You can edit a single image, create a montage of imagery from mul-tiple files, or create images entirely within Photoshop by using brushes, filters, and other commands.. ➤ Decide whether
Trang 1IN THIS CHAPTER Buying, and choosing settings for,
a digital camera 18
Working with 16 bits per channel 19
Calculating the correct fi le resolution 20
Creating a new, blank document 21
Creating document presets 23
Saving your fi le 24
Using the Status bar 27
Ending a work session 28
2
pointers for buying a digital camera
and shooting digital photos Following
that, you’ll learn how to calculate the correct
resolu-tion for a file, create a new blank document, create
document presets, save and copy your files, use the
Status bar, and close up shop In the next chapter, you
will learn how to download photos from your camera
and how to use Bridge to open and manage files In
Chapter 4, you will learn how to open and correct your
photos using the Camera Raw plug-in before opening
them into Photoshop
Although Photoshop lets you create, open, edit, and
save files in over a dozen different formats,A–Bon a
frequent basis, you’ll probably encounter or use only
a handful of those formats, namely Photoshop (PSD,
the native Photo shop file format), Photoshop EPS,
Photoshop PDF, JPEG, and TIFF The Large Document
format, or PSB (nicknamed “Photoshop Big”), is used
only for huge files; see the sidebar on page 22
Because Photo shop reads so many different file
formats, you can use the program to open images
from many sources, such as digital cameras, scanners,
drawing applications, and video captures You can edit
a single image, create a montage of imagery from
mul-tiple files, or create images entirely within Photoshop
by using brushes, filters, and other commands
Continued on the following page
A Files can be saved in these formats in
Windows. B Files can be saved in these
formats in the Mac OS.
Trang 2
ptg
Buying a digital camera
If you’re shopping for a digital camera, the first
step is to figure out which model suits your output
requirements and, of course, your budget Two
fac-tors to consider in this regard are a camera’s
mega-pixel value and the size of its digital light sensor
Camera manufacturers usually list the resolution
of a model as width and height dimensions in
pixels (such as 3000 pixels x 2000 pixels) Multiply
the two values, and you’ll arrive at a number in the
millions, which is the number of pixels the camera
captures in each shot This is known as the camera’s
megapixel value If your camera captures a
suffi-cient number of pixels, you’ll be able to print
high-quality closeups and enlargements of your photos
Compact, inexpensive “point-and-shoot”
cam-eras offer few or no manual controls and have a
resolution of 6 to 10 megapixels They capture
enough detail to produce decent-quality 5" x 7"
prints but not larger, and acceptable Web output
Advanced amateur camera models have a
resolu-tion of 8 to 12 megapixels You can get high-quality
8" x 10" prints from these cameras, and they offer
more manual controls
Professional camera models (such as digital
SLRs) have a resolution of 12 megapixels or higher
and can produce high-quality 11" x 14" prints or
larger — but they’re costly More importantly, the
digital light sensors in such cameras are larger
and more sensitive than those in lesser cameras
They record more precise detail and produce a
higher-quality image, with less visual noise
High-megapixel cameras with large sensors aren’t for
everyone — and not just because of their price tag
Images with a high megapixel count have larger file
sizes, take longer to upload from the camera to the
computer, and require a larger hard drive for
stor-age (See our comparison of megapixels and print
size on page 22.) Unless you tend to crop your
photos or output large prints, an 8- to
10-mega-pixel camera will be better suited to your needs
Aside from the megapixel count and the size
of the sensor, make sure the camera you buy can
accommodate a wide assortment of lenses
For more advice about buying a camera, you can
visit the website for PC Magazine (pcmag.com) or
Macworld (macworld.com) Photography magazine
websites are also good sources of information
Choosing settings in your digital camera
You’ve acquired a camera (congratulations!) — now you may want some pointers on how to use it
To get good-quality photographs, in addition to establishing the right lighting conditions, compos-ing the shot artistically, etc., you need to choose your camera settings wisely Here are some basic guidelines:
➤ Medium- and high-end digital cameras let
you choose an ISO setting, which controls
the sensitivity of the camera’s digital sensor
to light (and is comparable to film speed in film photography) High ISO settings tend to produce digital noise in low-light areas, so it’s best to choose the lowest ISO setting that still enables you to get the desired exposure
➤ Decide whether to have your camera capture
the photos in the JPEG format (see pages 425–
426), or even better, as unprocessed raw files.*
➤ Choose a color space for your camera: sRGB
for onscreen or Web output, or Adobe RGB for print output
➤ For JPEG photos, choose a white balance
set-ting that’s appropriate for the lighset-ting condi-tions in which the photos will be shot; the camera will process the image data based on this setting For raw files, you can ignore the white balance setting, as the images won’t be processed inside the camera
➤ If your camera has a histogram display, use
it to verify that your shot was taken with the
correct exposure settings (aperture and shutter
speed) In an overexposed image, insufficient details are captured in the highlight areas; in
an underexposed image, insufficient details are captured in the shadow areas Photoshop can process and adjust only the details that your camera captures (For a discussion of histograms, see pages 203–204.)
