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.
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 BlownJohn-0.png $ convert BlownJohn.pcd BlownJohn-1.png $ convert BlownJohn.pcd BlownJohn-2.png $ convert BlownJohn.pcd BlownJohn-3.png $ convert BlownJohn.pcd BlownJohn-4.png $ convert BlownJohn.pcd BlownJohn-5.png $ convert BlownJohn.pcd BlownJohn-6.png $ convert BlownJohn.pcd BlownJohn-7.png $ convert BlownJohn.pcd 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 BlownJohn.png
The pcd2html tool may also be useful.