Export tiff with no layer and save as a copy – different file size, why?

[Organic Dave]

Hi!

I'm looking for an answer why same file has different file size.

I have an image with only one layer "layer 0". If I save it as a tiff I get around 3 times bigger file size then if I save the exact same file with the option "save as a copy" with "no layers" box checked. Why?

I would, of course understand if I had several layers thrown away by saving with "no layers". But I have "merge visible" before saving so the file just have "layer 0" left. No extra chanels or path does not exist either.

[PECourtejoie]

Hello, you should do a flatten image, otherwise, an extra preview image (composite) of the result of the merging of all the layers is included, even if there is only one layer, as it might have transparency, for instance.

[Jumpenjax]

I agree with PECourtejoie, but one more thought save your file as a .psd file first before you flatten. Then you have a backup for any changes you may need in future.

[Alexandre Becquet]

Hello, like @PECourtejoie and i would like to ask why Tiff because it's a very old format and not really good for actual work. You should try PSD or PSB, depend on the size.

If i not wrong Tiff is on the version 6.0 since 1992, no update since this year.

[TheDigitalDog]

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@Alexandre Becquet wrote:

Hello, like @PECourtejoie and i would like to ask why Tiff because it's a very old format and not really good for actual work.

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Actually, unless you do a lot of work in InDesign, the ideal file format is TIFF! TIFF supports everything you need that a PSD can and is more future proof, openly documented, supported in more products etc.

http://digitaldog.net/files/TIFFvsPSD.pdf

From Jeff Schewe:

Wrong...PSD is now a bastardized file format that is NOT a good idea to use. Even the Photoshop engineers will tell you that PSD is no longer the Photoshop "native" file format. It has no advantages and many disadvantages over TIFF.

TIFF is publicly documented, PSD is not. That makes TIFF a preferred file format for the long term conservation of digital files.

TIFF uses ZIP compression for max compression, PSD uses RLE which if you save without the Max compatibility will be a bit smaller, but at the risk of not being able to be used by apps, like Lightroom.

TIFF can save EVERYTHING a PSD can save including layers, paths, channels, transparency, annotations and can go up to 4 GIGS in file size. TIFF can save all the color spaces PSD can. The ONLY thing I can think of that PSD can save that currently TIFF can't save is if you Save out of Camera Raw a cropped PSD, you can uncrop the PSD in Photoshop CS, CS2 or 3. That's one tiny obscure thing that PSD can do that TIFF currently doesn't. How many people even knew that let alone use it?

PSD used to be the preferred file format back before Adobe bastardized it for the Creative Suite. The moment that happened, PSD ceased to be a Photoshop "native" file format. PSB is the new Photoshop "native" file format for images beyond 30,000 pixels. And , at the moment, only Photoshop can open a PSB.

Getting back to the fist point, Adobe can do anything including stopping support for PSD because it's a proprietary  file format. TIFF is public, even if it's owned by Adobe (by virtue of the Aldus purchase). Even if Adobe went belly up tomorrow, TIFF would continue.

And, let me be blunt, anybody who thinks PSD is "better" than TIFF is ignorant of the facts. If Adobe would let them, the Photoshop engineers would tell you to quit using PSD. Lightroom for the first beta did NOT support PSD and Hamburg fought tooth and nail to prevent having to accept PSD. He blinked, but you still can't import a PSD without Max compat enabled-which basically makes it a TIFF with a PSD extension.
Look, I'll make it REAL simple...
TIFF = Good
PSD = Bad

Ok?

[Park Street Printers]

I always save all full-resolution files as a tif for these reasons. I am so grateful that someone else champions this!

[D Fosse · Accepted solution]

Flattening a file discards a great deal of information. A flat file is nowhere near the same as one with a floating layer, even if it's just one layer.

For instance, you may have "hidden" data outside the canvas boundary. Flattening the file throws that out.

[Organic Dave]

Just to be clear - when working with the image I use PSD. When I export the image to the designers I export as a Tiff. But that was not my question. I'm asking if someone knows why an exported Tiff file size is bigger if I export it with "layers" box checked when saving compered with "save as a copy" that discard the layers, when the original file do not have any layers? I would of course understand why, if I saved with layers and I had layers but the original file do not have layers, path or extra chanels. What is the extra info saved by "saving with layers" compered with "save as a copy" (from a file without layers)?

[D Fosse]

And I answered that question. A flat file is not the same as a single floating layer.

A floating layer has the whole structure of anything that is supported in Photoshop.

A flat file is an array of pixels and nothing more.

[Organic Dave]

What is the difference? I have posted two files for a test. I cannot see any difference except the file size.

By using "Flatten image" and "save as a copy" do not make the same effect. Flatten image make the layer to a background and deleting the transparency, save as a copy do not delete the transparency or make the layer to a background.

[D Fosse]

"Seeing a difference" is not the point here. The underlying file structure is.

Have you checked whether you have hidden data outside the canvas boundary?

[Organic Dave]

There is no data outside the canvas boundary. For me this is a huge thing – I work with beetween 50 to a 100 images every month. For an example, my .PSD working file is in this example 304 mb. When exporting the file to the designers, "save as a copy" makes the size of the file 8,9 mb. Saving with layers make the file size 18,8 mb. Before doing this I "merge all visible" and deletes all extra chanels and paths. There is no data outside the canvas, the file do not have any hidden layers or extra information. The why is there such a huge dirrence in the file size? What is the extra info the file with layers is carrying?

[PECourtejoie]

Hi, I thought we clearly explained it...

If there is anything other than just background layer in the layer stack, a full preview is added in the file, similar to when you have "maximize compatibility" on on a PSD. It might also need a full "alpha" channel, as each pixel can have various amounts of transparency.

[Organic Dave]

OK. Have you seen or noticed anything negative in "save as a copy"? I have run different tests and can not see any difference, all the image bank programs is reading my file that is "saved as a copy" the same a exactly the same file but "saved with layers". The transparency looks the same, the information in the preview looks the same etc.

[D Fosse]

You seem stuck on "save" versus "save a copy". That's irrelevant, they are both the same - as long as you save to a format that supports all the properties of the file. TIFF supports everything, so there is no difference.

You can "save" with or without layers, and you can "save a copy" with or without layers. Your choice.

The main purpose of "save a copy" is to save out to a format that does not support all current file properties, like jpeg or png if you have layers. Then you need to save out a flattened copy.

[PECourtejoie]

There is nothing negative, the only thing "Save a copy" does when your file has a layer is to flatten it, IE, discard the big data (anything that might be stored around your image), remove the need for a composite preview, and the need to store the alpha for each and every pixel in the image, all things that are as costly in file size as another pixel, if uncompressed...

Maybe you have removed it, but the first time you save a tiff with a layer 1 instead of going to Layer>Flatten Image first, you will see a pop up window telling you that saving with a layer will increase the file size.

Maybe did you click on the do not show again long time ago, but you've been warned, it is expected...

[D Fosse]

A floating layer is more complex, with a lot of supporting overhead. That's just the way it is.

If you think the overhead is excessive, then that's a technical discussion you need to take with the Photoshop engineers. Only they can answer that.

[kenGo]

Not a solution, but a work around for this is to add a layer of solid white as your top layer in the photoshop file. This will make the layered PSD/PSB file smaller in size. We use Tiff a lot in our proprietry applications and we work with images of up to 100,000 pixels square and that white layer saves a few GB of disc space