Adobe Photoshop 7.0 for Photographers
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Jump to button
ImageReady™ 7.0 is a stand-alone application, that is installed with Photoshop 7.0. Click-
ing on the ‘Jump to’ icon will switch you from Photoshop to ImageReady™ and vice
versa, without having to exit from the current program. The file will always continue to
remain open in the previous program and you can select different programs to jump to
from the File > Jump to menu. Upon installation, applicable application aliases are in-
stalled in the Photoshop 7.0 > Helpers > Jump to Graphics Editor folder, i.e. Adobe
Illustrator™ from Photoshop or HTML editing programs like Adobe GoLive™ from
ImageReady™. If the other program is not currently open, the Jump to button will launch it.
Summary
The tools and palettes mentioned here will be cropping up again over the following
chapters. Hopefully the later tutorials will help reinforce the message. In order to
help familiarize yourself with the Photoshop tools and Palette functions, help dialog
boxes will pop up after a few seconds whenever you leave a cursor hovering over
any one of the Photoshop buttons or tool icons (see: Show Tool Tips in the General
Preferences). A brief description is included in the box and tools have their keyboard
shortcuts written in brackets.
Figure 6.32 The Photoshop Color Picker, which is shown with a ‘grayed out’ color field because Gamut
Warning is currently checked in the View menu. The alert icon beside the newly selected foreground
color tells you it is out of gamut. If you check on the cube icon below, this will make the selected
color jump to the nearest HTML web safe color. If you check the Only Web Colors box the Color
Picker will display the restricted web safe color palette.
Show web safe colors only
The color field area New selected color Out-of-gamut warning
Jump to nearest web safe color
HTML color reference
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File formats
File Formats
Chapter Seven
P
hotoshop supports just about any image file format you care to mention.
Choosing which format to output your images to should be determined by
what you want to do with that file and the list can then be further narrowed
down to a handful of recognized formats, appropriate to your needs. You may want
to choose a format that is intended for prepress output, or screen-based publishing,
or maybe you wish to use a format that is suitable for image archiving only. Screen-
based publishing is a rapidly growing sector of the publishing industry and it is predicted
that the percentage of designers operating in cross-media publishing, i.e. screen and print,
will soon overtake those working in print design only. The Save for Web dialog contains
a lot of useful web format tools and Photoshop 7.0 ships with ImageReady™ 7.0,
which is a stand-alone web image editing program, and you can switch back and
forth between Photoshop 7.0 and ImageReady™ 7.0 to produce optimized, sliced images,
animated GIFs and even rollover buttons complete with JavaScript code. Adobe
InDesign™ and Adobe GoLive™ enable you to share Photoshop files between these
separate applications and see changes made to a Photoshop file be automatically updated
in the other program. This modular approach means that many Adobe graphics programs
are able to integrate with each other.
While an image is open in Photoshop, it can be manipulated without being limited
by the range of features supported in the original source format. If you open an EPS
format image in Photoshop and simply adjust the levels and save it, Photoshop will
overwrite the original. But you can also edit the same EPS image in Photoshop,
adding features such as layers or adjustment layers. When you come to save, you
will be shown the Save dialog shown in Figure 7.1. This reminds you that the file
contains features that are not supported by the EPS file format and alerts you to the
fact that if you click Save now, not all the components in the image (i.e. layers) will
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Adobe Photoshop 7.0 for Photographers
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be fully saved. This is because while you can save the file as an EPS, the EPS format
does not support layers and the document will therefore be saved in a flattened state.
If I were to select the native Photoshop file format and check the Layers box, then it
will become possible for me to now save this version of the image in the native
Photoshop format and preserve the layer features. Only the Photoshop, PDF and
TIFF formats are capable of supporting all the Photoshop features such as vector
masks and image adjustment layers. Saving in the native Photoshop format should
result in a more compact file size, except when you save a layered Photoshop file
with the Maximize Backward Compatibility checked in the preferences. Figure 7.18
at the end of this chapter contains a summary of file format compatibility with the various
Photoshop features.
Figure 7.1 The Photoshop Save dialog box.
