TIFF Compression Options

[Puncball]

I was wondering if anyone would be kind enough to elaborate on the pros and cons of saving images in TIFF format and perhaps explain the merits/disadvantages of the different compression options in Photoshop CS3 (None, LZW and Zip)

I have recently processed a 10.7 MB Raw image, which I saved in all three options; first un-cropped (ratio 6 x 4) and then cropped to a ratio of 8 x 10 (No re-sampling).

The sizes of the 6 x 4 and 8 x 10 images, saved as a TIFF files, with the following compressions, were as follows:

6 x 4 No Compression: 56.7 MB
8 x 10 No Compression: 30.7 MB

6 x4 LWZ Compression: 71.0 MB
8 x 10 LWZ Compression: 39.3 MB

6 x4 Zip Compression: 54.9 MB
8 x 10 Zip Compression: 29.7 MB

I am a little confused by the above results, as I expected LWZ Compression to produce smaller files than No Compression

 

[Chappers]

That's strange. Ive just a similar test and the LZW compressed TIFF dropped to about 40% of the original. OK I'm on CS4 but that shouldn't make any difference.

One point about LZW compression. Not all programs can open files compressed this way. It's probably OK on your system but be careful if you send them to someone else.

 

[Puncball]

Interesting; I have just repeated the process with 3 different images (also, without flattening layers) and obtained the same findings: Zip produces the smallest files, followed by No Compression.

Cannot understand this! Must be something wrong with my PC - It would be intersting to hear if others have experianced this

I have also found that Windows Photo Gallery (Vista) does not like TIFF Zip – horizontal streaks across the image

 

[Puncball]

Hi Guys,

I’ve done a little further work on this, and as you can see from below (on my PC), the LZW only appears to work (reduce the size of the file) with the mode in Photoshop CS3 set to 8 Bits/Channel. In all cases where I have it set to 16 Bits/Channel, the LZW Compression increases the size of the files

I would be interested to hear if anyone else gets the same results




Image 2066
8 Bit None 28.8 MB
8 Bit LZW 11.8 MB
16 Bit LZW 70.1 MB
16 Bit None 57.6 MB

Image 2074
8 Bit None 28.8 MB
8 Bit LZW 13.9 MB
16 Bit LZW 72.7 MB
16 Bit None 57.6 MB

Image 2076
8 Bit None 28.8 MB
8 Bit LZW 14.7 MB
16 Bit LZW 73.5 MB
16 Bit None 57.6 MB

 

[Itti]

The compression making things bigger is apparently a bug.