<s>
PDF/A	B-General_Concept
is	O
an	O
ISO-standardized	O
version	O
of	O
the	O
Portable	B-Application
Document	I-Application
Format	I-Application
(	O
PDF	B-Application
)	O
specialized	O
for	O
use	O
in	O
the	O
archiving	B-Application
and	O
long-term	O
preservation	O
of	O
electronic	B-Protocol
documents	I-Protocol
.	O
</s>
<s>
PDF/A	B-General_Concept
differs	O
from	O
PDF	B-Application
by	O
prohibiting	O
features	O
unsuitable	O
for	O
long-term	O
archiving	B-Application
,	O
such	O
as	O
font	O
linking	O
(	O
as	O
opposed	O
to	O
font	O
embedding	O
)	O
and	O
encryption	O
.	O
</s>
<s>
The	O
ISO	O
requirements	O
for	O
PDF/A	B-General_Concept
file	B-Application
viewers	I-Application
include	O
color	O
management	O
guidelines	O
,	O
support	O
for	O
embedded	O
fonts	O
,	O
and	O
a	O
user	O
interface	O
for	O
reading	O
embedded	O
annotations	O
.	O
</s>
<s>
+	O
ISO	B-General_Concept
19005	I-General_Concept
–	O
Document	O
management	O
–	O
Electronic	B-Protocol
document	I-Protocol
file	O
format	O
for	O
long-term	O
preservation	O
(	O
PDF/A	B-General_Concept
)	O
Subtitle	O
Published	O
Standard	O
Based	O
on	O
Ref	O
.	O
</s>
<s>
PDF	B-Application
is	O
a	O
standard	O
for	O
encoding	O
documents	O
in	O
an	O
"	O
as	O
printed	O
"	O
form	O
that	O
is	O
portable	O
between	O
systems	O
.	O
</s>
<s>
However	O
,	O
the	O
suitability	O
of	O
a	O
PDF	B-Application
file	I-Application
for	O
archival	O
preservation	O
depends	O
on	O
options	O
chosen	O
when	O
the	O
PDF	B-Application
is	O
created	O
:	O
most	O
notably	O
,	O
whether	O
to	O
embed	O
the	O
necessary	O
fonts	O
for	O
rendering	O
the	O
document	O
;	O
whether	O
to	O
use	O
encryption	O
;	O
and	O
whether	O
to	O
preserve	O
additional	O
information	O
from	O
the	O
original	O
document	O
beyond	O
what	O
is	O
needed	O
to	O
print	O
it	O
.	O
</s>
<s>
PDF/A	B-General_Concept
was	O
originally	O
a	O
new	O
joint	O
activity	O
between	O
the	O
Association	O
for	O
Suppliers	O
of	O
Printing	O
,	O
Publishing	O
and	O
Converting	O
Technologies	O
(	O
NPES	O
)	O
and	O
the	O
Association	O
for	O
Information	O
and	O
Image	O
Management	O
AIIM	O
in	O
conjunction	O
with	O
Adobe	O
to	O
develop	O
an	O
international	O
standard	O
defining	O
the	O
use	O
of	O
the	O
Portable	B-Application
Document	I-Application
Format	I-Application
(	O
PDF	B-Application
)	O
for	O
archiving	B-Application
documents	O
.	O
</s>
<s>
The	O
goal	O
was	O
to	O
address	O
the	O
growing	O
need	O
to	O
electronically	O
archive	B-Application
documents	O
in	O
a	O
way	O
that	O
would	O
ensure	O
preservation	O
of	O
their	O
contents	O
over	O
an	O
extended	O
period	O
of	O
time	O
and	O
ensure	O
that	O
those	O
documents	O
would	O
be	O
able	O
to	O
be	O
retrieved	O
and	O
rendered	O
with	O
a	O
consistent	O
and	O
predictable	O
result	O
in	O
the	O
future	O
.	O
</s>
<s>
The	O
PDF/A	B-General_Concept
standard	O