TIFF (Tagged Image File Format)
This is the most universally recognized, industry-standard image format. Labs and
output bureaux generally request that you save your output image as a TIFF, as this
can be read by most other imaging computer systems. If you are distributing a file
for output as a print or transparency, or for someone else to continue editing your
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File formats
187
master file, you will usually be safest supplying it as a TIFF. Photoshop TIFFs now
support alpha channels and paths, although bureaux receiving TIFF files for direct
output will normally request that a TIFF file is flattened and saved with all alpha
channels removed. An uncompressed TIFF is about the same size as shown in the
Image Size dialog box. The TIFF format in Photoshop offers several compression
options. LZW (which appears in the Save dialog box) is a lossless compression op-
tion. Data is compacted and the file size reduced without any image detail being lost.
Saving and opening will take longer when LZW is utilized, so some bureaux will
request that you do not use it. ZIP is another lossless compression encoding that like
LZW is most effective where you have images that contain large areas of a single
color. JPEG compression is a lossy compression method and is described more fully
later. TIFF has the benefit of being able to support transparency and all of the
Photoshop 7.0 features (should you wish to). The byte order is chosen to match the
computer system platform the file is being read on. However, most software programs
these days are aware of the difference, so the byte order is far less relevant now. The main
formats used for publishing work are TIFF and EPS (and also the native Photoshop
file format in an Adobe InDesign™ or Illustrator™ workflow, where Maximize Back-
wards Compatibility must be switched on). Of these, TIFF is the more flexible format,
but this does not necessarily imply that it is better. The PDF file format is also gaining
popularity for DTP (desktop publishing) work. TIFF files can readily be placed in
QuarkXPress™, PageMaker™, InDesign™ and any other DTP or word processing docu-
ment. The TIFF format is more open though and unlike the EPS format, you can make
adjustments within the DTP program as to the way a TIFF image will appear in print.
Figure 7.2 The TIFF save options allow you
to apply LZW, ZIP or JPEG compression to
a file. The Save Image Pyramid option will
save a pyramid structure of scaled-down ver-
sions of the full-resolution image. TIFF pyra-
mid-savvy DTP applications (there are none
I know of yet) will then be able to display a
good quality TIFF preview, but without hav-
ing to load the whole file. If an open image
contains alpha channels or layers, the Save
dialog in Figure 7.1 will indicate this and you
can keep these options checked to preserve
these in a TIFF save. If the File Saving prefer-
ences have Ask Before Saving Layered TIFF
Files switched on a further alert dialog will
warn you after clicking OK to the TIFF op-
tions the first time you save a layered TIFF.
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Adobe Photoshop 7.0 for Photographers
188
EPS
EPS (Encapsulated PostScript) files are the preferred format for placing large color
separated files within a page layout document. The EPS file format uses a low reso-
lution preview to display the image on screen while the image data is written in the
PostScript language used to build the output on a PostScript device. The image data
is ‘encapsulated’ which means it cannot be altered outside of the program that cre-
ated it (i.e. Photoshop). The downside of using EPS is that all the PostScript image
data must be processed by the RIP every time you make an output, even if only a
smaller amount of data is required to produce a proof and EPS files can take longer
to process than a TIFF. However, you get an almost instantaneous rendering of the
image preview when editing a DTP document on the screen. The saving options
include:
Preview display: This is a low resolution preview for viewing in the page layout.
The choice is between None, a 1-bit/8-bit TIFF preview which is supported on both
platforms, or a 1-bit /8-bit/JPEG Macintosh preview. I recommend the 8-bit preview
mode or JPEG Macintosh preview if working on the Mac.
Encoding: The choice is between ASCII or Binary encoding. ASCII encoding is
more generic but generates large files and is suited to PC platforms only. Binary
encoded files are half the size of ASCII encoded files and can therefore be pro-
cessed more quickly. JPEG coding produces the smallest sized, compressed files.
Use JPEG only if you are sending the job to a Level 3 PostScript printer. Bear in
mind that image quality will become significantly degraded whenever you select a
lower quality JPEG compression setting.
