Hello trid users,
some days ago my system with Windows 10 updates itself. When checking
the system with ccleaner many file name associations are now broken.
So i look for the reported filename extension. One file name extension
is PDD.
ALL my PDD examples like ORIGINAL.PDD and 0006902.PDD are described by
psd.trid.xml as "Adobe Photoshop image" with file name extension PSD
(See appended output/trid-v-old.txt).
For comparison reason i also run the file format identification
utility DROID ( See
http://sourceforge.net/projects/droid/ ). This
describes the PDD examples as "Adobe Photoshop Image". (see appended
output/file-5.40.txt). It also displays correct mime type
"image/vnd.adobe.photoshop" (see appended output/file-i-5.40.txt).
Some information about the PDD image file format can be found on file
formats archive team web site. This is now expressed by additional
reference URL line like:
RefURL>
http://fileformats.archiveteam.org/wiki/PhotoDeluxe</RefURL>
So i tridscan on about hundreds PDD examples to generate definition
pdd-adobe.trid.xml. Then i manually cleanup the definition. I remove
inside front block section short nil patterns which are probably
triggered by lucky circumstances like :
<Bytes>00</Bytes>
<Pos>46</Pos>
Then i also delete inside global strings section lines which are
probably garbage patterns triggered by accident circumstances like:
<String>)9IYIY</String>
<String>7GWGW</String>
<String>8HXHX</String>
<String>%C4S</String>
<String>3$4C</String>
<String>DTU7</String>
<String>FVFV</String>
<String>JFIF</String>
<String>JZJZ</String>
I also shorten some strings lines like
<String>ADOBE'D</String>
<String>5'''''D''''' ''''PHUT</String>
This now becomes like:
<String>ADOBE</String>
<String>PHUT</String>
Interesting is the last line. According to documentation the image
resources segment of PDD images contain some blocks with a signature
of "PHUT", instead of the usual "8BIM" found in PSD images. So the PDD
file format seems to be an sub format of the Photoshop PSD format. The
PDD format was used by Adobe PhotoDeluxe raster graphics editor. It is
often called Adobe PhotoDeluxe document or image. This software is
discontinued, but it is said the Adobe Photoshop still can open such
images. So to emphasize this fact is i choose another name. that is
expressed by line like:
<FileType>Adobe Photoshop Elements (PhotoDeluxe) image</FileType>
Unfortunately i am too poor to buy an expensive Photoshop software
just to verify that thesis.
So i also check trid definition with some found PSD examples. These
are described by psd.trid.xml as "Adobe Photoshop image" with correct
file name extension PSD (See appended output/trid-v-old.txt), but no
mime type is shown. So according to documentation i update
psd.trid.xml and add that information by additional line like:
<Mime>image/vnd.adobe.photoshop</Mime>
As reference URL the generic Adobe web site was used. Instead maybe
Adobe Photoshop page on Wikipedia with section about file format can
be used, but i choose PSD page on file formats archive team web
site. That reference URL is now used by line like:
<RefURL>
http://fileformats.archiveteam.org/wiki/PSD</RefURL>
Furthermore i add also PDD beside PSD as file name extension and
mention this facts by lines like:
<Ext>PSD/PDD</Ext>
<Rem>PDD is used for PhotoDeluxe variant</Rem>
According to documentation at offset 6 six bytes are declared as
reserved and should be zero. This was true for all my inspected
examples with one exception sample input.psd, which is found in "t"
test sub directory of PerlMagick module of ImageMagick source package
( at least for version 7.0.11-11). Instead nil the bytes are space
characters (0x20). So this example is not recognized by TrID, but by
file command. The command line tools of ImageMagick (See appended
output/identify.txt) and XnView recognize this example as
Adobe Photoshop image by lines like:
nconvert -fullinfo input.psd
identify -verbose input.psd
And the GUI programs of these 2 tools are able to display the flower
image of a red rose.
So example input.psd violates the file formats recommendation, but
this does not seems to hurt the work of many graphic software.
Maybe it is advisable to create a new definition for pure PSD examples
to distinguish PSD from PDD.
But now at the moment with the updated and the variant
pdd-adobe.trid.xml all my inspected examples except for input.psd are
now described (See appended output/trid-v-new.txt).
TrID definition, some examples and output are stored in archive pdd.zip. I hope that
my XML files can be used in future version of triddefs.
With best wishes
Jörg Jenderek
