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Table Of Contents
13.6 Image Quality
What is image quality in PlanetPress Design?
Image quality in PlanetPress Design refers to the type of content a bitmapped image resource contains: line
art or photo. This determines the type of compression PlanetPress Design applies to the bitmapped image
resource. Compression reduces the size of the image resources, and consequently reduces the overall size of
the document.
13.6.1 Line Art Quality
In line art quality, the edges of different elements of the image are clearly visible and sensitive to any
increase or decrease in pixel dimensions that occurs through resampling. As an example of line art, think of a
corporate logo. A logo typically uses flat areas of color with each area clearly distinguished from the other.
PlanetPress Design uses a lossless compression for line art quality images. A lossless compression preserves
all image information.
13.6.2 Photo Quality
In photo quality, edges of elements are not as clearly delineated and are consequently less sensitive to any
increase or decrease in pixel dimensions that occurs through resampling. As an example of photo quality,
think of a photograph of a natural object or landscape; there are many subtle tones and gradations, even
along the edges between elements. PlanetPress Design uses a lossy compression (JPEG compression) for
photo quality images. A lossy compression does not preserve all image information. In the case of photo
quality, you set a compression level that determines how much image information is lost. An appropriate
compression level results in no visible deterioration of quality in the document output.
13.6.3 Image Quality Settings
The image quality and compression settings in PlanetPress Design apply only to the images included in the
document. They do not apply to dynamic images that are external to the document. Note however that you
can adjust the image quality of dynamic images external to the document if you use the Image Downloader to
download the images to their runtime location.
You can set a default image quality for all bitmapped image resources you add to the document in the
Document dialog box. You can also adjust the image quality for an individual bitmapped image resource. You
set a single compression level for all photo quality image resources in the document.
Related topics:
Static and Dynamic Images (Page 168)
Supported Image Formats (Page 169)
Image Formats: Bitmapped, Vector, and Metafile Formats (Page 171)
Resolution (Page 172)
Color Depth (Page 192)
Pixel Dimensions (Page 175)
Scanline Orientation (Page 352)
Image Size on the Document Page (Page 179)
PlanetPress Talk Expressions for Dynamic Images that Reference Image Resources (Page 180)
PlanetPress Talk Expressions for Dynamic Images that Reference External Images (Page 181)
Image Name and Pathname Resolution in Dynamic Images (Page 187)
Caches (Page 188)
Guidelines for Optimizing Images (Page 189)
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