Include Halftone Screen and Include Transfer Functions: For certain subjects,
images will print better if you are able to override the default screen used on a print
job. Transfer functions are similar to making Curves image adjustments. Check these
boxes if you want information entered to override the default printer settings. They
do not alter the screen appearance of the image and are adjusted to accommodate dot
gain output. The screen and transfer functions are defined in Photoshop. If printing
the same file to two different printers, you may wish to save one file for the final
print job as it is and save another version for the proof printer specifying the use of
preset transfer functions to compensate for the different printing characteristics.
PostScript Color Management: This will enable PostScript Level 2 devices or higher
to read the Grayscale, RGB or Lab profiles embedded in Photoshop and convert as
necessary. But I believe it is better to let Photoshop handle the color management
and conversions.
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File formats
189
If any vector data is present in the document this can be interpreted such that the
vector information will be rasterized in the EPS file. As usual, clipping paths can be
saved in an EPS file – a clipping path will act as an outline mask when the EPS file
is placed into a page layout program. If you have a work path saved in the Paths
palette it can be specified to be used as the clipping path from within Photoshop.
DCS
Figure 7.3 The DCS 2.0 Format options dialog box.
QuarkXPress also uses a version of the EPS format known as DCS (Desktop Color
Separations). The DCS 1.0 format generates five separate files: one preview composite
and four-color separation files. It can be difficult to manage all these individual color
plate files, especially when there are a lot of images in a folder. The DCS 2.0 format
is a self-contained file containing the preview and separations. Crucially, DCS 2.0
supports more than four color channels, i.e. spot colors and HiFi color.
Photoshop PDF
The PDF (Portable Document Format) is an electronic publishing format used
primarily for the distribution of document layouts, although it is fast gaining accep-
tance for prepress work and is the principal format for Adobe Acrobat™ and Adobe
Illustrator™. Adobe Acrobat Reader is a freeware program and widely available to
install from consumer magazine CDs or can be downloaded from the Adobe website.
CD Presentations, like that found on the Adobe Photoshop Tutorial CD, use the
Acrobat PDF format to display electronically published documents. Adobe Acrobat
can reproduce pages designed in InDesign or Illustrator to be viewed as self-
contained documents. Best of all, Acrobat documents are small in size and can be printed
at high resolution. The main selling point of PDF is its independence of computer
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Adobe Photoshop 7.0 for Photographers
190
operating system and the fonts installed on the client’s computer. I can create a docu-
ment in PageMaker™ and export as an Acrobat PDF using the Acrobat Distiller
program (Distiller is part of the Acrobat program and also included as a separate,
stand-alone application with PageMaker). Anyone who has installed the Acrobat Reader
program can open the PDF document I supply and see the layout just as I intended it to be
seen, with the pictures in full color plus text displayed using the correct fonts. The Photoshop
PDF format (see Figure 7.4) can save all Photoshop 7.0 features, with either JPEG or
lossless ZIP compression and is backwards compatible in as much as it will save a flat-
tened composite for viewing within programs that are unable to fully interpret the
Photoshop 7.0 layer information.
The PDF format in Photoshop is particularly useful for sending Photoshop images to
people who don’t have Photoshop, but do have Acrobat Reader on their computer. If they
have a full version of Acrobat they will even be able to conduct a limited amount of
editing, such as changing a text layer slightly. Photoshop is also able to import or append
annotations from Adobe Acrobat. The Include Vector Data options allow you to embed
text layer fonts and vector layer information. Use the Use Outlines for Text option only if
you are dealing with an application that will have trouble interpreting the embedded font
information.
Figure 7.4 The PDF Options dialog. You can save nearly all of the Photoshop 7.0 features in the PDF
format and include password security to restrict file access to unauthorised users.
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File formats
191
Figure 7.6 If you try to open a
generic Acrobat PDF from within
Photoshop by choosing File >
Open, you will see the PDF Page
selector dialog, shown bottom left.
Select individual or multiple pages
to rasterize as images in Photoshop.