does	O
not	O
define	O
an	O
archiving	B-Application
strategy	O
or	O
the	O
goals	O
of	O
an	O
archiving	B-Application
system	O
.	O
</s>
<s>
It	O
identifies	O
a	O
"	O
profile	O
"	O
for	O
electronic	B-Protocol
documents	I-Protocol
that	O
ensures	O
the	O
documents	O
can	O
be	O
reproduced	O
exactly	O
the	O
same	O
way	O
using	O
various	O
software	O
in	O
years	O
to	O
come	O
.	O
</s>
<s>
A	O
key	O
element	O
to	O
this	O
reproducibility	O
is	O
the	O
requirement	O
for	O
PDF/A	B-General_Concept
documents	O
to	O
be	O
100%	O
self-contained	O
.	O
</s>
<s>
A	O
PDF/A	B-General_Concept
document	O
is	O
not	O
permitted	O
to	O
be	O
reliant	O
on	O
information	O
from	O
external	O
sources	O
(	O
e.g.	O
,	O
font	O
programs	O
and	O
data	O
streams	O
)	O
,	O
but	O
may	O
include	O
annotations	O
(	O
e.g.	O
,	O
hypertext	O
links	O
)	O
that	O
link	O
to	O
external	O
documents	O
.	O
</s>
<s>
Other	O
key	O
elements	O
to	O
PDF/A	B-General_Concept
conformance	O
include	O
:	O
</s>
<s>
JavaScript	B-Language
and	O
executable	O
file	O
launches	O
are	O
forbidden	O
.	O
</s>
<s>
This	O
also	O
applies	O
to	O
the	O
so-called	O
PostScript	B-Language
standard	O
fonts	O
such	O
as	O
Times	O
or	O
Helvetica	O
.	O
</s>
<s>
LZW	B-Algorithm
is	O
forbidden	O
due	O
to	O
intellectual	O
property	O
constraints	O
.	O
</s>
<s>
JPEG	O
2000	O
image	O
compression	O
models	O
are	O
not	O
allowed	O
in	O
PDF/A	B-General_Concept
-1	O
(	O
based	O
on	O
PDF	B-Application
1.4	O
)	O
,	O
as	O
it	O
was	O
first	O
introduced	O
in	O
PDF	B-Application
1.5	O
.	O
</s>
<s>
JPEG	O
2000	O
compression	O
is	O
allowed	O
in	O
PDF/A	B-General_Concept
-2	O
and	O
PDF/A	B-General_Concept
-3	O
.	O
</s>
<s>
Transparent	O
objects	O
and	O
layers	O
(	O
Optional	O
Content	O
Groups	O
)	O
are	O
forbidden	O
in	O
PDF/A	B-General_Concept
-1	O
but	O
are	O
allowed	O
in	O
PDF/A	B-General_Concept
-2	O
.	O
</s>
<s>
Provisions	O
for	O
digital	O
signatures	O
in	O
accordance	O
with	O
the	O
PAdES	O
(	O
PDF	B-Application
advanced	O
electronic	O
signatures	O
)	O
standard	O
are	O
supported	O
in	O
PDF/A	B-General_Concept
-2	O
.	O
</s>
<s>
Embedded	O
files	O
are	O
forbidden	O
in	O
PDF/A	B-General_Concept
-1	O
,	O
but	O
PDF/A	B-General_Concept
-2	O
allows	O
embedding	O
of	O
PDF/A	B-General_Concept
files	O
,	O
facilitating	O
the	O
archiving	B-Application
of	O
sets	O
of	O
PDF/A	B-General_Concept
documents	O
in	O
a	O
single	O
file	O
.	O
</s>
<s>
PDF/A	B-General_Concept
-3	O
allows	O
embedding	O
of	O
any	O
file	O
format	O
such	O
as	O
XML	O
,	O
CAD	O
and	O
others	O
into	O
PDF/A	B-General_Concept
documents	O
.	O
</s>
<s>
The	O
use	O
of	O
XML-based	O
XML	B-Language
Forms	I-Language
Architecture	I-Language
(	O
XFA	B-Language
)	O
forms	O
is	O
forbidden	O
in	O
PDF/A	B-General_Concept
.	O
</s>
<s>
(	O
XFA	B-Language
form	O
data	O
may	O
be	O
preserved	O
in	O
a	O