Regardless of whether you shoot JPEG or raw photos, most exposure deficiencies, color casts, and other imaging problems can be corrected via the Camera Raw dialog (see Chapter 4) and then the photo can be further corrected via an assortment
of adjustment commands in Photoshop
*Each camera model produces its own variation of a raw file In this book, we refer to such files collectively as “raw files.”
Buying, and choosing settings for, a digital camera
Trang 3
Working with 16 bits per channel
To get good-quality output from Photoshop, a
wide range of tonal values must be captured at
the outset The wider the dynamic range of your
chosen input device, the finer the subtleties of
color and shade it can capture Most advanced
amateur and professional digital SLR cameras
cap-ture at least 12 bits of accurate data per channel
Like cameras, scanners range widely in quality:
Consumer-level scanners capture around 10 bits of
accurate data per channel, whereas the high-end
professional ones capture up to 16 bits of accurate
data per channel
Shadow areas in particular are notoriously
dif-ficult to capture well But if your camera can
cap-ture 12 to 16 bits per channel (or you work with
high-resolution scans), you will have a head start,
because your files will contain an abundance of
pixels in all levels of the tonal spectrum
Photoshop can process files that are in 8, 16, or
32 Bits/Channel mode All Photoshop commands
are available for 8-bit files Most Photoshop
com-mands are available for 16-bit files (e.g., on the
Filter menu, the Liquify and Lens Correction filters
are available, as are some or all of the filters on the
Blur, Noise, Render, Sharpen, Stylize, and Other
submenus, whereas filters on the other submenus
are not) Too few Photoshop commands are
avail-able for 32 Bits/Channel files to make such files a
practical choice
Although you can lower the bit depth of your
files via the Image > Mode submenu, it’s better
to keep them in 16 Bits/Channel mode The
edit-ing and resampledit-ing commands in Photoshop can
degrade the image quality, but the extra pixels in 16-bit images make this less of a problem.A–BThe tonal adjustment commands in particular, such as Levels and Curves, remove pixel data and alter the distribution of pixels across the tonal spectrum
Signs of pixel loss from destructive edits will be more visible in a high-end print of an 8-bit image than in a 16-bit image Because 16-bit images con-tain an ample number of pixels in all parts of the tonal spectrum at the outset, more tonal values are preserved, and the resulting output is higher quality
To summarize, these are some basic facts about 16-bit files to consider:
➤ Photoshop can open 16-bit files in CMYK or RGB mode
➤ 16-bit files can be saved in many formats, such
as Photoshop (.psd), Large Document (.psb), Photoshop PDF (.pdf), PNG (.png), TIFF (.tif), and JPEG 2000 (.jpf)
➤ From the Mac OS, you can print 16-bit files, provided your printer supports 16-bit printing
➤ For commercial print output, your output service provider may request 8-bit files, in which case you will need to convert them after image-editing
Note: If system or storage limitations prevent you from working with 16-bit images, consider follow-ing this two-stage approach: Perform the initial tonal corrections (such as Levels and Curves adjust-ments) on the 16-bits-per-channel image, then convert it to 8 bits per channel for further editing
B Here, the same Levels adjustment was made to a 16-bit version of the same image Because of the higher bit depth, the smooth tonal transitions were preserved.
A As a result of a Levels command adjustment to this
8-bit image, some image data was discarded, as shown by
the spikes and gaps in the histogram.
Trang 4
Calculating the correct file
resolution
Resolution for print
If you shoot digital photos, your camera will preserve
either all the pixels that are captured as raw files or
a portion of the pixels that are captured as small,
medium, or large JPEG files If you use a scanner to
acquire images, you can control the number of pixels
the device captures by setting the input resolution in
the scanner software
High-resolution photos contain more pixels, and
therefore finer details, than low-resolution photos,
but they also have larger file sizes, take longer to
render onscreen, require more processing time to
edit, and are slower to print Low-resolution images,
however, look coarse and jagged and lack detail
when printed Your files should have the minimum
resolution to obtain the desired output quality from
your intended output device at the desired output
size — but not much higher There are three ways to
set the resolution value for your digital files
➤ If you open raw digital or JPEG photos into the
Camera Raw dialog, which we highly recommend,
you can specify an image resolution there See
page 66
➤ After opening your files into Photoshop, you can
change the image resolution in the Image Size
dialog (see pages 122–124)
➤ When scanning photos, you’ll set the image
resolution using the scanning software for that
device
The print resolution for digitized images (from a
camera or scanner) is calculated in pixels per inch
(ppi) A–C For output to an inkjet (desktop) printer,
the file resolution should be between 240 and
300 ppi
Commercial print shops have specific
require-ments for their particular output devices, so it’s
important to ask them what resolution and halftone
screen frequency settings they’re going to use before
choosing a resolution for your files For a grayscale
image, the proper resolution will usually be around
one-and-a-half times the halftone screen frequency
(lines per inch) setting of the output device, or 200
ppi; for a color image, the resolution will be around
twice the half tone screen frequency, or 250–350 ppi
A 72 ppi
B 150 ppi
C 300 ppi
Trang 5
Resolution and dimensions for the Web
Choosing the correct file resolution for Web output
is a no-brainer: It’s always 72 ppi
Choosing the correct dimensions for Web output
requires a little more forethought, because it
depends on how your Photoshop images are
ulti-mately going to be used in the Web page layout To
quickly create a document with the proper
dimen-sions and resolution for Web output, choose a
preset in step 3 at right To determine a maximum
custom size for a Photoshop image to be displayed
on a Web page, first estimate how large your user’s
browser window is likely to be, then calculate how
much of that window the image is going to fill
Currently, the most common monitor size is 1024
pixels wide by 768 pixels high Most viewers have
their browser window open to a width of
approxi-mately 1000 pixels If you subtract the space
occupied by the menu bar, scroll bars, and other
controls in the browser interface, you’re left with
an area of up to 800 x 600 pixels; you can use those
dimensions as a guideline If your Photoshop file
is going to be used as a small element in a Web
page layout, you can choose smaller dimensions
Creating a new, blank document
In these instructions, you will create a new, blank document You can drag and drop or copy and paste imagery into this document from other files,
or draw or paint imagery by hand using brushes
The images can then be edited with Photoshop commands, such as effects and filters
To create a new, blank document:
1 Choose File > New (Ctrl-N/Cmd-N) The New
dialog opens.A
2 Type a name in the Name field.
3. Do either of the following:
Choose a preset size option from one of the
three categories on the Preset menu: the
Default Photoshop Size; a paper size for com-mercial and desktop printers; or a screen size for Web, mobile, film, and video output Next, choose a specific size for that preset from the
Size menu
Choose a unit of measure from the menu next
to the Width field; the same unit will be chosen automatically for the Height (or to change the unit for one dimension only, hold down Shift
while choosing it) Next, enter custom Width and Height values (or use the scrubby sliders).
Continued on the following page
A In the New dialog, enter
a file Name; either choose
a Preset size or enter custom Width, Height, and Resolution values; choose RGB Color Mode and a Background Contents option;
and choose a Color Profile.
Trang 6
4 Enter the Resolution required for your target
output device — be it an imagesetter or the
Web For the Web, enter 72; for print output,
see our discussion of resolution on page 20
You can use the scrubby slider here, too
5 Choose a document Color Mode (RGB Color is
recommended), then from the adjacent menu,
choose 8 bit or 16 bit as the color depth (see
page 19) You can convert the image to a
differ-ent color mode later, if needed (see “Photoshop
document color modes” on pages 3–4)
6 Note the Image Size, which is listed on the
right side of the dialog If you need to reduce
that size, you can choose smaller dimensions,
a lower resolution, or a lower bit depth
7. For the Background of the image, choose
Background Contents: White or Background
Color; or choose Transparent if you want the
bottommost tier of the document to be a layer
(To choose a Background color, see Chapter 11
To learn about layers, see Chapter 8.)
8 Click the Advanced arrowhead, if necessary, to
display additional options, then choose a Color
Profile This list of profiles will vary
depend-ing on the document Color Mode (Note: you
can also assign or change the profile later in
the Edit > Assign Profile dialog To learn more
about color profiles, see pages 10–11 and 16.)
For Web or print output, leave the Pixel Aspect
Ratio on the default setting of Square Pixels
For video output, choose an applicable option
(see Photoshop Help)
9 Click OK A new, blank document window
appears onscreen To save it, see page 24
➤ To force the New dialog settings to match those
of an existing open document, open the New
dialog, then from the bottom of the Preset
menu, choose the name of the document that
has the desired dimensions
➤ If the Clipboard contains graphic data (say,
that you copied from Adobe Photoshop or
Illustrator), the New dialog will
automati-cally display the dimensions of that content
Choosing Clipboard from the Preset menu in
the New dialog accomplishes the same thing If
you want to prevent the Clipboard dimensions
from displaying, and display the last-used file
dimensions instead, hold down Alt/Option as
you choose File > New
MEGAPIXELS, RESOLUTION, AND PRINT SIZES
Image Megapixels in Inches (rounded off)*
150 ppi 13 x 20 16 x 22 17 x 24 18 x 28
300 ppi 7 x 10 8 x 11 8 x 13 9 x 14
* These print sizes are approximate For a more exact
list-ing, search the Web for “megapixels to print size chart.”
PHOTOSHOP BIG
In Photoshop, you can create and save fi les as large
as 300,000 x 300,000 pixels — or over 2 gigabytes (GB) — and they can contain up to 56 user-created chan-nels The Large Document (.psb) format is designed specifi cally for saving these gonzo fi les, but they can
be opened and edited only in Photoshop (versions CS through CS5)
What can you do with PSB fi les? If you have the disk space to store and work with them and have access to a wide-format printer that can output super-large images (up to 32,000 x 32,000 pixels), great In order to output a PSB fi le on an ordinary printer, though, you would have to lower its resolu-tion drastically (remember to duplicate the fi le fi rst)