Page 15 - CC2017_PS_Look_Inside

Stage 1 Compositing Images and Artwork

Technically speaking, compositing is the process of combining any two or more objects (images,
text, illustrations, etc.) into an overall design. When we talk about compositing in Photoshop, we’re
typically referring to the process of combining multiple images into a single cohesive image. Image
compositing might be as simple as placing two images into different areas of a background file; or it
could be as complex as placing a person into a group photo, carefully clipping out the individual’s
background, and adjusting the shadows to match the lighting in the group.
The ad you’re building in this project requires compositing four digital photographs. You will also
incorporate title treatment and logo files that were created in Adobe Illustrator by other members of
your creative team. The various elements that make up the ad are fairly representative of the type of
work you can (and probably will) create in Photoshop.
Types of Images
There are two primary types of digital artwork: vector graphics and raster images.
Vector graphics are composed of mathematical descriptions of a series of lines and shapes.
Vector graphics are resolution independent; they can be freely enlarged or reduced, and they are
automatically output at the resolution of the output device. The shapes that you create in Adobe
InDesign, or in drawing applications such as Adobe Illustrator, are vector graphics.
Raster images, such as photographs, are made up of a grid of independent pixels (rasters or bits)
in rows and columns (called a bitmap). Raster files are resolution dependent — their resolution is
fixed, determined when you scan, photograph, or otherwise create the file. You can typically reduce
raster images, but you cannot enlarge them without losing image quality.
Line art is actually a type of raster image that is made up entirely of 100% solid areas; the pixels
in a line-art image have only two options: they can be all black or all white. Examples of line art are
UPC bar codes or pen-and-ink drawings.

Screen Ruling
The ad that you will be building in this project is intended to be placed in print
magazines, so you have to build the new file with the appropriate settings for Note:
commercial printing. When reproducing a photograph on a printing press, the Despite their origins
image must be converted into a set of printable dots that fool the eye into believing in pre-digital print
it sees continuous tones. Prior to image-editing software, pictures that were being workflows, these terms
prepared for printing on a press were photographed through a screen to create a grid persist in the digital
of halftone dots. The result of this conversion is a halftone image; the dots used to environment.
simulate continuous tone are called halftone dots. Light tones in a photograph are
represented as small halftone dots; dark tones become large halftone dots.
The screens used to create the halftone images had a finite number of available
dots in a horizontal or vertical inch. That number was the screen ruling, or lines per inch (lpi) of
the halftone. A screen ruling of 133 lpi means that in a square inch there are 133 1 133 (17,689)
possible locations for a halftone dot. If the screen ruling is decreased, there are fewer total halftone
dots, producing a grainier image; if the screen ruling is increased, there are more halftone dots,
producing a clearer image.
Line screen is a finite number based on a combination of the intended output device and
paper. You can’t randomly select a line screen. Ask your printer what line screen will be used before
you begin creating your images. If you can’t find out ahead of time, or if you’re unsure, follow these
general guidelines:
• Newspaper or newsprint: 85–100 lpi

• Magazine or general commercial printing: 133–150 lpi
• Premium-quality-paper jobs (such as art books or annual reports): 150–175 lpi;
some specialty jobs might use 200 lpi or more

Project 1: Composite Movie Ad 25