PDF/A	B-General_Concept
-2	O
file	O
by	O
moving	O
from	O
XFA	B-Language
key	O
to	O
the	O
Names	O
tree	O
that	O
itself	O
is	O
the	O
value	O
of	O
the	O
XFAResources	O
key	O
of	O
the	O
Names	O
dictionary	O
of	O
the	O
document	O
catalog	O
dictionary	O
.	O
)	O
</s>
<s>
Interactive	O
PDF	B-Application
form	O
fields	O
must	O
have	O
an	O
appearance	O
dictionary	O
associated	O
with	O
the	O
field	O
's	O
data	O
.	O
</s>
<s>
Part	O
1	O
of	O
the	O
standard	O
was	O
first	O
published	O
on	O
September	O
28	O
,	O
2005	O
,	O
and	O
specifies	O
two	O
levels	O
of	O
conformance	O
for	O
PDF	B-Application
files	I-Application
:	O
</s>
<s>
A	O
later	O
standard	O
,	O
PDF/UA	B-Protocol
,	O
was	O
developed	O
to	O
eliminate	O
what	O
became	O
considered	O
some	O
of	O
PDF/A	B-General_Concept
'	O
s	O
shortcomings	O
,	O
replacing	O
many	O
of	O
its	O
general	O
guidelines	O
with	O
more	O
detailed	O
technical	O
specifications	O
.	O
</s>
<s>
Part	O
2	O
of	O
the	O
standard	O
,	O
published	O
on	O
June	O
20	O
,	O
2011	O
,	O
addresses	O
some	O
of	O
the	O
new	O
features	O
added	O
with	O
versions	O
1.5	O
,	O
1.6	O
and	O
1.7	O
of	O
the	O
PDF	B-Application
Reference	O
.	O
</s>
<s>
PDF/A	B-General_Concept
-1	O
files	O
will	O
not	O
necessarily	O
conform	O
to	O
PDF/A	B-General_Concept
-2	O
,	O
and	O
PDF/A	B-General_Concept
-2	O
compliant	O
files	O
will	O
not	O
necessarily	O
conform	O
to	O
PDF/A	B-General_Concept
-1	O
.	O
</s>
<s>
Part	O
2	O
of	O
the	O
PDF/A	B-General_Concept
Standard	O
is	O
based	O
on	O
a	O
PDF	B-Application
1.7	O
(	O
ISO	B-Application
32000-1	I-Application
)	O
,	O
rather	O
than	O
PDF	B-Application
1.4	O
and	O
offers	O
several	O
new	O
features	O
:	O
</s>
<s>
provisions	O
for	O
digital	O
signatures	O
in	O
accordance	O
with	O
the	O
PDF	B-Application
Advanced	O
Electronic	O
Signatures	O
–	O
PAdES	O
standard	O
.	O
</s>
<s>
the	O
option	O
of	O
embedding	O
PDF/A	B-General_Concept
files	O
to	O
facilitate	O
archiving	B-Application
of	O
sets	O
of	O
documents	O
with	O
a	O
single	O
file	O
.	O
</s>
<s>
PDF/A	B-General_Concept
-2a	O
and	O
PDF/A	B-General_Concept
-2b	O
correspond	O
to	O
conformance	O
levels	O
a	O
and	O
b	O
in	O
PDF/A	B-General_Concept
-1	O
.	O
</s>
<s>
A	O
new	O
conformance	O
level	O
,	O
PDF/A	B-General_Concept
-2u	O
,	O
represents	O
Level	O
B	O
conformance	O
(	O
PDF/A	B-General_Concept
-2b	O
)	O
with	O
the	O
additional	O
requirement	O
that	O
all	O
text	O
in	O
the	O
document	O
have	O
Unicode	O
mapping	O
.	O
</s>
<s>
Part	O
3	O
of	O
the	O
standard	O
,	O
published	O
on	O
October	O
15	O
,	O
2012	O
,	O
differs	O
from	O
PDF/A	B-General_Concept
-2	O
in	O
only	O
one	O
regard	O
:	O
it	O
allows	O
embedding	O
of	O
arbitrary	O
file	O
formats	O
(	O
such	O
as	O
XML	O
,	O
CSV	O
,	O
CAD	O
,	O
word-processing	O
documents	O
,	O
spreadsheet	O
documents	O
,	O
and	O
others	O
)	O
into	O
