Imagine That!
(Page 4 of 5)
Do-It Yourself
Options include:
Using a scanner
Scanners are wonderful toys/tools. I have had the opportunity to work with a variety of
scanners ranging from black & white hand scanners to a number of color desktop versions
including (IMHO) the best in the world, the Scitex 342L. I have also been exposed to a
few drum scanners.
In the high-end world of scanners (tens of thousands of dollars),
I prefer flatbed scanners over drum scanners because of the necessity of
production. Flatbed scanners will allow you to crank stuff out quickly with
acceptable quality. They are more than adequate for scans for Web pages.
On the low-end side, there are flatbed and sheetfed scanners. Again, I prefer
flatbeds. Prices for low-end scanners have dropped to as low as a few hundred (US) dollars.
When selecting a scanner, look for at least 24bit color and at least 300x600 optical
resolution. Scanners can interpolate data (run math algorithms to perform best guesses
of where data should go) to 4800x4800, but that is not the same as the maximum
optical resolution. Scanners usualy come with bundled software which may include
the scanning application, image-editing software, and OCR (Optical Character Recognition)
software.
Other scanner considerations are speed, number of passes, size of maximum scanning area,
transparency or slide attachments (if necessary).
Calibration is another issue. Anyone can slap a photo on a scanner and slam it into the machine.
Getting the scanned image to look like the original image (or, more accurately, what your brain perceives as
the original image) is another story. There are several considerations such as:
- White and dark point settings
- Brightness and contrast
- Adjusting curves for quartertones, halftones, and midtones
- Color balance
- ...and these are just the beginning
Calibrating a scanner can be a tricky process. Remember that you are seeing the image that you
scanned through a monitor that must also be calibrated. This simply makes it more complicated.
I would reccommend getting your system calibrated using numbers rather than observation. One way to
achieve this is to scan samples of something where the color is known, like swatches from a
Pantone Prosess Color Imaging Guide. Check the values of the scanned swatches
in an application like PhotoShop
where the values of the image are displayed accurately regardless of how they appear on your
monitor and tweak your scanner settings from there.
I would like to stress that calibrating a new piece of equipment like a scanner is usually not
a simple process and can take several hours or days (or weeks depending on how crazy you want
to get with it), and that after the device is calibrated, it is likely to shift out of calibration
over time (yet people do it every day).
This text is meant simply to provide a starting point and a direction to work in.
Remember that there are millions of Web readers out there and each one has different
settings on different machines. Do the best you can with the tools you have to use.
Using a digital camera
Digital cameras are also becoming popular as price drops. Many digital cameras save data
in the form of JPEG files (lossy compression),
so editing (for color correction or cropping) these files and saving them again in a JPEG format
is going to result in a further loss of data.
As with scanners, the process of getting the image you see in your mind onto your monitor can be
a lengthy bit of tweaking. Considererations include lighting, shadows, brightness, and contrast.
Practice with various objects and become familiar with your equipment.
Taking pictures of products
for a digital database is much different than capturing a football player being tackled.
Start with simple shots of something that is measured for you
(again, some kind of Color Matching System is good) and
try to get as close to those values as you can in lighting that is known.
Again, as with the section on scanning, this text is meant simply to provide a starting point and
a direction to work in. Do what you can with the tools at hand.
Creating your own art
Depending on you artistic abilities, you may want to try you hand
at creating your own art. There are many benefits to this:
- You will be certain that the file formats, colors, and sizes are correct
- You can usually make changes to the images quickly, if needed, because of your familiarity with the files
- It can be very satisfying
There are many software packages for image creation and manipulation. They generally work in
either raster or vector formats:
- Raster: The majority of graphic file formats are raster images, where the picture is represented
as a series of hexadecimal numbers. Each pixel (or group of pixels) is coded as a string of
information that contains the color information for that small portion of the image.
The file
contains a header that tells the size of the image, file format, possibly things like the
software application that created the image, color space, compression information, and may
even contain a preview of the image, also encoded as a string of hex digits.
PhotoShop and most drawing programs work in raster format. GIF, JPEG, PNG, and
TIF files are all raster formats. Raster files allow tools like "spray-paint", feathering,
different brushes, and a great deal of control over color with regard to brightness, contrast,
selection tools, and a number of photo-editing tools.
- Vector: Some applications work in the language of PostScript where the image is represented
by PostScript commands. For instance, if you drew a circle with a black border and filled the
circle with red, the software application would generate PostScript commands CIRCLE, FILL, and
STROKE with information about the circle. This would be invisible to the person drawing the circle.
The advantage of vector formats over raster is that a great deal of accuracy is possible.
Programs like Illustrator and FreeHand, and CAD programs that output EPS (Encapsulated PostScript)
files can place and move elements in exact increments.
The other advantage vector files have over raster is Bezier curves. First developed for
designing automobiles, Bezier curves allow a point on a path to have handles that alter the
shape of the curve in a precice manner. For instance, a circle has 4 points where the handles on
the points are all the same, allowing the circle its shape. A square has 4 points where the
handles are null, they do not extend the curve in any direction, they merely define the shape.
Choosing a drawing program is a personal choice and many users tend to become devoted to their
software application of choice. I feel that it is always good to be very familiar with a variety
of applications. There are advantages to both raster- and vector-based programs. My personal
choices are FreeHand, Illustrator, and PhotoShop.
Clip Art/Stock Photogaphy
Clip art is a fast way to acquire a large selection of images. There are a huge variety of
clip art libraries to choose from. The Web has some sites that offer free clip art. Many companies
offer disks and CDs that can contain just about any theme with prices ranging from next-to-nothing
to thousands of dollars. Like most eveything else, you get what you pay for.
Before you purchase a clip art library, find out some things about the package:
- What platform the disk is in (IBM, Macintosh, or whatever)
- File format the images are saved as
- Whether the images are color or black and white
- Resolution of the images
- Sizes of the images (in pixels and Megabytes)
©Ken Kaleta 1997, 1998, 1999