WHY LAYERS?
If you are new to Photoshop, and photo editing software you may never have seen a layers panel, or might not even know what a layer is. Many beginners just want to edit their photos, and are overwhelmed by the array of tools presented to them, so they dive right in making all the edits on their background layer. Sometimes they get lucky and everything works and their image looks great, but more frequently edits need to be adjusted or changed. If you work ORIGINAL IMAGE on your background layer with out
making a copy or using non-destructive adjustment layers you have to back up to where you made the edit you want change. This would be okay if you only have to go back a step or two, but a disaster if you have saved your work, since your original photograph is now gone and in its place the edit you did not want.
Curves Adjustment
So the first thing many newbie’s do is make a copy of the image, and then make an adjustment to the layer (I did this too when I first started, layers baffled me.), Bravo! This is a non-destructive edit, your original photo is still in tact, if you need to go back to the beginning you still have your image, you just turn off or throw away the new layer. Let us follow this a few steps and you will see how cumbersome this process becomes. Beginning with the original image, make a copy, and go to Image > Adjustments and make a curves adjustment. By grabbing the curve and moving it to where it works for you. All seems good, and it is so far.
Hue/Saturation Adjustment
Filter Layer
ORIGINAL IMAGE
To apply another adjustment without destroying the last adjustment layer, you would copy the layer with the curves adjustment by either dragging the layer to the icon next to the trash can at the bottom right of the screen or select Layer>Layer via copy or use the shortcut command/control J. Now apply a hue/saturation adjustment, again this works easily. All done with adjustments, I final step we want this to look a little like a drawing so we make a copy of the original layer, dragged it to the top in the layers palette and apply a filter. In this case, I used an artistic filter, turned the layer from Normal to Overlay, and adjusted the opacity so the original image could show through.
Select Adjustment Layer
Curves Adjustment Layer
If you do not like something, you just turn off the layers or discard them in the trashcan. So now, you are wondering what is all the discussion for, this all works. Yes it works, but does it work as well as it could. The answer to that question is no. Why is that, you
Hue Saturation Adjustment Layer
ask, more importantly, why do you care? First you are always making a copy of the last layer you worked on, in order to keep your adjustments separate, but more importantly you are missing one of the best tools in Photoshop, and they are called layer masks. When instead of just using a Layer>Adjustment you select Layer>New Adjustment Layer and pick the adjustment you want to make you get this added bonus of a empty box that is called a layer mask. Hmmm, you say.
What does that do, you ask. Well, it gives you the option of adjusting all or just some of your image. Say you do not want curves or all the hue/saturation in an image, by selecting the layer mask box and black paintbrush paint on the image where you DO NOT want to make any changes. One can even change the opacity of the brush so that it makes some level of change. If you make a mistake, all you need to do is change the brush to white and paint back what you want included in the adjustment. This allows you to make countless edits and adjustments without destroying you original image and you can fine-tune your image nearly down to the pixel level. This is only the beginning of what layers and layer masks can do for your image editing. Questions?