PDF/A	B-General_Concept
conforming	O
documents	O
.	O
</s>
<s>
Part	O
4	O
of	O
the	O
standard	O
,	O
based	O
on	O
PDF	B-Application
2.0	O
,	O
was	O
published	O
in	O
late	O
2020	O
.	O
</s>
<s>
Archives	O
sometimes	O
request	O
from	O
their	O
users	O
to	O
submit	O
PDF/A	B-General_Concept
Files	O
.	O
</s>
<s>
They	O
thus	O
provide	O
their	O
users	O
with	O
information	O
how	O
to	O
convert	O
their	O
files	O
to	O
PDF/A	B-General_Concept
.	O
</s>
<s>
When	O
documents	O
are	O
converted	O
to	O
PDF/A	B-General_Concept
visual	O
inspection	O
is	O
needed	O
since	O
errors	O
in	O
the	O
visual	O
content	O
are	O
common	O
.	O
</s>
<s>
In	O
a	O
test	O
sample	O
11	O
percent	O
of	O
the	O
produced	O
PDF/A	B-General_Concept
-1b	O
document	O
contained	O
visual	O
artefacts	O
.	O
</s>
<s>
Archives	O
thus	O
usually	O
do	O
not	O
convert	O
to	O
PDF/A	B-General_Concept
themselves	O
.	O
</s>
<s>
Instead	O
,	O
some	O
archives	O
ask	O
their	O
users	O
to	O
provide	O
a	O
PDF/A	B-General_Concept
document	O
.	O
</s>
<s>
Typical	O
computer	O
setups	O
provide	O
several	O
methods	O
for	O
the	O
conversion	O
of	O
documents	O
to	O
PDF/A	B-General_Concept
with	O
different	O
pros	O
and	O
cons	O
.	O
</s>
<s>
Converting	O
a	O
simple	O
PDF	B-Application
(	O
up	O
to	O
version	O
1.4	O
)	O
into	O
a	O
PDF/A	B-General_Concept
-2	O
usually	O
works	O
as	O
expected	O
,	O
except	O
for	O
problems	O
with	O
glyphs	B-Application
.	O
</s>
<s>
According	O
to	O
the	O
PDF	B-Application
Association	O
,	O
"	O
Problems	O
can	O
occur	O
before	O
and/or	O
during	O
the	O
generation	O
of	O
PDFs	B-Application
.	O
</s>
<s>
A	O
PDF/A	B-General_Concept
file	O
can	O
be	O
formally	O
correct	O
yet	O
still	O
have	O
incorrect	O
glyphs	B-Application
.	O
</s>
<s>
In	O
PDF/A	B-General_Concept
,	O
text/font	O
usage	O
is	O
specified	O
uniquely	O
enough	O
to	O
ensure	O
that	O
it	O
cannot	O
be	O
incorrect	O
.	O
</s>
<s>
If	O
viewers	O
or	O
printers	O
do	O
not	O
offer	O
complete	O
support	O
for	O
encoding	O
systems	O
,	O
this	O
can	O
result	O
in	O
problems	O
with	O
regard	O
to	O
PDF/A.	O
"	O
</s>
<s>
A	O
document	O
produced	O
with	O
optical	B-Application
character	I-Application
recognition	I-Application
(	O
OCR	O
)	O
conversion	O
into	O
PDF/A	B-General_Concept
-2	O
or	O
PDF/A	B-General_Concept
-3	O
does	O
n't	O
support	O
the	O
notdefglyph	O
flag	O
.	O
</s>
<s>
PDF/A	B-General_Concept
standard	O
documents	O
can	O
be	O
created	O
with	O
the	O
following	O
software	O
:	O
SoftMaker	B-Application
Office	I-Application
2021	I-Application
,	O
MS	O
Word	O
2010	O
and	O
newer	O
,	O
Adobe	O
Acrobat	O
Distiller	O
,	O
PDF	B-Application
Creator	O
,	O
OpenOffice	O
or	O
LibreOffice	B-Application
since	O
release	O
3.0	O
,	O
LaTeX	O
with	O
pdfx	O
or	O
pdfTeX	O
addons	O
,	O
or	O
by	O
using	O
a	O
virtual	O
PDF	B-Application
printer	O
(	O
Adobe	O
