TIFF - save as vs save a copy

[fafor]

Hello.

I want to save an image as TIFF 16 bit ProPhoto RGB. All the layers have been merged down just to one. There is no transparency or anything outside of the canvas. When I save as I get 500 mb TIFF and it always says that including layers will increase the size. I discovered that when I save as copy without layers the files are 50% lighter.

With what I described above do I lose any necessary data when SAVING AS COPY?

[didiermazier]

Hi,

With a heavy file problem, the first thing to do is to check the size of the pic. Command(or CTRL on PC)+ Alt +I

You can the see if it is possible to downsize the image.

How many pixels (or size/res)?

[fafor]

7680x5760

[didiermazier]

If the purpose is to print for a 260 px/inch the size would be 29 inches/22 inches. This seems to be a poster…

If you just need lets say a magazin cover you would only need around 2500 pixels… so you can keep the original and downsample a copy for export. It should not be so heavy…

And by the way you can use LZW compression with Tiff pics, which is not destructive.

[TheDigitalDog]

Save, Save a Copy, doesn't matter in terms of what the size will be with layers; the layers and the degree of data on them play a role. IOW, if you had a layer filled with pixel data, it would take up more space than a layer with a lot of transparency and few pixels. YMMV. 

If you Save a Copy and flatten it, you still have the original with the layers so you don't lose that of course. You lose a lot in the flattened version if you didn't have the original and wanted those layers to re-edit. So yes, not saving the layers (Flatten then just Save) makes the document take up less space on the drive. At a possible price. 

[D Fosse]

A single floating layer (Layer 0 in the layers panel) is not the same as a flat background layer (Background, in italics, in the panel).

A floating layer can potentially support a large number of file properties, and the file structure is much more complicated even if the "shelves are empty", so to speak. Flattening to Background simplifies the file structure considerably and the file size goes down.

One particular thing to be aware of is that a floating Layer 0 can contain data outside the image boundary. This can happen if you crop with "delete cropped pixels" unchecked. Flattening will discard those outside pixels.

[fafor]

Thanks all 🙂