Adjustment layers calculate or show you only preview how image will look if you decide to export it with applied adjustment. When using Adjustment layers you are not working with pixels and everything can be changed at any time till image is in PSD format (or layered TIFF). You can change Adjustment later or even delete it without affecting pixels in image in other words same as nothing was happen.
Adjusment layers are effect layers that affect all layers below them. Artists like using them because they can easily be toggled On or Off, unlike regular filters/adjustments (with the exception ones applied to smart objects) that permanently change the image. However, they are not always a good substitute for filters because they affect all layers below, making them undesirable if you only wish to affect a single element.
These are layers that adjust the presentation of those lsyers below i.e blurring
until you merge layers or save in picture as .jpg
There are many resources and websites that offer information about Photoshop layers. Some of these websites that offer information are Adobe, Photoshop Essentials and Photoshop Cafe.
Curves is adjustment in Photoshop where you can adjust colors and tones in an image.
You don't need to use an adjustment layer, an adjustment layer will effect any layers that are under that layer, and you may not want to affect all layers, just one. An adjustment layer is good for non-destructive editing, because it can be easily turned on or off, or deleted without making any permanent changes to the pixels of the lower layers. You can also mask out certain parts of the adjustment layer by adding a layer mask so that it will only affect a selected area, but remember, it will still affect all layers under the first one, which may not be preferable if the layers have any transparency.
color layers is simply color layers
Open the Layers window.
Yes, .psd files maintain the layers you create in Photoshop so that the next time you open your .psd file in Photoshop you can continue to work directly onto the layers.
One layer.
To store image parts.
Vibrance adjustment starts with cs4
To select all layers in photoshop for a PC open up your layers window (It is under window - layers), hold down the shift key and click on each layer that you want to group together or edit.
One way is to create clipping mask. First create layer with adjustment you want to apply to several layers on top of last layer of group you want to change, then select all layers you want to apply that adjustment by holding Ctrl while clicking layer one by one, then navigate kursor at line when adjustment layer touch layer below (last layer of group you want to change), hold down Alt key and cursor will change to little triangle with two squares behind, then click left mouse button and you will create clipping mask, adjustment layer will affect only previously selected layers.