this is going to be the worst tutorial ever and i have no regrets or shame
NOTE: mileage may vary since i'm using photoshop 7, but i don't think it's all that different in newer versions.
so, layers. they're pretty awesome. you make an edit you want to be able to delete in an instant? new layer. you don't want to mess with anything on the base image? new layer. you want some neat shadow effects? new layer. layers are the digital artists and graphic designers' way of preventing fuck-ups.
SO ARE YOU READY TO START USING SOME FUCKING LAYERS??? LET'S DO THIS SHIT
STEP 1 - create an image
i copied an image directly, and when i created a new image it automatically created an editing window with the same dimensions.
here's my layers screen:
i'm on the background layer, which in the editing window is just a lot of white. i actually took this cap after i did another step, so... hence the second layer already. but the gist is, this is the background layer, which is the foundation. every layer you make will pile on top of this layer. a lot of the time, if you're drawing something, this is the layer you draw on. (for the record: don't draw directly on the background layer.)
STEP 2 - add content (to the second layer)
since i pasted the image directly, it appeared as a new layer automatically on top of the background layer. i'm now on this new layer.
you can tell what layer you're on by whether or not it's highlighted:
and here's my editing window so far:
if you're doing some art, i suggest copy/pasting line/baseart you were working on to this layer.
STEP 3 - add content again to a new layer
create a new layer, via the button i have highlighted:
again i got ahead of myself, so... lots of layers you wouldn't have at this point. :x
so, this new layer? try drawing on it. draw anything. even, say, a dick.
did you think i was kidding?
now, perhaps this dick won't turn out exactly how you want it. but that's okay! you can erase any part of it, and keep on redrawing as much as you want, without fear of messing up your base image. keep on going at it until you have the best dick you can produce. (mine's not very good, but give me a break, i color with a mouse and it's not like i practice drawing dicks or anything.)
...okay yeah i do but that's beside the point MOVING ON
STEP 4 - add yet another new layer (sense a pattern?)
this dick could really do with some detail. let's use this layer to make it more realistic!
here, let me explain a nifty property layers have. above the layers box, there's a drop down list, automatically listed as "normal." a normal layer is just that: everything you do will be literally that. if you draw on a normal layer with the same dick-color you've been using, it will come out in that dick-color. however! if you select "multiply" from the drop down list, and draw over the already-existing dick, you get a darker shade! multiply makes colors a bit darker. (it also makes white transparent, in case you have something white on this layer.) on the flipside, screen makes everything lighter, and black transparent. you might want to take a few minutes to play around with these settings to see what all they do and how you'd best use them. the ones i just explained are the only two i personally find myself using, though.
so, now that you've fooled around, erase everything on the layer, or even delete the layer itself (right click > delete) and recreate it, and draw some details on that dick! multiply for veins optional.
i decided to take it a step further, and even drew some jizz. but what's this? gahhh. thanks to multiply, the jizz is see-through! D:
LOOKS LIKE IT'S NEW LAYER TIME YET AGAIN
STEP 5 - you know what's coming
make another new layer! now, this layer is immediately on top of the dick-detail layer. if i draw the jizz white, that will cover up the actual jizz lineart, and that's not good. so what i'll do is drag this layer to be underneath the previous, like so:
so here'd my finished product after my jizz-coloring with white is done:
TADA~
and that's really all there is to layers! just keep making them so every step is separate, and it makes editing anything a lot easier, since you can just delete or erase if something comes out wrong!
i'll mention i was really lazy with this, since this is a quick'n'dirty guide and i wasn't intending to use too many layers. to keep track of things on more detailed work, you can right click > layer properties on any layer to rename it to something descriptive. very handy!