My question about
how can i get best printing quality from pdf format
and if ican compress pdf files - with out reduce printing quality
any way,
BIG THANKING for all above solutions
There are several forms of compression within PDF.
The most obvious is image compression. Within PDF, ZIP compression and JPEG2000 lossless compression totally preserve image quality without any loss of detail or color information. Such compression should be used for any raster images which effectively portray what should have been expressed with text and vector artwork. For photographic imagery, JPEG Maximum Quality (= Minimum Compression) or JPEG2000 Maximum Quality (= Minimum Compression) generally suffices to achieve fairly significant file size compression without any noticeable quality loss. JPEG2000 supposedly had a edge over JPEG in terms of maintaining highest quality. Obviously, one should never subject digital imagery to multiple open-edit-save cycles with any lossy file format. If you use JPEG or JPEG2000 for imagery, it should be only for the final image, not while you work on same (TIFF or PSD would be much more appropriate as digital working image file formats). Note that within Adobe applications, PDF file generation options (.joboptions) offer
JPEG (Automatic) and
JPEG2000 (Automatic) settings for images. With those settings, each image is analyzed during PDF generation. If a particular image is determined to be non-photographic and potentially harmed by JPEG or JPEG2000 compression, it is compressed with either ZIP or JPEG2000 Lossless compression in lieu of JPEG or JPEG2000 lossy compression respectively. Adobe strongly recommends these “automatic” variants of compression options in conjunction with quality set to “maximum.”
The second form of compression that is available within PDF is object stream compression. This became available with PDF 1.5 (Acrobat 6). With object stream compression, all other aspects of the PDF file's object specifications including text and vector objects are internally flate (i.e. ZIP) compressed. This compression is totally lossless.
What do you need to get such compression?
Use of the PDF/X-4 PDF creation options in Adobe applications will automatically get you object stream compression. By default, the image compression settings are
JPEG (Automatic), Maximum Quality for color/grayscale and
CCITT Group 4 (lossless) for bitmaps. These are an excellent starting point and for the vast majority of situations yield the best compromise in terms of high image quality and reasonably high compression. You
might (no guarantee) achieve slightly better results (slightly less lossiness and slightly better compression with color/grayscale image compression set to
JPEG2000 (Automatic), Maximum Quality.
All modern RIPs should be able to accommodate PDF 1.5 as well as PDF/X-4.
- Dov