I’m going to assume that a) you have a fairly good working understanding of Photoshop already, b) you understand that there are exactly one billion ways of doing the same thing in Photoshop, and that if it works and it is comfortable, then it is the right way and c) if you do it differently you know that I’m not trying to tell you you are doing it wrong.
I’m using Photoshop CC2014, but this should be good for CS6 and perhaps CS5 too. For the record, my favourite all time version of Photoshop was CS3.
I’m doing my artwork to look like this, using a green wash. It could be any colour really, I just had some green ink to hand;
I’m going to choose just one of these foxes, cut it out with the polygonal lasso tool and copy & paste it into a new CMYK document;
What I want to be able to do next is to isolate this fox against a transparent background. I want to use the Quick Select tool for that. I know other people prefer the magic wand tool, but I much prefer the quick select tool. It beats the heck out of the magnetic lasso tool every day of the week, but it isn’t a smart tool. From playing with it, it works best and quickest when it is selecting areas of high contrast. To get that I’m going to duplicate the artwork layer to make a dummy layer that we can adjust and then trash afterwards and then open up the levels. (cmd-L)
What Levels does is allow you to reset where ‘perfect’ black, white & grey are. That graph shows you what shade of grey your pixels are. It corresponds to the gradient from black to white below. We’ve got a big lump of white pixels on the right, and in the middle we’ve got a lump of grey pixels which are the ‘black’ lines from my drawing. The smushed up lump between those two lumps we can fairly assume to be the green wash. By adjusting the sliders, I can reset where ‘perfect’ black and white are to get that good contrast the quick select tool works best with.
Now I’ll use the quick select tool to select all the white around the fox. I could select the fox itself, but it is way easier to select the boring ol white and invert that selection. The quick select tool is a lot like an eager puppy. You click and start dragging over the area you want to select, and it bounds off like you threw a stick for it. That can be good sometimes, but not always. It isn’t a ‘smart’ tool.
As you can see down the bottom of the picture, the eager puppy that is the quick select tool just went ahead and selected some of my lines. Use alt-click-drag to remove those lines from the selection.
Next, invert the selection by going to select - inverse (or cmd-i if you are a shortcut wizard) so that instead of the white background being selected, you have the artwork selected. Now go to the original artwork layer and hide the dummy trash layer. We’ll delete that in a moment.
You may at this point be tempted to copy-paste those pixels into a new layer, but first let me show you the Refine Edge tool. This is an option in the top bar when you have a select tool activated.
You know how you sometimes get those annoying white pixels around your beautiful black lines? The refine edge tool allows you to change your view mode to see it against white, black on transparent pixels etc, as well as allowing you to shift your selection in or out, and to feather it slightly to get rid of those annoying pixels. You can output it right into a selection, new layer, layer mask, new document and it’ll even remember your settings which is very useful. The values below seem to work for me;
The artwork should now be on a transparent background all by itself. Go ahead and delete that trash dummy layer. The thing I want to do next is to isolate the black lines from the tones. Let’s isolate the tones first.
Open up levels again and boost the blacks and diminish the whites until you are happy with the tone in the wash. Scanning tends to wash out delicate washes. Here’s the settings I like for this picture;
I want to select all the pixels with their varying transparency. A good way to do this is through the channels, which should be lurking behind your layers palette if your setup is anything like mine. Down the bottom of that palette is a small button with a set of circular dots. If you hover over it, it’ll say ‘load channel as selection’. Click it.
What that does is make a selection of everything that is white. Imagine it ranks pixels while selecting them, so pure white would be 100% selected, while a 50% grey would be 50% selected and so on. That’s handy for us because it will make a selection of our wash quite nicely.
Again, go to select - invert to get a selection of everything that instead of white, is black. and make a new layer. Call this layer ‘tones’ and select it. Go to edit - fill and fill those pixels with a colour of your choosing.
Hide all the other layers to see what you’ve done;
Great. We’ve isolated the tones from the lines. You can argue that no the lines are still there, which I guess they are, but remember they’ll be covered up by the actual lines eventually, so we don’t really need to worry about them at this point.
On that note, let’s isolate those lines from that wash!
Hide the tones layer, duplicate your ‘isolated artwork’ layer and call it ‘mask’. What we are going to do it get rid of the greens on that layer, then do the same channels trick as before, only with just the black lines which we are going to put on a brand new layer by themselves at the top of the stack. The mask layer we will use as a layer mask to make subsequent colouring way quicker. You’ll see. I like to make dummy layers rather than have to go back through the history if I make a mistake.
So, you’ve got a duplicated layer called ‘mask’. Go to image - adjustments - channel mixer.
The channel mixer has some presets. Select ‘Black and White with Green filter’ and see what it does. It should remove (to some extent) all the green colour.
It’s pretty good, but not perfect - there’s some darker pixels that it hasn’t got rid of, so go ahead and adjust the settings to get rid of that shadowing on the fox’s face.
Cool. Now let’s do the same channels trick we did to the tones. Channels - load channel as selection, invert the selection, new layer (called ‘lines’) fill with black, deselect.
OK, that worked, but the lines aren’t perfectly black - they’re something like 60% black, so they were 60% selected, and therefore 60% filled. If you want a nice firm line, duplicate the layer once or twice until you are happy with it’s solidity. Merge those layers if you are sure that is what you want.
Now show the lines and tones layers and have a look. Pretty good.
Next I want to be able to change the colour of the wash and to be able to paint underneath both the wash and the lines too. My first step is to lock the transparent pixels. Select the tone layer and at the top of the layers palette are the lock options - on the left hand side is the ‘lock transparent pixels’ button. This means that when activated, I can’t paint on any pixels that aren’t already filled. I just can’t paint on anything that isn’t there. With this activated, I can use a brush to colour my washes.
And then I just go ahead and paint normally over the bits I want to colour;
Pretty neat eh?
The next step was to set up an underpainting layer with a clipping mask so we don’t have to worry about going over the lines. Make a new layer called ‘underpainting’ between the tones and mask layers. In case you don’t know how this works, let’s try and colour in his shirt first.
Oof. That’s no good. Years ago, I’d have zoomed all the way in and gone over that painstakingly with an eraser. It would have taken FOREVER. There’s a better way, this way.
On your underpainting layer, right-click and select ‘Create Clipping Mask’.
What this does is it won’t show any pixels on the underpainting layer that aren’t there on the mask layer. Because we set the mask layer on a transparent background, I can colour in over the lines to my heart’s content, and the pixels are still there, I just can’t see them if there aren’t any pixels on the mask layer to let me see them.
Look at that! Much better! You could arguably lock the transparent pixels on the mask layer and paint onto that, but I like having options.
The wash layer is a bit washed out and indistinct now, so I’ll duplicate it to bolster it up a bit.
I’ve then gone and cleaned it up a little - this means painting the tone layer white where it got a little messy because I rushed it a bit. Here’s what it ends up looking like;
I know it isn’t everyone’s thing, but I hope there’s something you can find useful here.