Acrobat	O
Pro	O
,	O
PDF24	O
,	O
FreePDF	O
+	O
Ghostscript	O
)	O
.	O
</s>
<s>
A	O
PDF/A	B-General_Concept
document	O
can	O
be	O
identified	O
as	O
such	O
through	O
PDF/A	B-General_Concept
-specific	O
metadata	O
located	O
in	O
the	O
"	O
http://www.aiim.org/pdfa/ns/id/	O
"	O
namespace	O
.	O
</s>
<s>
a	O
PDF	B-Application
document	O
can	O
be	O
PDF/A	B-General_Concept
-compliant	O
,	O
except	O
for	O
its	O
lack	O
of	O
PDF/A	B-General_Concept
metadata	O
.	O
</s>
<s>
This	O
may	O
happen	O
for	O
instance	O
with	O
documents	O
that	O
were	O
generated	O
before	O
the	O
definition	O
of	O
the	O
PDF/A	B-General_Concept
standard	O
,	O
by	O
authors	O
aware	O
of	O
features	O
that	O
present	O
long-term	O
preservation	O
issues	O
.	O
</s>
<s>
a	O
PDF	B-Application
document	O
can	O
be	O
identified	O
as	O
PDF/A	B-General_Concept
,	O
but	O
may	O
incorrectly	O
contain	O
PDF	B-Application
features	O
not	O
allowed	O
in	O
PDF/A	B-General_Concept
;	O
hence	O
,	O
documents	O
which	O
claim	O
to	O
be	O
PDF/A	B-General_Concept
-compliant	O
should	O
be	O
tested	O
for	O
PDF/A	B-General_Concept
compliance	O
.	O
</s>
<s>
Validation	O
of	O
PDF/A	B-General_Concept
documents	O
is	O
attempted	O
to	O
reveal	O
whether	O
a	O
produced	O
file	O
really	O
is	O
a	O
PDF/A	B-General_Concept
file	O
or	O
not	O
.	O
</s>
<s>
Unfortunately	O
,	O
PDF/A	B-General_Concept
validators	O
quite	O
often	O
disagree	O
,	O
since	O
the	O
interpretation	O
of	O
the	O
PDF/A	B-General_Concept
standards	O
is	O
not	O
always	O
clear	O
.	O
</s>
<s>
Industry	O
collaboration	O
in	O
the	O
original	O
PDF/A	B-General_Concept
Competence	O
Center	O
led	O
to	O
the	O
development	O
of	O
the	O
Isartor	O
Test	O
Suite	O
in	O
2007	O
and	O
2008	O
.	O
</s>
<s>
The	O
test	O
suite	O
consists	O
of	O
204	O
PDF	B-Application
files	I-Application
intentionally	O
constructed	O
to	O
systematically	O
fail	O
each	O
of	O
the	O
requirements	O
for	O
PDF/A	B-General_Concept
-1b	O
conformance	O
,	O
allowing	O
developers	O
to	O
test	O
the	O
ability	O
of	O
their	O
software	O
to	O
validate	O
against	O
the	O
standard	O
's	O
most	O
basic	O
level	O
of	O
conformance	O
.	O
</s>
<s>
By	O
mid-2009	O
the	O
test	O
suite	O
had	O
already	O
made	O
an	O
appreciable	O
difference	O
in	O
the	O
general	O
quality	O
of	O
PDF/A	B-General_Concept
validation	O
software	O
.	O
</s>
<s>
The	O
veraPDF	O
consortium	O
,	O
led	O
by	O
the	O
Open	O
Preservation	O
Foundation	O
and	O
the	O
PDF	B-Application
Association	O
,	O
was	O
created	O
in	O
response	O
to	O
the	O
EU	O
Commission	O
's	O
PREFORMA	O
challenge	O
to	O
develop	O
an	O
open-source	O
validator	O
for	O
the	O
PDF/A	B-General_Concept
format	O
.	O
</s>
<s>
The	O
PDF	B-Application
Association	O
launched	O
the	O
PDF	B-Application
Validation	O
Technical	O
Working	O
Group	O
in	O
November	O
2014	O
to	O
articulate	O
a	O
plan	O
