Merging vs. flattening

Izzy Garavito

what's the difference between going to layers->merge or layers->flatten? I get the same effect using either.

Also, is there any way to sharpen in LAB mode without having to lose all your layers (IE having to flatten or merge them into one)?

Thanks a ton,

Izzy

pyrtek

Flatten merges all the layers in the pallette, while merge merges layers
based on which merge method you choose. For example, merge visible merges
all the layers which are visible (have the eyeball on). Flatten also discards all
the layers leaving only the flattened one as the new Background layer, while
merge creates a new merged layer on top of all the already present layers[*].


* Or, more accurately, above the currently selected layer.

colourbox

To add to that, with Merge you can merge selected layers, so if you have 13 layers and you select layers 1, 4-7, 10, and 12, you can merge just those and the rest are left alone in their original order.

Merge won't create a Background layer if there isn't one already, even if you Merge Visible or merge all selected. Flatten always results in one Background layer, no matter how many layers were there before or even if there wasn't a Background layer before. You get no choices, Flatten is all or nothing.

Another way to understand the above is, Merge lets you preserve transparency while Flatten always removes all transparency (thus the single Background layer).

Izzy Garavito wrote:

Also, is there any way to sharpen in LAB mode without having to lose all your layers (IE having to flatten or merge them into one)?

The usual advice here is don't go into Lab mode. Instead, apply Sharpen and then fade using Luminosity for an effect that's approximately the same as sharpening in Lab. If you are trying to do it to a bunch of layers together without losing them, turn the layers into a Smart Object and apply sharpening as a Smart Filter (this is in CS3 only) and then set the Smart Filter to Luminosity.

Izzy Garavito

excellent info. thanks a ton. When I use merge I still get only one background layer. So if I have my color correction layer, a general exoposure layer, a subject exposure layer, hue/sat whatever, and I merge, then go into Lab and sharpen the luminosity layer, how can i go back and get all those layers? I still end up with a single background layer

I use CS3

Thanks again for the quick reply

Izzy Garavito

the thing is, I'd like to save my photos with all the layers, ready to go. that includes sharpened. Currently I have to merge them or flatten them all before sharpening, then save the sharpened image without any of the layers

jfriend

Izzy Garavito wrote:

excellent info. thanks a ton. When I use merge I still get only one background layer. So if I have my color correction layer, a general exoposure layer, a subject exposure layer, hue/sat whatever, and I merge, then go into Lab and sharpen the luminosity layer, how can i go back and get all those layers? I still end up with a single background layer

I use CS3

Thanks again for the quick reply

You often can't take layers with any sort of curve or blend mode in them between different image modes (sRGB to LAB, for example). You have to flatten before changing modes or it will flatten for you or it will keep the layers, but their effect will get messed up. This is because not all operations are supported in all image modes and not all operations have the same effect in different image modes.

When I have a heavily layered document that I've invested a lot of time in and then I decide I need to go to LAB, what I do is I make a duplicate of the layered document, flatten that. Take that to LAB, do my LAB operations, flatten, convert back to sRGB, then copy to the clipboard and paste it in as a new layer on top of all my other layers. The other layers will no longer be active because they've been superceded by this new layer that came from LAB, but they are still there if you have to go back and make changes, you can just redo the LAB adjustments without having to redo everything else.

Izzy Garavito

Dude, $. why hadn't i thought of that :bash Thanks a ton

SloYerRoll

colourbox wrote:

To add to that, with Merge you can merge selected layers, so if you have 13 layers and you select layers 1, 4-7, 10, and 12, you can merge just those and the rest are left alone in their original order.

Merge won't create a Background layer if there isn't one already, even if you Merge Visible or merge all selected. Flatten always results in one Background layer, no matter how many layers were there before or even if there wasn't a Background layer before. You get no choices, Flatten is all or nothing.

Another way to understand the above is, Merge lets you preserve transparency while Flatten always removes all transparency (thus the single Background layer).



The usual advice here is don't go into Lab mode. Instead, apply Sharpen and then fade using Luminosity for an effect that's approximately the same as sharpening in Lab. If you are trying to do it to a bunch of layers together without losing them, turn the layers into a Smart Object and apply sharpening as a Smart Filter (this is in CS3 only) and then set the Smart Filter to Luminosity.

Great stuff CB. Thanks.

-Jon