I have noticed that my TIFF files balloon in size whenever I save them. For instance, a particular file may be 185MB when open with layers in CS6, but it increases to 317MB when I save it as a TIFF. If I use ZIP compression, it may be reduced to 285MB. Is this normal behaviour?
I think this may be the same thing that I noticed on my own files a while back and wondered as you do, what was causing the ballooning file size problem.
The solution I found was to make sure that you have all the layers flattened to a 'Background
' layer at the end of your processing and before you commit to a file save. Just merging layers down or using the short cut keys Ctrl+E or Ctrl+Shift+E etc, does indeed appear to flatten the layers into a single layer, but it does not flatten them into a 'Background
' layer and there is a huge size difference as a result if you don't do this.
Why a 'Background
' layer should be so much smaller than a flattened single layer I do not know (and perhaps someone here does and would like to tell us?), as it contains no more or no less information, but it just does.
Or if you want to save your files with the layers still in tact, then just make sure that the bottom layer of your stack is a 'Background
' layer. You can do this by highlighting the bottom layer of the stack, then selecting the 'layers' menu and 'New Background from Layer' through the layers menu drop down list.