Possible to reduce file size of layered Tiffs?

[Guy Burns]

Multi-layered tiffs are approx double the file size of unlayered tiffs because of the stored preview file (if that's what it's called).

Other than turning off the image layer (which does reduce file size but, of course, you lose the preview image entirely), is there any way to stop PS storing the extra image? I'd be happy to see the original image even if it is vastly different from the edited image.

[JohanElzenga]

I don't think that turning off layers changes the file size, at least not significantly. I tried it on a TIFF and a PSD, and both are the same size with layers visible and with the layers made invisible. The difference is a few bytes. Maybe it's more with adjustment layers and masks, I quickly tried with an image where I simply copied the background layer a few times. Deleting layers will obviously reduce the file size, but that is not what you want to do.

[Guy Burns · Accepted solution]

I have worked out how to reduce the file size in a layered tiff. Assuming you have a Background image layer and several adjustment layers on top – the file size doubles when you do that (to store the extra adjusted image), even though there is no extra image data really required.

The trick is to add an extra image layer, with actual image data, to reduce the file size. What? How can that be?

Well, the extra layer on top of the background, is a posterized layer. I have written a simple Action that adds the layer, asks for the number of levels (typically I choose 16-24), labels the layer in red so that I know to turn it off when exporting to other formats, and the file size of the archived tiff reduces by about half.

I've been more than 10 years searching on and off for a solution. Now I've got it!

[PECourtejoie]

Hello, kudos for sharing the solution for others, I hope they won't be searching 10 years 😉
Please stick around, your thinking outside the box might help others!