TIFF is the probably the second most common graphics format used today. It may be a long way behind JPEG in popularity, but don’t underestimate its importance in photography and image editing.
TIFF (Tag Image File Format) has one advantage over its JPEG rival: TIFF files are lossless. Data is not discarded each time you make changes and save the file. JPEGs can degrade quite substantially each time you open, edit and save a file: stray colour blocks start to appear in the image (also called artefacts). Until the new JPEG 2000 format becomes more widespread — it has a lossless option — TIFFs will remain essential to anyone wishing to edit or preserve images.
The main drawback with TIFF files is that they are large — sometimes huge. However, as CD burners approach $100 with CD media at around 50 cents, the problem of file size is not as important. If needed, you can compress TIFF files. These smaller files will be quicker to e-mail, plus they take less room on compact storage and flash cards — where space is still an issue.
One way of cutting down a TIFF file size is to use a compression technique known as LZW. This should cut the size almost in half (results will vary depending on the image). To create a TIFF file with LZW compression, you will need to hunt around in the Options menus of your graphics program; it will frequently appear in the File-Save As window. Select the TIFF format, then the Options button. For Photoshop and Elements, the option will appear after you click the Save button. Look for the LZW Compression setting — most programs will keep this as the default until you change it back.
If your image is black and white (greyscale mode) then choose Packbits as the compression option — it will give you around 5-10 per cent better compression than LZW.
Rotate your TIFF files
This is my favourite tip, which I discovered by accident some years ago. It’s a little odd and doesn’t always work, but if you are desperate to squeeze down a file, it may be worth a go. TIFF with LZW compression is less sophisticated than modern formats like JPEG 2000. As a result, it can be a little sloppy when it comes to shrinking a file. The upshot is that it is possible to reduce the size of an image by simply rotating it by 90º.
The difference is far more noticeable when there are large blocks of similar colours — busy pictures with high contrast colours won’t change much. Examples that work well are sunsets or images with significant amounts of sky. It is not a guaranteed result — in some circumstances, the image may actually increase in size! If you are not convinced, try it yourself and then repeat the test with a JPEG.
RGB vs. CMYK
Images stored as CMYK are around 30-40 per cent larger than those in RGB format. A picture in RGB is made up of three channels: red, green and blue. CMYK has four channels: cyan, magenta, yellow and black. This extra channel means that more information must be stored. In practice, most home users won’t need to use CMYK — and most low end graphics programs don’t support it. If size is important, stick to RGB.
This may also answer a nagging problem faced by many users: why can’t certain TIFFs be opened in a graphics programs? The Imaging tool in Windows 9x is notorious for this kind of confusion. The answer is simple — the program doesn’t support TIFF in CMYK formats. In these cases you will see the rather unhelpful error ‘The document cannot be opened. The document’s format is invalid or not supported’. It is more aggravating since Imaging for Windows can usually open TIFFs — but only in RGB format.
Incidentally, JPEGs in CMYK format face the same problem if you try to open them in a Web browser, Imaging for Windows and many other programs. In your Web browser you will see the broken image icon (a small square with a red cross).
Stick with TIFF
Finally, if you are considering TIFF as a file format for an image, you will find its file sizes are smaller and quality is higher if you save the image as a TIFF when it is created. An image that starts as a JPEG will be larger when converted to a TIFF than if it had started life as a TIFF.