Photo CD
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Photo CD files combine six different resolution version of the original image into a single compressed file. | Photo CD files combine six different resolution version of the original image into a single compressed file. | ||
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| + | Designed for 35 mm photography, the original Photo CD Master disc can hold about 100 images, or four, 24-exposure rolls of film. The images are stored using the Photo YCC color encoding metric, developed by Kodak, which stores data at multiple levels of resolution in units called IMAGE PAC files.<ref>https://web.archive.org/web/19961227013151/http://www.kodak.com/digitalImaging/aboutPhotoCD/aboutPCD5.shtml</ref> | ||
== Identification == | == Identification == | ||
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* [http://www.kodak.com/go/photocd Kodak Photo CD web page] | * [http://www.kodak.com/go/photocd Kodak Photo CD web page] | ||
* {{EGFF|photocd|Kodak Photo CD File Format Summary}}, from the [[Encyclopedia of Graphics File Formats]] | * {{EGFF|photocd|Kodak Photo CD File Format Summary}}, from the [[Encyclopedia of Graphics File Formats]] | ||
| + | * [https://archive.org/details/mac_Graphics_File_Formats_Second_Edition_1996/page/n543/mode/2up Encyclopedia of Graphics File Formats Chapter on PCD] | ||
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| + | ==References== | ||
| + | <references/> | ||
[[Category:Optical Discs]] | [[Category:Optical Discs]] | ||
Revision as of 19:18, 23 June 2023
Kodak Photo CD (PCD) is an image file format that was used by products and services which developed photographs by digitizing them and writing them to a CD.
Photo CD files combine six different resolution version of the original image into a single compressed file.
Designed for 35 mm photography, the original Photo CD Master disc can hold about 100 images, or four, 24-exposure rolls of film. The images are stored using the Photo YCC color encoding metric, developed by Kodak, which stores data at multiple levels of resolution in units called IMAGE PAC files.[1]
Contents |
Identification
The ASCII string "PCD_IPI" appears in the file, usually(?) at offset 2048.
Converting PCD to other formats
PCD files contain multiple resolutions and have other subtitles that tools must be aware of. This page discusses tool support, and recommends pcdtojpeg over ImageMagick, which had flaws at that time. It seems that later versions of ImageMagick have dealt with the colour blow-out issues.
Note that, when converting PCD files using ImageMagick, you must manually select the resolution layer you want. e.g.
$ convert BlownJohn.pcd[0] BlownJohn-0.png $ convert BlownJohn.pcd[1] BlownJohn-1.png $ convert BlownJohn.pcd[2] BlownJohn-2.png $ convert BlownJohn.pcd[3] BlownJohn-3.png $ convert BlownJohn.pcd[4] BlownJohn-4.png $ convert BlownJohn.pcd[5] BlownJohn-5.png $ convert BlownJohn.pcd[6] BlownJohn-6.png $ convert BlownJohn.pcd[7] BlownJohn-7.png $ convert BlownJohn.pcd[8] BlownJohn-8.png
However, examining the results, we can see that some of these are the same:
$ ls -l BlownJohn-?.png
52322 BlownJohn-0.png
52322 BlownJohn-1.png
191840 BlownJohn-2.png
707221 BlownJohn-3.png
2476659 BlownJohn-4.png
9668328 BlownJohn-5.png
28572165 BlownJohn-6.png
28572165 BlownJohn-7.png
28572165 BlownJohn-8.png
i.e. (0,1) are identical, as are (6,7,8), with (1) being the lowest resolution and (6) being the highest. This is consistent with the six resolutions that should be present in the PCD. For the highest resolution, use this:
$ convert BlownJohn.pcd[6] BlownJohn.png
The pcd2html tool may also be useful.
Sample files
- http://cd.textfiles.com/prettywomen/IMAGES/
- http://www.fileformat.info/format/photocd/sample/index.htm (file uses a PICT wrapper)
- Kodak PhotoCD Sampler Disc Image
Software
External Links
- Wikipedia article
- Kodak Photo CD web page
- Kodak Photo CD File Format Summary, from the Encyclopedia of Graphics File Formats
- Encyclopedia of Graphics File Formats Chapter on PCD
