This tutorial shows an example of how masks can be useful when creating original illustrations in Photoshop.I've gone a bit into explaining masks in general, but not the absolute basics, so it helps if you atleast know where all the buttons and commands are in PS.I'll also explain what I think is a good allround way of sketching from the ground up. A fairly detailed sketch is required for this method of masking to work out right.As the example in this tutorial I've used my illustration:I chose it because it's a picture where masks really worked out great. With a little brainwork of your own I'm sure you can gel this information with your own methods.Here we go....
Sketching in Photoshop has many advantages over natural media. For one thing, you can easily erase or adjust while sketching, and you end up with a composition that is, if not done, then almost.I sketch with a fairly big semi-soft brush (penpressure controlled size and opacity), and a big, rigid eraser (pen contr. size only). Brush foreground color is set to a warm mid-level brown, brush background color is set to the paper color (in this case white).If the sketch has several complex items, I usually work on them in separate layers, so I can easily erase overlapping objects. This image is fairly simple so it's all done on one layer. After sketching is done I resize, rotate and move some bits and pieces slightly with the Liquify tool.If I'm unsure of any proportions I might flip the image horizontally to check if anything looks odd, edit the odd part, and flip it back.After all this I flatten the image, and the "pencil-sketch" is done.
Sketch coloring is good, because it gives me a better view of what the finished image will look like.On a new layer set to multiply (or gel in Painter), I paint the various colors I want, not worrying about edges that much for now. On another layer on top of this one (set to normal) I paint with a 50% opacity brush in black and white, highlighting and shading based on the direction of my light source (in this case the sun, "off camera").I colored this sketch both in Painter and PS, can't really recall the exact brushes used because I was just experimenting.
This is the part where I tried a new (to me) approach to layer masks. Earlier I've either painted a completely new image in layers on top of the sketch, or created a mess of layers merging with the sketch to make the final pic.This time I copied the flattened sketch to several (4) new layers, and made layer masks for each copy. If you're fairly new to masks, in this case they mimic the matte painting technique used in movies and animation. It's a great way to separate objects in the foreground from the background.To help me see what I'm masking out, I use a 50% opaque layer with a bright blue fill between the layer I'm masking and the background.I mask all the layers from foreground to background. These layers will now act as a base clipping-layer (new PS CS term) or group (older term). In essence, anything painted on a layer which is on top of the masked layer, and grouped with it (Ctrl+G) will only show what is within the base masks borders.Masking can be done with either lasso or a hard brush. Using a soft brush is usually not a very good idea, if your mask has a very complex outer edge (for example the grass in this image), it's probably better to make a rough mask as a base, and add grass to an ungrouped layer on top. Alt-clicking the layer mask in the layer palette helps you see if you've missed any spots.Some of the internal details get their own masks to make sharper outlines.
This is where everything becomes one big blur :)Basically, add as much details and polish as you like. I usually "sweep" the image several times, each time going into smaller details. It's a good idea to take a break from the image once in a while, doing it all in one sitting can make you miss something. Another tip is to print out your work in progress, and circle parts you'll need to work on with a pen.
When I'm staisfied I can't possibly cram any more details into the image and still like myself, I make a merged copy of the whole image to a new layer (Shift+Ctrl+C, Ctrl+V). On this merged copy I try out some level adjustments to give it more oomph. In some cases some color adjustment (with for example selective color) on the merged copy might help the pic as well.Before:After:And that's it.