Today’s Question: I have always used PSD files [Photoshop Document file format] based on your recommendation many years ago when I was first getting into Photoshop and Adobe Camera Raw. In a recent newsletter you said you now use TIFF primarily. Why?
Tim’s Quick Answer: I currently use TIFF files rather than PSD files because both support the same capabilities, and the TIFF files will be smaller in the context of a workflow that revolves around Lightroom Classic.
More Detail: I originally used PSD files for the master version of my images because in early versions of Photoshop the PSD file format supported layers and other features specific to Photoshop, while TIFF files did not. Therefore, PSD files were used for the layered master images, and TIFF files were used for flattened derivative images.
When Photoshop was updated to support layers for TIFF images, I continued to use the same approach of having PSD files be the layered version and TIFF files be the flattened version, mostly just out of habit.
However, with Lightroom Classic you are not able to import Photoshop PSD files unless the Maximize Compatibility option was enabled for the PSD file. The Maximize Compatibility setting causes what is effectively a flattened version of the image to be embedded within the file, causing an increase in file size equal to what a flattened copy of the image would be. For example, if the file contains no layers, the Maximize Compatibility feature would cause the file size to double.
TIFF images do not require a Maximize Compatibility feature to be supported by Lightroom Classic. Therefore, a TIFF file will always be smaller than an equivalent PSD file that is supported by Lightroom Classic.
Note that both PSD and TIFF formats are able to use compression to help reduce the file size. However, even with compression for the PSD file, the Maximize Compatibility feature more than makes up for the reduced file size, causing the file to be larger than an equivalent TIFF file.
Both TIFF and PSD files support saving the same features in Photoshop, so either will work perfectly well. But in the context of Lightroom Classic, the TIFF file will generally be significantly smaller, and therefore is my preferred file format between the two.