If you choose File > Import > PDF
Image, you can extract the individual
images (or Import All) from a self-
contained PDF document.
Figure 7.5 The Photoshop PDF Security options.
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Adobe Photoshop 7.0 for Photographers
192
PDF security
The PDF security options allow you to restrict file access to authorized users only –
you can introduce password protection to open a file in either Acrobat or Photoshop.
And you can also have a secondary password for permission to print or modify the
PDF file in Acrobat. Note that this level of security only applies to reading the file in
Acrobat. You can only password protect the opening of a PDF file in Photoshop.
Once opened in Photoshop, it will be fully editable. There are two security options:
40-bit RC4 for lower-level security and compatibility with versions 3 and 4 of Acrobat
and 128-bit RC4, for higher security and Acrobat 5 only.
Importing multi-page PDF files
The Photoshop Parser plug-ins enable Photoshop to import any Adobe Illustrator,
EPS or generic single/multi-page PDF file. Complete PDF document pages can be
rasterized and batch processed to be saved as Photoshop image document files. Use
File > Import > PDF Image to extract all or individual image/vector graphic files
contained in a PDF document as separate image files (see Figure 7.6).
Figure 7.7 Two JPEG images: both have the same pixel resolution and both have been saved using the
same JPEG quality setting. Yet the cloud image will compress to just 21 kilobytes, while the windows
image is almost three times bigger at 59 kilobytes. This is because of all the extra detail contained in
the street picture. The more contrasting sharp lines there are, the larger the file size will be after
compression. For this reason it is best not to apply too much unsharp masking to an image before you
save it as a JPEG. If necessary, you can deliberately apply blur to a background in Photoshop to remove
distracting detail and thereby reduce the JPEG size.
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File formats
193
PICT
PICT is primarily a Macintosh file format which while it can be read by PC versions
of Photoshop, it is not a format for DTP work, although it has some uses in certain
multimedia authoring applications. The PICT format utilizes lossless Run Length
Encoding compression – areas of contiguous colors (i.e. subjects against plain color
backgrounds) compress more efficiently without any image degradation, although
files can be compressed using various levels of JPEG compression. I would add
though that there is nothing about PICT which the native Photoshop file format can-
not do better and there are also some pixel size limitations with the PICT format.
JPEG
The JPEG (Joint Photographic Experts Group) format provides the most dramatic
way to compress continuous tone image files. The JPEG format uses what is known
as a ‘lossy’ compression method. The heavier the compression, the more the image
becomes irreversibly degraded. For example, an 18 MB, 10" × 8" file at 300 ppi
resolution can be reduced in size to around 1 MB with hardly any degradation to the
quality of image. If you open a moderately compressed JPEG file and examine the
structure of the image at 200%, you will probably see that the picture contains a
discernible checkered pattern of 8 × 8 pixel squares. This mosaic pattern will easily
be visible at actual pixels viewing when using the heaviest JPEG setting. Compres-
sion is more effective if the image contains soft tonal gradations as detailed images
do not compress quite so efficiently and the JPEG artifacts will be more apparent.
Once an image has been compressed using the JPEG format, it is not a good idea to
resave it as a JPEG a second time, because this will only compound the damage
already done to the image structure. Having said that, providing the image pixel size
remains identical, the destruction caused by successive overwriting is slight (except
in those areas of the picture which have been altered). The JPEG format should
mainly be used to save a copy of an image whenever you want to reduce the file size
so as to occupy a much smaller space than the original. You normally want to com-
pact a file in this way for inclusion on a web page, faster electronic distribution, or
saving a large file to a restricted amount of disk space. Some purists will argue that
JPEG compression should never be used under any circumstances to save a photo-
graphic image. If an EPS or TIFF file is saved with JPEG file compression this can
cause problems when sending a file to some older PostScript devices, so that is one
good reason for not using JPEG. But otherwise, the image degradation is barely
noticeable at the higher quality compression settings, even when the image is viewed
on the screen in close-up at actual pixels viewing, never mind when it is seen as a
printed output. Wildlife photographer Steve Bloom once presented two Pictrograph
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