Library of Congress picture collection

[Varese2002]

The LC has silently introduced new advanced technology to scan their picture collection. Till now downloadable pictures were made available as a JPEG file and as a TIFF file. The TIFF file is (was) described as uncompressed and for archival purposes. The TIFF file was way bigger than the JPEG file, mostly in the region of 20 till 22 megabytes.

Now they have upped this scan with a Highest Resolution TIFF Version, where the file is 150 megabytes. They have probably rescanned a few of their immense stock to try this exactness of snanning.

For an example look here. Has anyone information what the LC is aiming it. Their super 150 MB scans are by the way very beautiful and detailed.

Cheers

Kees

[Ricardo Reis]

I wonder why they don't transition to png...

[Varese2002]

Originally Posted by Ricardo Reis

I wonder why they don't transition to png...

The Library of Congress has made studies about the format for pictures / movies and decided years ago for TIFF as the archival format.

Lately studies have been done by the LC in collaboration with Xerox on the (new) format JPEG 2000. There is a news item on the LC site here.
JPEG 2000 can deliver the same quality in about 50% of the space, which makes it very much more cost effective.

The Dutch National Library has already decided to migrate to JPEG 2000 for their vast 40 million pages project of scanned old newspapers.

You can read about the specification of the JPEG 2000 format in Wikipedia pages.

Cheers

Kees

[Varese2002]

Here is some comparison between PNG and JPEG 2000 (also called JP2), from here

Comparison with PNG

Although JPEG 2000 format supports lossless encoding, it is not intended to completely supersede today's dominant lossless image file formats.
The PNG (Portable Network Graphics) format is still more space-efficient in the case of images with many pixels of the same color, and supports special compression features that JPEG 2000 does not.
It can be expected that PNG will be more heavily used for compressing diagram-type images and JPEG 2000 for photograph-type images, assuming no further changes to either standard.

Cheers

Kees