Turn a Photo CD into a Contact Sheet with pcdovtoppm

pcdovtoppm reads a Kodak Photo CD's overview file and writes one PPM image holding thumbnails of every photo on the disc, ready to convert or archive. Budget about fifteen minutes once the disc is mounted and you know where its overview.pcd lives. Examples here use Netpbm 11.5.2 from the installed netpbm package.

You need a readable overview file and the Netpbm tools. Every command below reads the disc and writes a new image; none of them touch the Photo CD itself. No elevated privileges are normally needed. Reach for sudo only if your account genuinely cannot read the mounted disc or write the output directory.

1. Check the installed command

Confirm which executable will actually run, and read its local option spelling. This is entirely read-only:

$ command -v pcdovtoppm
/usr/bin/pcdovtoppm
$ pcdovtoppm -help
/usr/bin/pcdovtoppm : Unknown option -help

Usage: /usr/bin/pcdovtoppm [-m W] [-s S] [-a A] [-c N|n] [-f F] [-b|-w] <overview.pcd>

The installed program is Netpbm 11.5.2. Its help uses -m for maximum output width, -s for the maximum size of each thumbnail, and -a for the maximum count across. The installed manpage's option text contradicts this with a -w entry for width; trust the executable's own help and synopsis, which say -m, not the page.

2. Locate the overview file

A mounted Photo CD normally exposes its overview file straight away. Swap in your real mount point, then check it's actually readable:

$ PCD_OVERVIEW='/media/PHOTO_CD/overview.pcd'
$ test -r "$PCD_OVERVIEW" && printf '%s\n' 'overview file is readable'
overview file is readable

If that prints nothing, look at the path and mount point without changing anything:

$ ls -l /media/PHOTO_CD/overview.pcd
$ findmnt /media/PHOTO_CD

Keep the path quoted: a mount point with spaces in it has to stay one argument. If the disc isn't mounted, mount it through your desktop or normal system procedure. Mounting sits outside pcdovtoppm entirely and may need administrator access.

3. Create the contact sheet

Redirect the PPM output to a new file. The command writes the image to standard output, so a quiet, apparently uneventful run is exactly what success looks like:

$ pcdovtoppm "$PCD_OVERVIEW" > overview.ppm
$ printf 'exit status: %s\n' "$?"
exit status: 0
$ file overview.ppm
overview.ppm: Netpbm image data, size ..., pixmap

The dimensions depend on the overview file and the options you chose. What actually matters is a zero exit status, a non-empty destination, and a file identification that names a PPM or Netpbm pixmap. Silence is not failure here.

$ pcdovtoppm "$PCD_OVERVIEW" > overview.ppm.new
$ test -s overview.ppm.new && file overview.ppm.new
$ mv overview.ppm.new overview.ppm

That mv is the actual replacement point. If the conversion fails, leave the original alone and remove only the incomplete overview.ppm.new, checked by name. There is no need to touch the source overview file at all.

4. Adjust the layout when you need to

Defaults: maximum width 1152 pixels, maximum thumbnail size 192 pixels, six images across. Set only the constraint that matters to you. This example makes a smaller sheet with eight across:

$ pcdovtoppm -m 768 -s 96 -a 8 "$PCD_OVERVIEW" > overview-compact.ppm
$ file overview-compact.ppm
overview-compact.ppm: Netpbm image data, size ..., pixmap

These are ceilings, not promises that every thumbnail lands at exactly the size you asked for. A large source set can still be limited by whichever of width, image size, or across-count runs out first. If the result is too big, tighten the limits and write to a separate output file so the first result stays around for comparison.

Use -c N to cap the colour count, or -c n for no quantisation, which is the installed help's default. Quantisation shrinks output but can change the colours you see. -b gives the default black background, -w a white one; upstream documentation says the rightmost background flag wins, so keep just one background choice per command.

5. Convert the PPM after checking it

PPM suits Netpbm but gets large fast. If ppmtojpeg is installed, pipe a verified contact sheet straight into it:

$ test -s overview.ppm
$ pcdovtoppm "$PCD_OVERVIEW" | ppmtojpeg > overview.jpg
$ file overview.jpg
overview.jpg: JPEG image data, ...

That's a separate pipeline. A successful JPEG command proves the pipeline ran end to end, not that every thumbnail looks right. Open the JPEG in a viewer and hang on to the PPM until you've actually checked the sheet.

The manual also documents an annotation font via -f FONT, such as -f smallfont.pbm. Only point it at a font file that genuinely exists and is readable; otherwise the default internal font does the job fine. Don't guess a font path copied from another machine.

6. Diagnose failures without touching the disc

A missing or unreadable overview file gives a non-zero exit status. Capture it immediately, before another command overwrites $?:

$ pcdovtoppm "$PCD_OVERVIEW" > overview.ppm.new
$ status=$?
$ printf 'pcdovtoppm status: %s\n' "$status"
pcdovtoppm status: 1

Check the path with ls -l and test -r. If an output file was already created before the failure, treat it as incomplete: do not publish or archive it as finished. Rerun to a fresh temporary name once the input or permissions are fixed.

Do not run the converter as root just to make a permissions error disappear. Fix read access to the mounted source, or write access to your destination directory, through your normal administration process instead. The command cannot repair a disc, mount a volume, or recover missing Photo CD data, and root access won't change that.