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List:       kde-commits
Subject:    extragear/graphics/doc/digikam
From:       Laurent Espitallier <laurent.espitallier () laposte ! net>
Date:       2010-02-28 21:31:26
Message-ID: 1267392686.378959.5375.nullmailer () svn ! kde ! org
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SVN commit 1097304 by lespitallier:

PGF format support (file-formats.docbook)

 M  +6 -0      file-formats.docbook  
 M  +1 -1      index.docbook  


--- trunk/extragear/graphics/doc/digikam/file-formats.docbook #1097303:1097304
@@ -62,6 +62,12 @@
 
             </sect3>
 
+            <sect3>            <title>PGF</title>
+	    <para> "Progressive Graphics File" is another not so known but open file image \
format. Wavelet-based, it allows lossless and lossy data compression. PGF compares \
well with JPEG 2000 but it was developed for speed (compression/decompression) rather \
than to be the best at compression ratio. At the same file size a PGF file looks \
significantly better than a JPEG one, while remaining very good at progressive \
display too. Thus, it should be well-suited to the web.  For more information about \
the PGF format see the <ulink url="http://www.libpgf.org/">PGF homepage</ulink>. +	   \
</para>  +
+            </sect3>
+
             <sect3>            <title>RAW</title>
 
                 <para>
--- trunk/extragear/graphics/doc/digikam/index.docbook #1097303:1097304
@@ -1471,7 +1471,7 @@
 	<para><command>GIF</command> is a proprietary. patented format and slowly \
disappearing from the market. Don't use it.</para>  <para><command>PNG</command> has \
been invented as a Open Source standard to replace GIF, but it does much more. It is \
lossless, supports XMP, EXIF and IPTC metadata, 16 bit color encoding and full \
transparency. PNG can store gamma and chromaticity data for improved color matching \
on heterogeneous platforms. Its drawback are a relatively big footprints (but smaller \
than TIFF) and slow compression. We recommend it.</para>  \
<para><command>TIFF</command> has been widely accepted as an image format. TIFF can \
exist in uncompressed form or in a container using a lossless compression algorithm \
(Deflate). It maintains high image quality but at the expense of much larger file \
sizes. Some cameras let you save your images in this format. The problem is that the \
format has been altered by so many people that there are now 50 or more flavors and \
                not all are recognizable by all applications.</para>
-	<para><command>PGF</command> "Progressive Graphics File" is another not so known \
but open file image format. Wavelet-based it allows lossless and lossy data \
compression. PGF compares well with JPEG 2000 but it was developed for speed \
(compression/decompression) rather than to be the best at compression ratio. At the \
same file size a PGF file looks significantly better than a JPEG one, while remaining \
very good at progressive display too. Thus, it should be well-suited to the \
web.</para>  +	<para><command>PGF</command> "Progressive Graphics File" is another \
not so known but open file image format. Wavelet-based, it allows lossless and lossy \
data compression. PGF compares well with JPEG 2000 but it was developed for speed \
(compression/decompression) rather than to be the best at compression ratio. At the \
same file size a PGF file looks significantly better than a JPEG one, while remaining \
very good at progressive display too. Thus, it should be well-suited to the web. For \
more information about the PGF format see the <ulink url="http://www.libpgf.org/">PGF \
homepage</ulink>.</para>   <para><command>RAW</command> format. Some, typically more \
expensive, cameras support RAW format shooting. The RAW format is not really an image \
standard at all, it is a container format which is different for every brand and \
camera model. RAW format images contain minimally processed data from the image \
sensor of a digital camera or image scanner. Raw image files are sometimes called \
digital negatives, as they fulfill the same role as film negatives in traditional \
chemical photography: that is, the negative is not directly usable as an image, but \
has all of the information needed to create an image. Storing photographs in a \
camera's RAW format provides for higher dynamic range and allows you to alter \
settings, such as white balance, after the photograph has been taken. Most \
professional photographers use RAW format, because it offers them maximum \
flexibility. The downside is that RAW image files can be very large indeed.</para>  \
<para>My recommendation is clearly to <command>abstain from archiving in RAW \
format</command> (as opposed to shooting in RAW format, which I recommend). It has \
all bad ingredients: many varieties and proprietary nature. It is clear that in a few \
years time you cannot use your old RAW files anymore. I have already seen people \
changing camera, losing their color profiles and having great difficulty to treat \
their old RAW files correctly. Better change to DNG format!</para>  \
<para><command>DNG</command> Digital Negative file format is a royalty free and open \
RAW image format designed by Adobe Systems. DNG was a response to demand for a \
unifying camera raw file format. It is based on the TIFF/EP format, and mandates use \
of metadata. A handful of camera manufacturers have adopted DNG already, let's hope \
that the main contenders Canon and Nikon will use it one day.</para>


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