Questions about TIFF-compression

[Peter2]

I don't have a deep understanding of file-formats and compressions and so on, but usually I have the experience with LZW and CCITT:
"Uncompressed TIF has high file size, compression reduces it down to 70-5% file size"

But now I got an uncompressed TIFF (6400 * 4800 pix, 16.400 colors) where I used different "save as tiff .." commands from XNViewMP and got these result:

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original.tif    92'305.350
jpeg.tif         6'142.974
lzw.tif         79'104.426
lzw_pre.tif     55'910.122
packbit.tif     93'066.541
no_compr.tif    92'337.107
zip.tif         66'681.857

The file props of the original are:

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File	
Filename	018.tif	
Filepath	D:\xxx	
Description	TIFF Image file	
File size	88.03 MiB (92’305’350)	
Creation date/time	15.03.2025 - 09:11:21	
Modified date/time	15.03.2025 - 09:11:28	
Accessed date/time	15.03.2025 - 09:36:48	
Rating	0	
Colour Label	0	
File's icon	1	

Image	
Format	TIFF	
Width	6325	
Height	4863	
Dimension	30.7585 Mpixels	
# of bits	24	
Color model	RGB	
DPI	240 x 240	
Print size	66.94x51.47 cm, 26.35x20.26 inches	
Compression	None	
Images/frames count	1	
Origin	Top-Left	

Extra info	
PhotometricInterpretation	 2	
PlanarConfiguration	 1	
SamplesPerPixel	 3	

Color Profile	
Description	sRGB IEC61966-2.1	
Manufacturer	IEC http://www.iec.ch	
Model	IEC 61966-2.1 Default RGB colour space - sRGB	
Copyright	Copyright (c) 1998 Hewlett-Packard Company	

So what's the reason that the compression brings so extreme different results and LZW only a small effect and packbit an increased size?

[cday]

The file size of a TIFF basically depends on:

o The bit depth (1-bit black and white, 8-bit grayscale or colour [only 24-bit and 32-bit colour supported in xnview software] of the image saved;

o Whether the compression option used is lossless or lossy [I think that all options except JPEG compression are lossless] and the alternative save settings options within the compression option selected;

o The complexity of the image content, some compression options being more efficient for particular forms of image [for example, images with large areas of the same colour, such as in a 1-bit depth image white or black areas].

In general, file sizes for colour or grayscale images will be much larger if any option other than JPEG compression is selected.

In general, for 1-bit black and white images Fax [CCITT G4] compression is very efficient, although alternative options may result in smaller file sizes for particular types of images.

Can anyone correct any of those guidelines or add other useful information?

[Peter2]

Hi cday

I always had the idea (the illusion?) that TIFF is lossles. But is it correct that a JPEG compression result in a JPEG, in the package of a TIFF?

[cday]

I always had the idea (the illusion?) that TIFF is lossless. But is it correct that a JPEG compression results in a JPEG, in the package of a TIFF?

A JPEG compression algorithm is used, so in effect yes, whether that matters will depend on the particular use case....

I don't immediately see a situation where saving an image as a TIFF with JPEG compression would have an advantage over saving directly to a JPEG file, which would actually slightly increase the file size, but maybe there are some cases?

Edit: There is also the question of the JPEG save options used, as they are not directly accessible when saving to a TIFF, whether XnView's normal configurable options or fixed settings are used,which might result in a non-optimal image due to quality or larger file size than actually needed?

[Peter2]

Thanks @cday,

and have a fine weekend.

[XnTriq]

TIFF is a flexible, adaptable file format for handling images and data within a single file, by including the header tags (size, definition, image-data arrangement, applied image compression) defining the image's geometry. A TIFF file, for example, can be a container holding JPEG (lossy) and PackBits (lossless) compressed images. A TIFF file also can include a vector-based clipping path (outlines, croppings, image frames). The ability to store image data in a lossless format makes a TIFF file a useful image archive, because, unlike standard JPEG files, a TIFF file using lossless compression (or none) may be edited and re-saved without losing image quality. This is not the case when using the TIFF as a container holding compressed JPEG. Other TIFF options are layers and pages.

Draft DRAFT TIFF Technical Note #2 covers problems with the TIFF 6.0 design for embedding JPEG-compressed data in TIFF, and describes an alternative.

• AWare Systems: TIFF File Format FAQ
• FileFormat.Info: TIFF File Format Summary → JPEG Compression

[XnTriq]

Software for analyzing TIFF files:

• AWare Systems: AsTiffTagViewer
• LibTIFF: TIFF Tools → Windows binaries