design basics
12–25
image types
28–31
file formats
32–33
elements
26–71
file types
32–35
saving images
34–35
colour
72–111
working with images
36–51
pre-press
112–139
image manipulation
52–55
production
140–163
type
56–71
finishing
164–183
saving images When a designer creates or works on an image, one of the first and most important choices to be made is the file format in which it should be saved. However, there is much more to saving an image; a designer also needs to consider which colour space the image is to use, as well as other factors, such as the anticipated print size and resolution. Here, we examine some of the variables to bear in mind when making such decisions. saving for print For printing, the CMYK colour space is normally used, as this corresponds to the four process colours used during printing. However, some printers prefer to receive artwork in the RGB colour space so that they can perform the colour conversion using profiles they have generated for their print presses. Images should be 300ppi rather than dpi as they are made of pixels and not dots, even though they will print as dpi.
When saving a file it is possible to choose compression settings. Saving with no compression offers no further options, but saving as ZIP or LZW (Lemple-Zif-Welch), a lossless compression, or JPEG, a lossy compression, will allow layers to be compressed, as not all applications can read files saved in layers. ‘Byte order’ refers to platform compatibility; most applications can open files saved for either IBM PC or Macintosh byte order, but if in doubt ask the end user (for example, printer) for their preference or limitations.
saving a TIFF file When saving a TIFF, a designer can choose whether to save the image layers or compress them. If the layers are to be maintained, the secondary save screen provides a choice of compression methods for saving the file to reduce its size. primary options Firstly you select TIFF as your saving option, deciding whether or not to save as layers. Desktop
layers Saving as layers preserves the individual layers, but creates a larger file. Not saving as layers, flattens the image, but creates a smaller file.
secondary options Once you’ve decided to save as a TIFF, you’ll be presented with additional file choices.
BMP
gavinthomas
CompuServe GIF Photoshop EPS
Applications
JPEG
TIFF Options Image Compression
compression Determines the level of compression, if any.
PCX Movies
Photoshop PDF Photoshop 2.0
Music
Photoshop RAW
Documents
PICT File PICT Resource
OK
NONE Cancel
LZW ZIP JPEG Quality:
Maximum
small file
large file
Pixar PNG Scitex CT Format:
Byte Order
Targa TIFF
IBM PC
Photoshop DCS 1.0 Save:
As a C
Photoshop DCS 2.0
Alpha Channels
Spot Colors
Layers Color:
Use Proof Setup: Working CMYK Embed Color Profile: Dot Gain 20%
New Folder
Cancel
Save
byte order Most programs can open files saved in either format; it is, however, safer to save the file in the platform format that it will be used in.
Macintosh Save Image Pyramid Save Transparency Layer Compression RLE (faster saves, bigger files) ZIP (slower saves, smaller files) Discard Layers and Save a Copy
image pyramid Preserves multi-resolution, but this isn’t supported by many programs.