Bair Art Edition's Tutorial on:
Adjusting Color & Exposure
In Adobe Photoshop
How to Use Layers: Copying & Saving
Layers make copying and saving a bit more difficult, as well as consuming more file space.
Duplicating a Layer
This even works with the background. It is done by either selecting Layer/ Duplicate Layer... , or by dragging and droping the layer into the new layer icon of the layer palette. That icon is located in the bottom of the layer palette (second from the right).
Quick Tip: After you have made a selection, command - J (Ctrl - J for PC's) makes a new layer above the current one, consisting of whatever is selected.
The method above duplicates the layer and makes a new layer in that document. To copy the information of the layer (say for another document) select all (command - A for Mac's, Ctrl - A for PC's), and copy. Then paste where desired.
Copying a layer is only accomplished after making a selection. In theory, whatever is selected will be copied. However, this is not always the case!
For example, if you copy layers with lowered opacity (say 50 percent), when it is pasted to another document it is 100 percent again. Also, vector-based items and styles won't copy unless they are merged. See Merging Layers for more info.
For copying all of the layers in a document at once without having to flatten the image see Merge Visible - Advanced.
Layers will increase the file size, period. This is an unfortunate circumstance, but I don't know of a better alternative. Still, there are file formats that deal better than others.
Photoshop Document (.PSD) is the only format you should ever save layers in. This is especially true when dealing with Adjustment Layers. Photoshop is able to save Adjustment Layers as simple settings, without needing to make them entire layers the size of the image.
TIFF is capable of saving layers, but it results in a much larger file. The reason is that it must save Adjustment Layers as a complete layer, the size of the image.
JPEG is never advised! If you are publishing to the web, or never plan on adjusting the image again, you can save it as a .jpg, but otherwise stay away from this! JPEG needs layers to be flattened, and the file information is compressed to one degree or another.
No Need to Make a New File
Do your folders look like mine: Emily.jpg, Emily.psd, Emily2.psd, Emily_enlarged.psd . . .? Do you really need to make so many files? Not really.
As long as you preserve the original information on at least one layer (often the background), then you only need to keep one file. The layers themselves can serve as the old files to fall back on. If you have old layers that you want to not clutter your palette, just put them into a set and hide them.
Create a new set by clicking on the icon which looks like a folder at the bottom of the layers palette. Then drag the old layers in to the set (folder).
These are the other sections of this module: