photoshop: merge and flatten

[Marquinius]

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Although I've been using PS for a couple of years now, I only recently started going in a little deeper in what is possible with layers, LAB color, etc. And I read some help files, but most of them tell you what to do, but not what's happening and what the real diffences are.

 

So here's a fairly rookie question: I was working on a photo and automatically flattened some layers. At one time I used "merge" and didn't think anything of it. Now I understand that with merging you can point out several layers and merge them, while keeping others as separate layers. So far so good. But does it essentially do the same and give the same end result print wise?

 

Marco

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[Shootist]

To my knowledge PS always uses the top layer down to display a image and from my experience printing a image with layers, not flattened, gives the same result as if you merged all layers or flattened the image.

I haven't done any real scientific tests on this it is just from what I see on screen to what I see in the print. Printing non fattened or merged images looks just like what is displayed on screen just like printing images that have been flattened.

 

I guess if you are working on a very large image with many layers it could take longer to print and or run out of printer/computer memory then a image that was flattened.

[roguewave]

Marco, a great question. I'm sure we will get a more authoritative answer from Rob, Rolo, William or some other PS wizard. Personally, if I have an image that's important to me (for whatever reason) I will keep copies at various stages, without flattening, so I can always go back & change or review how I got there. You can always make a copy, rename & flatten it to print.

 

Recently Rob gave me some instructions regarding toning & cleaning up the mess I leave when a "paint with light" in a more abstract expressionist venue. His techniques are excellent & you don't need to flatten if you can stand the larger file size.

 

The real issue with merging & flattening is that it is destructive. Once done, the pixels are altered, irrevocably.

[haribo]

Although I've been using PS for a couple of years now, I only recently started going in a little deeper in what is possible with layers, LAB color, etc. And I read some help files, but most of them tell you what to do, but not what's happening and what the real diffences are.

 

So here's a fairly rookie question: I was working on a photo and automatically flattened some layers. At one time I used "merge" and didn't think anything of it. Now I understand that with merging you can point out several layers and merge them, while keeping others as separate layers. So far so good. But does it essentially do the same and give the same end result print wise?

 

Marco

 

Merging of layers can be beneficial or necessary during work in order (to be able) to apply certain effects or filters and such.

There is a way to merge and yet keeping the original layers separated.

Activate the layers you'd like to merge, press Option (on Mac) and then merge (if you use Merge visible, don't forget to deactivate all other layers you won't want to merge!).

By pressing Option while merging, a new, combined/merged layer gets created on top of the original ones.

 

Flatten all layers is like a final step. If you have the capacity to store big files I would do the following: Create a psd file with all the layers. And for printing/final sharpening purposes, flatten and then 'Save As' a separate tiff file.

 

Hope this helps.

[johnwolf]

Marco, this is a little off-topic, but you can also merge all layers into a new layer, stack it on top, and keep all the old layers intact. Sometimes you want to apply an effect to all the layers but don't wish to lose them.

 

In Windows, de-select all layers, then click CTRL+Alt+Shift+E.

 

John .

[adan]

One key difference in addition to all those previously mentioned:

 

"Flattening" an image will discard any transparent areas, whereas "merging" layers into a transparent "Layer 0" background will preserve the transparency, so long as you are using a final format that supports transparency, while still reducing the data size to about that of a flattened image. .PNG files support transparency - I don't know which others do.

 

That's probably more important for web and video production than for printed photographs/images, but it is a significant difference.

[Marquinius]

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I never realised my question would offer such a broad scala of advice! Two things are more clear now to me.

 

Flattening is something you only do just before final output (i.e. printing, whatever) and preferably you hold on to a non-flattened file. Disc space is no real issue anymore imho.

 

You can work with all layers BUT can create a separate "combined" layer for further PS purposes on top.

 

Everybody: thanks sofar, it is really helpful and points me in a general direction. Hmmm ... now I'm thinking of the difference between "merge" and "merge all visible". Perhaps I should open my books again and read a little more about this.

 

Marco

[Philinflash]

...

 

Flattening is something you only do just before final output (i.e. printing, whatever) and preferably you hold on to a non-flattened file...

 

Marco

 

Unfortunately, you have to flatten in some situations well before "final output." For instance, if you are cloning, healing, and/or transforming, you cannot do that with multiple layers open.

[Guest WPalank]

Unfortunately, you have to flatten in some situations well before "final output." For instance, if you are cloning, healing, and/or transforming, you cannot do that with multiple layers open.

Absolutely not true.

Command-Option-Shift-E (PC: Ctrl-Alt-Shift-E) will will merge all of the layers into one new layer and insert it at the top of the layers stack leaving all the layers below intact should you want to go back to them.

[Philinflash]

Absolutely not true.

Command-Option-Shift-E (PC: Ctrl-Alt-Shift-E) will will merge all of the layers into one new layer and insert it at the top of the layers stack leaving all the layers below intact should you want to go back to them.

 

I am always pleased to have pointed out when something I write is "absolutely not true" given my love of absolutes and my interest in learning something new. For one thing, I was completely unaware of the keyboard shortcut you describe or the functionality it initiates. I now see that Adobe calls this function (rather opaquely) "stamp all visible layers" in page 293 its help pdf file. Very interesting. Forgive my ignorance of Photoshop arcania. Now that you have pointed this out to us, I am sure I will enjoy some use of it. For instance, this function will be a good step to precede certain modifications as I mentioned in my post above without compromising the underlying layers as would occur with a simple "flatten".

 

Thank you.