Scanning Photo Basics
Lesson 1: Choosing a scanner
Lesson 2: Installing your scanner
Lesson 3: Calibrating your scanner
Lesson 4: Editing your photos
Lesson 5: Using special effects filters
Lesson 6: Preparing your photos for email or the web
Lesson 1: Choosing a scanner
Explore how a scanner works and what
determines its quality.
Welcome to Scanning Photos 101
So you finally bought yourself a scanner and
have big plans to scan treasured photos and share them with your friends and
family online. What do you need to know?
This course will get you up and running with
your scanner and show you how to get the best quality results, plus tips on how
to share your photos on the Web or over e-mail. Before we dig in, let’s review
how a scanner works.
A scanner works by passing a bright light
across an image. The light from that image reflects on rows of mirrors. The
mirrors send the light to a charge-coupled device (CCD), which converts the
light to voltage. From there, the voltage is sent to an analog/digital converter,
and then to your computer for storage and editing.
The quality of the CCD determines the quality
of the scanner. The CCD acts as the main gateway between the photograph on the
scanner bed, and the file stored on a computer’s hard drive. The image brightness,
color depth, and clarity depend on the accuracy and number of sensors in the
CCD (as well as the brightness of the scanner lamp).
How to choose a scanner
When it comes to judging specs, be sure to
read the box carefully. Some manufacturers quote the interpolated resolution
rather than the optical resolution. The former conjures up pixels where none
exist, by mathematically approximating the pixel value based on its neighbors,
while the latter figure represents the actual number of photo-sensitive sites
on the sensor. Optical density can also be a tricky spec. It’s a measurement of
the range of tonal values a scanner can capture, on a scale of 0 to 4.0; the
closer to 4.0, the more detail you’ll see in the highlights and shadows. But
there’s no standard defining the scanner settings with which the measurements
are taken, so we can take the manufacturer’s quote as
only a rough approximation.
The breadth and depth of scan controls, as
well as the software bundle, can make a huge difference in your scan quality.
For instance, to get the maximum tonal range, you should perform color and
exposure adjustments at scan time whenever possible rather than during postprocessing--in Photoshop, for example--to minimize
image degradation. Similarly, if you have a ton of photos to scan, you
definitely need a driver with good batch-scanning capabilities and
well-designed film holders. In addition to basic apps, most scanners come with
some sort of additional software, even if it’s only a modest imaging program
such as Adobe Photoshop Elements.
Take some time to read about your scanner
with this information in mind.
Lesson 2: Installing your scanner
Explore
what needs to happen in order to access your scanner from your computer.
Installing your scanner for the first time
When you first hook up your scanner, you
should follow the manufacturer’s installation instructions precisely, so that
the scanner’s software drivers are loaded correctly.
Note:
Drivers are the organized routines that allow the scanner and computer to
synchronously perform their related tasks. When you install your scanner
software, these small files automatically load into the computer. Some software
programs install the same driver; this causes older drivers to overwrite the
newer versions. However, for your scanner to work, the computer must have
correct versions of all relevant drivers.
Your scanner will come with a basic scanning
utility program that will allow you to access and control the scanner so you
can make setting changes and execute scans. This software displays the scanner
image area and allows you to preview the image before the scan finishes and
gets saved to your hard drive. It will also allows you
to adjust resolution and color depth.
Note:
If you have photo editing software installed on your computer, you may be able
to access the scanner directly from within that software as well. This scanner
control features usually appears when you select the
‘Acquire’ option in the photo editing software.
Scanning Guidelines
Now that you’re ready to begin scanning, keep
in mind the following guidelines:
You can scan images bound for the Web or
other computer applications such as PowerPoint slideshows or CD-ROM images at
72 dpi.
You can scan images bound for inkjet printers
at 150 to 200 dpi. On the other hand, you can scan photographs that have a lot
of flesh tones or details closer to the 200 dpi range.
For professionally printed images, for a
company brochure or poster, scan them according to the print house’s requirements,
between 300 and 1200dpi.
All photographs should be scanned at the
highest color mode possible. Look for a special setting in your scanning
software called “Full Color Photograph,” or “16.7 million colors” or “24-bit
Color.” Avoid scanning a photograph at 256 Colors, or 8-bit color. It will look
blotchy and have incorrect color blends.
Lesson 3: Calibrating your monitor
Learn
how to calibrate your monitor to set appropriate darkness and lightness for
working with photos.
Calibrating your monitor
Have you ever noticed that images on your
computer look lighter or darker than they do on other computers? Before you
begin the process of editing your photos, you need to calibrate your monitor to
ensure you’re seeing the most accurate rendition of what you’ve scanned. This
process is called Gamma Correction.
Computer monitors have varying degrees of
brightness. Some monitors exaggerate an image’s dark tones. You may find that
adding brightness to an image only makes it looks washed out on another
computer. For example, if your image has an RGB color setting of Red: 100,
Green: 50, and Blue: 50, you’d think that every computer would show the red twice
as intense as the green and blue, but that is not always the case. Gamma
correction compensates for this intensity difference.
Photo editing programs usually offer a
calibration feature that allows you to set your monitor to a general darkness
and lightness intensity. Some software packages also offer calibration programs
that adjust Gamma by displaying a band that fades from black to white and then
prompt you to select certain points along the band. This process shows the
software how to manage the lightest, darkest, and midpoint color ranges when
viewing an image.
There is a wide difference between the
typical Gamma of a Macintosh monitor and that of a PC monitor. An image created
on a PC may look dark on a Mac, and conversely, an image created on a Mac may
look too bright on a PC. The typical Gamma correction value for a PC is 2.2,
while Macs are usually set at 1.8
Lesson 4: Editing your photos
Explore
techniques for editing your photos.