for	O
developing	O
an	O
industry-supported	O
PDF/A	B-General_Concept
validator	O
.	O
</s>
<s>
The	O
Phase	O
3	O
testing	O
and	O
acceptance	O
period	O
concluded	O
in	O
July	O
,	O
2017	O
.	O
veraPDF	O
now	O
covers	O
all	O
parts	O
(	O
1	O
,	O
2	O
and	O
3	O
)	O
and	O
conformance	O
levels	O
(	O
a	O
,	O
b	O
,	O
u	O
)	O
of	O
PDF/A	B-General_Concept
.	O
</s>
<s>
veraPDF	O
is	O
available	O
for	O
installation	O
on	O
Windows	O
,	O
macOS	O
,	O
or	O
Linux	O
using	O
a	O
PDFBox-based	O
or	O
"	O
Greenfields	O
"	O
PDF	B-Application
parser	O
.	O
</s>
<s>
ignore	O
any	O
data	O
that	O
are	O
not	O
described	O
by	O
the	O
PDF	B-Application
and	O
PDF/A	B-General_Concept
standards	O
;	O
</s>
<s>
When	O
encountering	O
a	O
file	O
that	O
claims	O
conformance	O
with	O
PDF/A	B-General_Concept
,	O
some	O
PDF	B-Application
viewers	O
will	O
default	O
to	O
a	O
special	O
"	O
PDF/A	B-General_Concept
viewing	O
mode	O
"	O
to	O
fulfill	O
conforming	O
reader	O
requirements	O
.	O
</s>
<s>
To	O
take	O
one	O
example	O
,	O
Adobe	O
Acrobat	O
and	O
Adobe	O
Reader	O
9	O
include	O
an	O
alert	O
to	O
advise	O
the	O
user	O
that	O
PDF/A	B-General_Concept
viewing	O
mode	O
has	O
been	O
activated	O
.	O
</s>
<s>
Some	O
PDF	B-Application
viewers	O
allow	O
users	O
to	O
disable	O
the	O
PDF/A	B-General_Concept
viewing	O
mode	O
or	O
to	O
remove	O
the	O
PDF/A	B-General_Concept
information	O
from	O
a	O
file	O
.	O
</s>
<s>
A	O
PDF/A	B-General_Concept
document	O
must	O
embed	O
all	O
fonts	O
in	O
use	O
;	O
accordingly	O
,	O
a	O
PDF/A	B-General_Concept
file	O
will	O
often	O
be	O
larger	O
than	O
an	O
equivalent	O
PDF	B-Application
file	I-Application
that	O
does	O
not	O
include	O
embedded	O
fonts	O
.	O
</s>
<s>
The	O
use	O
of	O
transparency	O
is	O
forbidden	O
in	O
PDF/A	B-General_Concept
-1	O
.	O
</s>
<s>
The	O
majority	O
of	O
PDF	B-Application
generation	O
tools	O
that	O
allow	O
for	O
PDF/A	B-General_Concept
document	O
compliance	O
,	O
such	O
as	O
the	O
PDF	B-Application
export	O
in	O
OpenOffice.org	O
or	O
PDF	B-Application
export	O
tool	O
in	O
Microsoft	O
Office	O
2007	O
suites	O
,	O
will	O
also	O
make	O
any	O
transparent	O
images	O
in	O
a	O
given	O
document	O
non-transparent	O
.	O
</s>
<s>
That	O
restriction	O
was	O
removed	O
in	O
PDF/A	B-General_Concept
-2	O
.	O
</s>
<s>
Some	O
archivists	O
have	O
voiced	O
concerns	O
that	O
PDF/A	B-General_Concept
-3	O
,	O
which	O
allows	O
arbitrary	O
files	O
to	O
be	O
embedded	O
in	O
PDF/A	B-General_Concept
documents	O
,	O
could	O
result	O
in	O
circumvention	O
of	O
memory	O
institution	O
procedures	O
and	O
restrictions	O
on	O
archived	O
formats	O
.	O
</s>
<s>
The	O
PDF	B-Application
Association	O
had	O
addressed	O
various	O
misconceptions	O
regarding	O
PDF/A	B-General_Concept
in	O
its	O
publication	O
"	O
PDF/A	B-General_Concept
in	O
a	O
Nutshell	O
2.0	O
"	O
.	O
</s>
