How can I disable the image preview on PSDs?

[johnivanwhite]

Hi Folks,

I'm trying to disable the image preview on PSDs, but it doesn't work.

More and more these days I reduce PSD file sizes with a white layer at the top when I save. That shaves huge amounts off the file size. Lie 115MB down to 75MB!

I tried disabling image preview in settings but it has no effect at all.

Hoping someone can help

John

[D Fosse]

OK, here goes:

4300 x 2900 pixels, one extra pixel layer and three adjustment layers. All layers are masked. A fairly standard mid-size PSD.

I then turned compression on, relaunched Photoshop and saved out. Then I added a white layer on top and saved out another copy.

They weigh in at 201.7 MB and 201.9 MB respectively. So correct, the extra white layer doesn't add much, but it doesn't make it smaller either.

Then I turned compression off again, and repeated. This time they came in at 326.2 MB, and 419.3. Much bigger difference.

---

As for using compression at all, my thinking is that if you worry about file sizes you simply can't get any work done.That can't be a consideration. You get new drives as you need them, end of story. To me it's infinitely more important that the compression is incredibly time-consuming. A really large file can take minutes to save and open with compression - but two seconds uncompressed. The priority isn't even up for discussion here.

[johnivanwhite]

Hi D,

Then this is strange because I re-installed Photoshop—having also deleted Preferences files—and Compression is on by default (see attached)—explains the 15-30 second long save and open times; and despite that I get the size-savings with a white layer.

An undeniable categorical fact. I should know, I've done it often enough. I'm curious now to see if don't use compression how huge my billion layer illustration files will be.

The interface is weird, in effect: Click the checkbox to disable compression (which must be on by default), but I understand it. It's not like some I.T. nonsense speak like 'Deselect to un-disenable non-compression.'

[D Fosse]

I'm curious: do you get the same size readings from Bridge?

'Deselect to un-disenable non-compression.'

I like that. Can I borrow it? 

[johnivanwhite]

Borrow away D. One of your developers will love it.

I never use Bridge, No idea what it's for. Photography? Probably not relevant to my work.

[D Fosse]

Maximize compatibility does something very specific: It adds a composite flattened layer to the stack, and other applications use that because they can't read Photoshop layers. That's it, an extra layer. InDesign, Lightroom and, incidentally, the DAM software I use at work, all need this. If you use anything other than Photoshop to handle these files, you need to have maximize compatibility on at all times.

Again, I don't get any saving with max comp on and compression on. It doesn't get much bigger with a white layer added, but it doesn't get smaller either. And neither did Dave up in post #20, with any of the files he tried.

I find it so generally unlikely, in fact, that I'm wondering if it might be a MacOS/Preview glitch. That's why I asked about Bridge, or any other independent confirmation of these numbers.

[johnivanwhite]

It may as you say be a Mac glitch—or it may be a Windows inefficiency. The latter would not surprise me!

[JJMack]

Why would a file formats be different on a Mac or Windows OS. The file is created and Processed by Adobe Software on either platform there is not a Mac version and a Windows version there is a single file that cans be processed on a Mac or PC.  I do not believe that Mac Finder would modify files on access even if it generates Previews it would not  modify users files on its own the previews would not be written into user Image File. Software on either platform can have bugs  in this case if the only the file size is different depending on which platform the file is created on. Is it a real issue when disk are as affordable as they are these days.

[Lumigraphics]

Bridge can read PSD files without Maximize Compatibility.

And if you save a TIFF, you get asked about byte order (which is no longer an issue.) It used to be that Mac and PC processors used different byte order (big-endian vs little-endian.)

[JJMack]

So if you do save PSD with Maximize Compatibility  some Bridge version may find compatibility issues the file will not be useable until one installs the latest version of Adobe software.

[johnivanwhite]

OK, I think I see it now.

'Maximise Compatibility' is the thing that puts up the file size hugely—and (on a mac at any rate) creates the preview image. If it's switched off, you get a blank white preview. Fair enough, you don't get increased versatility for no cost.

To get a smaller file with 'Maximise Compatibility' still on, use a white layer. It works.

But, if 'Maximise Compatibility' means it'll display in an InDesign layout when imported, or some other application, it'll be for nothing if there's a white layer on top. I don't know what else 'Maximise Compatibility' is useful for. Maybe Lightroom or something... I never use that.

So if there's any point in ever having a PSD with 'Maximise Compatibility' enabled, even though there;s a white layer on top, then go ahead and do it, to save space.

Also, with these 70—130MB files of mine, whether compression is on or not makes sod all difference to load times. I haven't tested how quickly they 'save' but they load in between 2 and 3 seconds regardless of compression being on or not.

[bobbybowden]

I hate when people give half information.... where is "preferences"??

[D Fosse]

Have you looked in the menu? Edit > Preferences.

[creativeadvantech]

When I go to image size and try to resample down the image from 3.5GB to 60MB, the "preparing to build preview" and color spinning wheel appears.  How do I turn off the preview in "Image>Image Size" so maybe spinning wheels won't appear?

[KillerRabbit]

Yep dealing with that right now. Never been an issue before.