From kde-commits Sun Feb 28 23:05:30 2010 From: Laurent Espitallier Date: Sun, 28 Feb 2010 23:05:30 +0000 To: kde-commits Subject: extragear/graphics/doc/digikam Message-Id: <1267398330.618265.16660.nullmailer () svn ! kde ! org> X-MARC-Message: https://marc.info/?l=kde-commits&m=126745017429328 SVN commit 1097343 by lespitallier: PGF format support (minor corrections) M +2 -1 file-formats.docbook M +1 -1 index.docbook --- trunk/extragear/graphics/doc/digikam/file-formats.docbook #1097342:1097343 @@ -63,7 +63,8 @@ PGF - "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 PGF homepage. + + "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 but at the moment few browsers can display it. For more information about the PGF format see the libPGF homepage. --- trunk/extragear/graphics/doc/digikam/index.docbook #1097342:1097343 @@ -1471,7 +1471,7 @@ GIF is a proprietary. patented format and slowly disappearing from the market. Don't use it. PNG 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. TIFF 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. - PGF "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 PGF homepage. + PGF "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 but at the moment few browsers can display it. For more information about the PGF format see the libPGF homepage. RAW 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. My recommendation is clearly to abstain from archiving in RAW format (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! DNG 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.