Now it’s time to polish the photos you’ve
scanned and saved.
You can use image editing software like
Photoshop or PaintShop Pro, if you have them. Or your
scanner may be bundled with a basic image editing program like Photoshop
Elements.
You can also try a free photo editing program
like IrfanView.
Tip:
Make a backup copy of all your photos before your start editing. Put the
untouched scanned image files aside (burning them onto a CD is a good choice).
This way, you can fearlessly make bold changes to your photos knowing that
you’ve got the originals stashed away in case you ‘go too far’ with the edits.
Most graphics program offer
a number of techniques for altering images. A few common ones include
correcting the color of your image with level equalization, color curve
adjusting, color balance, and brightness/contrast.
- With
level equalization, you can adjust the brightness and contrast in an image
and make the midtones darker or lighter to bring
out the detail. Some applications refer to this tool as “levels” or
“equalization.”
- The
color curve adjustment tool, sometimes called “curves,” allows you to map
pixels to new bright and dark values by dragging along the points in a
curve. All the hues surrounding the point you drag on the curve will also
adjust to some degree. This makes the brightness change look more natural.
- Color
balance allows you to adjust the different color ranges, to bring out the
colors at one end of the range or the other.
- Brightness/contrast
tools are the easiest tools to use. They increase both the image pixel
luminance, and the difference between the lightest and darkest pixels.
You can also correct an image with pixel
editing tools such as sharpness and cropping:
- The
sharpen tool makes an image look crisper, less blurry. Watch out, though,
as too much sharpness creates a “frosty” halo around objects, which can be
just as unattractive as the blur that the tool was used to correct. The unsharp mask tool sharpens subtly and, in the instance
of blurred scans, can work wonders.
- Cropping
an image removes part of the picture. For instance, if all you care about
is the basketball player in the center of your scan, then crop out any
extraneous background, so that your subject matter becomes the main focus
of your image.
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Lesson 5: Using special effect filters
Explore
how to use special effect filters to alter your photos.
In the previous lesson we covered the
essentials of photo editing: cropping, contrast, sharpening, and color balance.
Most image editing programs also offer you a
variety of “filters” you can use to distort or modify your photos in fun and
exciting ways. Some filters will make your image appear to be an oil or
water-color painting. Another will make it appear to be an old sepia-toned
black and white photo. A wide variety of eye-catching lighting effects are also
available.
Using these filters are
certainly not necessary, but it can be a lot of fun trying them out.
ALERT:
Again, it’s a good idea to make a copy of your photos before experimenting with
filters. Or alternatively, if you open a photo file and make radical changes,
you can just choose “Save As” and re-name the file so that your original file
is retained without any changes.
Most current graphic editing programs let you
select a portion (or all) of your photograph and resize it, distort it, and
apply effects it, while leaving the rest of the image untouched. Also,
depending on the program you’re using, you can copy a portion of the photograph
to the clipboard and then paste it into a new ‘layer’ so that you can restrict
the effects of the filter to a specific layer and leave the rest of the photo
unchanged.
When you paste a selection into another
image, or even into the same image, you can specify how opaquely the
overlapping layers, or objects, will combine. When you paste in a new layer
into a graphic editing program, you’ll see a dropdown menu called Merge, or
Blend Mode. This dropdown menu will have options such as Add (meaning, add the
two colors together), Multiply, Saturation, Texturize, etc. Each option will apply a unique
mathematical formula to determine how the image layers interact with each other
color-wise.
You can have a lot of fun with these tools,
but remember: a little filtering goes a long way.
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Lesson 6: Preparing your photos for the e-mail and the web
Learn
how to save your photos in the best format and file size for e-mailing and the
Web.
One of the easiest ways to share your photos
with friends and family is to send them via email. However, your newly scanned/edited
photos are not ready to be e-mailed. This is because the image files are
probably quite large (anywhere from 1 megabyte to 5 or more depending on the
resolution you selected when you scanned).
You don’t want to e-mail such large files
because they take too long to transfer, and many people can’t receive big files
because of e-mailbox size limitations. So the answer is to reduce the filesize of your images before emailing. They’ll still look
great, and your friends will thank you for not clogging their inbox with
massive files.
Here’s how to do it:
1.First, reduce the actual size of your image. Since
your recipient will be viewing the photo on a computer, it should be small
enough so that it fits completely on a computer screen. To do this, open the
image file in your image editor. Then change the size--for emailing, the image
shouldn’t be any more than 600 - 700 pixels wide.
o
In Photoshop,
this is done with the “Image Size” option, under the Image pull-down menu.
o
In IrfanView, this is done with the “Resize/resample” option,
under the Image pull-down menu.
2.The last step is to compress the file into a
smaller-sized ‘e-mailable’ file. To do this:
o
In Photoshop:
Choose “Save for Web” under the File pull-down menu, select the JPG format, and
set the Quality to 50 (or less).
o
In IrfanView, choose “Save As” under the File menu, select the
JPG format, and set the Save Quality to 50 (or less).
ALERT:
When you save these new e-mailable files, give them a
different name, because you don’t want to replace or overwrite your original
full-sized version.
You’ll notice that these smaller compressed
image files still look great even though they’re a tenth of the filesize of the original file.
Any images you put on a web site should also
go through this process so that your site visitors will be able to download
your photos more quickly. But note that many of the new photo gallery web
services (such as
Flikr or Webshots
) will do the resizing and compression for you. So you can just upload your
full-sized/uncompressed images and they’ll automatically produce a
quick-loading version to display in your gallery. Very convenient!
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