ATTACHMENT 5

TIFF IMAGE FILE HEADER INFORMATION

The Library requires that "typical" or "expected" data be provided for most TIFF tags (normally, the data supplied by software default settings). The tags the Library has been using are listed below. Exceptions or options that may not conform to "typical" or default data are noted in the comments column.

Description Tag Comments
NewSubfileType
ImageWidth
ImageLength
BitsPerSample
Compression
PhotometricInterpretation
StripOffsets
SamplesPerPixel
RowsPerStrip
StripByteCounts
DocumentName

Artist
DateTime

254
256
257
258
259
262
273
277
278
279
269

315
306


actual pixel count
actual pixel count







pathname (directory name and file name)
as used for delivery of image
Library of Congress
date and time scanned

5.1

TIFF header: tags 282, 283, and 296

The Library has used varying approaches for the 282, 283, and 296 tags. For a large number of grayscale digital images that reproduce photographs, the following tags were used:

XResolution
YResolution
ResolutionUnit
282
283
296
actual pixel count
actual pixel count
1 (no unit specified)

In previous contracts for printed matter scanned directly from paper, the following values appeared in these same tags:

XResolution
YResolution
ResolutionUnit
282
283
296
scanning resolution
scanning resolution
2

In other cases, the Library has received TIFF images for which no values have been supplied for these tags.

It is possible that certain printing anomalies (like "postage stamp" printing are due to the specific values placed in these TIFF header tags.

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