TIFF 6.0 Specification
Final—June 3, 1992
32773 = PackBits compression, a simple byte-oriented run-length scheme. See Section 9
for details.
Data compression applies only to the image data, pointed to by StripOffsets.
Default = 1.
Copyright
Copyright notice.
Tag
= 33432 (8298.H)
Type = ASCII
Copyright notice of the person or organization that claims the copyright to the
image. The complete copyright statement should be listed in this field including
any dates and statements of claims. For example, “Copyright, John Smith, 19xx.
All rights reserved.”
DateTime
Date and time of image creation.
Tag
= 306 (132.H)
Type = ASCII
N
= 20
The format is: “YYYY:MM:DD HH:MM:SS”, with hours like those on a 24-hour
clock, and one space character between the date and the time. The length of the
string, including the terminating NUL, is 20 bytes.
ExtraSamples
Description of extra components.
Tag
= 338 (152.H)
Type = SHORT
N
=m
Specifies that each pixel has
m
extra components whose interpretation is defined
by one of the values listed below. When this field is used, the SamplesPerPixel
field has a value greater than the PhotometricInterpretation field suggests.
For example, full-color RGB data normally has SamplesPerPixel=3. If
SamplesPerPixel is greater than 3, then the ExtraSamples field describes the
meaning of the extra samples. If SamplesPerPixel is, say, 5 then ExtraSamples
will contain 2 values, one for each extra sample.
ExtraSamples is typically used to include non-color information, such as opacity,
in an image. The possible values for each item in the field's value are:
0 = Unspecified data
1 = Associated alpha data (with pre-multiplied color)
31