened and closed, they are mathematically and visually identical to
the originals. TIFF files commonly are used in print publishing,
Internet-based faxing services, 3-D applications, and medical-imaging
professional photographers prefer the raw file format because it stores
only the raw image data, allowing later color processing, tonal and
exposure correction, and image sharpening without compression's
constraints. Raw files are the digital equivalent of undeveloped film
negatives. However, raw files are not universally supported on the
Internet, and each camera manufacturer's raw format is different.
Digital Image Production
must consider the resolution when capturing and outputting digital
image files. The two resolution aspects to consider are spatial and
resolution refers to the number of pixels in an image file. You would
have to magnify a high-resolution image to see its pixels; however, it
may be possible to see individual pixels in low-resolution images,
which appear jagged or grainy.
resolution refers to the number of brightness levels that can be
recorded in a pixel; a higher brightness resolution means a greater
number of levels. When you print a photo, the brightness information is
used to determine the number, size, and color of the inkjet printers'
dots of ink or the color and amount of laser printers' toner that is
laid down on the paper.
digital images, regardless of format, ultimately are resolution
dependent, and the number of pixels limits an image's quality, as well
as the printed image size. A relationship also exists between the
captured image's resolution and the output device's resolution. For
instance, a computer screen can display far fewer dots per inch, or
DPI, than a photo-quality inkjet or laser printer can print.
how do you know the resolution at which to capture your original image
to achieve quality output results? Let's use a photo-quality inkjet
printer as an example. The table shows two output resolution ranges and
the associated DPI. You do not need the same resolution in your
original digital image as the resolution of your printed photo. The
table assumes that 200 PPI is adequate for good quality and 300 PPI is
required for high quality. Using these figures, the table shows the
total number of pixels required for four standard-size printed photos.
camera's specifications come into play here. With a 2-megapixel camera,
a photo taken at maximum resolution is about 2 million pixels, or about
1,200 pixels by 1,600 pixels, which enables you to print a good-quality
photo at 5 inches by 7 inches or a high-quality photo at 4 inches by 5
inches maximum. If you intend to print good-quality 8-by-10 photos, you
would need a 3-megapixel camera with about 1,536 pixels by 2,048
pixels. A 5-megapixel camera at 1,944 pixels by 2,592 pixels can
produce high-quality 8-by-10 photos.
is nearly impossible to preserve an image's quality when increasing it
beyond a pixel-imposed size limitation. A good rule of thumb is to
always capture photos at your camera or scanner's highest available
you are looking for a new digital camera, evaluate models that will
achieve high-quality images for your various marketing needs. Many new
point-and-shoot digital cameras have 5 megapixels; professional digital
SLR models offer as many as 18 megapixels. However, most commercial
real estate professionals can produce excellent photo-based materials
with a 3-megapixel digital camera.
For more information on digital photos, visit Hewlett-Packard's Digital Photography Center at or Kodak's Digital Learning Center at .