Photoshop Reducing File Size by Hiding Layers


I've recently learned that hiding Photoshop layers will reduce the file size.

After searching around the Adobe forums I can't find anything stating this. There are only about half a dozen sites on Google that I found mentioning this trick as well.

I have a 300mb file with roughly 6 layers. When the layers are hidden it trims about 100mb off of the total file size.

I'm wondering what information is either compressed or lost by hiding layers? Will the file still be safe for print? Will the file still maintain it's compatibility options for other programs like Lightroom?

All of the articles I found talking about this trick don't explain exactly what's going on with this, and what information is being left out or compressed. Any ideas would be appreciated. Thanks!

4/6/2013 5:30:00 PM

I just did the test and in fact in my test with all layers hidden got a file about 1 MB smaller.

I proceeded to save it with all layers visibility on but this time disabling the "maximize compatibility" option - the result was the same.

So the thing is, Photoshop saves some kind of high res preview of the file when "maximize compatibility" option is turned on. This info is then used in programs like irfanView, google viewer and even adobe bridge for previewing purposes. With all layers visibility hidden this preview will be essentially empty thus the file size decrease.

You can turn off maximize compatibility in preferences > file handling

4/6/2013 5:49:00 PM