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December 1994
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1994.12.15 14:24 "Re: TIFF File Naming Conventions/Standards?", by Bill Davis
]Ever try to view multiple single page images that should viewed as one
]document? It can be impossible without the creator application or without
]opening each images individually. (Not cool!)
>From an Object Oriented standpoint, a set of multiple single images
should be a single entity. If we consider other file formats, the
Postscript format comes immediately to mind. In Postscript, an
entire document can be collected into a single file.
The problem with multiple images for TIFF is that the format
was designed for a single image. The name says it all: the I
stands for Image instead of document, image group, etc.
When there are multiple images in a single file, the standard
is clear that they are variations of a single image. Only
the first one must be read by a compliant TIFF reader.
I would rather see an extension to the TIFF standard which
allows either:
1) flagging of subsequent IFD's to indicate if they are to
be considered alternate images or additional images (e.g.
by adding an image number, so you can have 3 versions of
the first image and 2 versions of the second image, etc.)
2) a TIFF collection which is a file with a new type which
has an IFD containing references to embedded TIFF files
(e.g. a TIFF definition for an archive file which could
define a TIFF level N compliant reader).
Having a convention for the use of names in various operating
systems is nice, but the same convention can be used to have
a group of GIF files or a group of text files. Putting something
like that in a library causes so many OS dependencies that the
extension and maintenance of the TIFF specific parts of the
library would inevitably suffer.
Does anyone know if the group that determines TIFF standards
has considered this issue? Is this something that the standard
may address in the future or is it considered permanently out
of the scope of the standard?
Bill Davis
wdavis@dw3f.ess.harris.com