The first thing I did when, when I purchased my first 10" android tablet, was to was to scan the play store for apps that would help my in my obsession to create. Not to sound like a commercial here, but one of the best apps I came across, if not the greatest, was Autodesk's Sketchbook Pro. I started off with the free version and often used it to sketch out plans and designs for new projects, or to modify images into stencils (which I'll get into later), but I never really used it to it's full potential. There are some fantastic aspects to Sketchbook and some parts that could use a bit of improvement, but it's definitely something that, I feel the positives outweigh the negatives.
I've done quite a bit of airbrushing and canvas work, but I've never really been into drawing as an art form. I found it interesting that using the tablet was more effective when used employing airbrush/canvas techniques, and that the deficiencies with the over sized stylus could be easily overcome by employing that small shift in style.
This instructable is on a technique I use to create realistic images, tho I can't say I created it because I really don't know. As I said, it's not my standard medium of work so I'm certain there are others, out there, that are more adept at it than I. This technique uses a 'base' image, strictly, as a reference and the drawing is created using layers where finally the original image is deleted. It'll work on any image whether drawn from pop culture, as my demo prints are, or from images that are taken using your own cell phone. It almost seems like cheating, but as the original is only used for the outline, and color reference, you'll realize that the rest; airbrushing, blending and texturing are entirely up to the person behind the stylus.
I've posted a couple of pics so that you can see the difference between the two versions of Sketchbook. The Fight Club and Clockwork orange pics were both done on the free one, while Metropolis, Boondock Saints and V were all done on the Full version.
Step 1: Choosing a Stylus
Having tried a wide variety of stylus types including brushes, DS stylus, homemade headphone wire pen, even a Jot Pro, but I always come back to the rubber nib which has some major advantages for me.
First is pressure. Applying a light pressure on the nib is fantastic for shading light areas of your work, or drawing straight lines, whereas a heavier pressure can cause your lines to be more erratic which would be better if you were, say, applying a texture to an area.
Second, rubber nibs offer some friction with the screen without harming it. That means you have a real physical connection to your work, much like a pencil to paper, where the amount of pressure used can mean a lighter or darker line.
Third, they don't skip as much. It can be frustrating when you're trying to draw straight, and it keeps skipping, leaving dashes instead of a solid line.
Fourth, they're cheap and abundant. I've custom made mine using the finest nib I could locate from a stylus bracelet that was given to me when I bought my cell phone, but I keep 2 or three different kinds, and have no problem switching up as needed.
Step 2: Layers and More Layers
Everything, is done in layers, that way, if a mistake is made that can't be reversed, you only stand to lose one layer instead of having to correct, or even start the image over. More than that, the higher the layer is on the list, the more visible it is over top of the others which is great for shading over solid colors.
For this technique, we use a photograph as our base image. Tap the layer and it'll bring up a menu. Tap your import photo button to call up the image you're planning to use. As mentioned before, it's only function is to serve as a 'template' for the picture we're going to create. Make sure your image is edge to edge or you will end up with a white border.
Next, you'll click the plus sign and create a new blank layer above it. This is the layer you're going to draw your outlines. It's difficult to tell you how you should trace it, however what you're looking for is a well defined line art image of the original. On the free version, I recommend using the pencil tool with a radius of 1.5 and an opacity of .86, however, if you purchased the full version, you can use the HB or F drawing pencil tool. Once you've finished outlining the original image, you're pretty much done with it, other than using it for color and texture reference. If you click on the eye icon in the upper left corner of the layer, it will hide it without deleting.
Now, you're ready to start the airbrushing and shading. Hit the plus again, and create another layer. This one should be below the line layer, but above the original image. It's in this layer we're going to work from now on. As you're working on airbrushing different areas of your sketch, I highly recommend creating new layers, then merging them, down, to a 'main' color layer as you're satisfied with them. Don't merge anything into the 'base' image. We'll be deleting it at the end.
Adjusting your Image;
If your image is skewed, doesn't fit the page, or has parts that you don't want, you can click the 3 dot icon on the top bar, then choose transform to adjust it. Remember, Sketchbook has a defined drawing area so anything beyond that will be cropped. Each individual layer can be manipulated this way just by making sure it's box is highlighted.
If you are working on a lower layer, and can't see clearly through the one above it, you can temporarily adjust it's opacity simply by selecting the layer, then sliding the bar to the desired level. The opacity function is especially useful if you've created a layer that has to much contrast, as compared to the other layers. You can mute them down and blend your image much better.
Step 3: Airbrushing and Shading
One of the best features is the ability to pinch to zoom. This comes in, especially handy when you're trying to create fine lines and will help you compensate for the unwieldy nature of the stylus. A wiggly line, when drawn zoomed in, will appear perfectly straight when the image is zoomed out. Another tip, as mentioned before is to apply only light pressure on your stylus, and move quickly as you're drawing. A light, swift had will ensure a nice straight line.
There are few ways you can add color to your work. The first is simply using the fill tool. It does work, but I find you often have to clean up the edges, plus you may not get exactly the tone you're looking for. The second is airbrushing with an opacity of .75+. This is great for solid colors, such as the cloak in the V for Vendetta image, but wouldn't be as effective when used on the brick behind him. The only issue is with keeping inside of your lines. If you look at the outside edge of his cape, you can see a bit of over spray, however this is easily hidden by the layers above it. If the over spray ends up on a higher layer, it will show through your work. You can clean up your lines with the eraser tool since it only affects the layer you're working on.The third is layering with your airbrush. This is great for parts of the sketch that have many different shades and textures, like the background. This way can be a bit trickier, because as the color builds up, it can make 'blobs' of darker color, although, done right it can end up looking more realistic. A decent setting for layering would be around .02-.05 on the opacity. Unfortunately, there's not a lot of room on the opacity scale as anything above that tends to get dark very quickly, but with patience, you can work on the lowest settings, slowly layering up to the desired color.
I recommend creating a new 'higher' layer for your shading, especially over solid colors, such as V's cloak. That way, if you make any errors in the shade, you can erase that part of it without damaging the base color. When you're satisfied with your shading, you can merge it down. Shading should be done with a low opacity of somewhere around .01 to .00. Again, the opacity scale escalates quickly and anything higher than that would be too much.
Step 4: Tool Tips
There are two airbrushes available in both, the free and the paid version of Sketchbook, however, there are many other airbrush type textures that can be useful in your images. Don't limit yourself because it doesn't have an airbrush icon. In the Boondock image, the beard stubble was created using a tool that resembled blood splatter.
Modifying your Tools;
Beyond the radius and Opacity, your brushes can be modified to fit any coloring and texturing need. To the right of the 'last tool' button on the brushes menu, there is an icon that looks like two horizontal lines with a circle on each. These are your fine adjustments. It's difficult to tell you how you should set them, as it's a very personal thing, but one thing I like to do is set one brush to standard, 'solid' flow, and the other to a more textured flow with more noise, jitter and less squish.
You can blend your colors manually, or you can use the eye dropper tool to gather color information from the 'base' image. Just be aware that the sample area is pin point, so you'll have to work in shades. For that, I'd suggest on starting with the mid-tones then layering the lighter and darker colors over top.
When all is said and done, and you're ready to abandon your drawing (there's no such thing as complete), then it's time to delete the base image. You won't be needing it anymore. You also have the option of deleting your line layer, however you will need to make sure that your edges are nice and crisp otherwise your image will appear blurry. It's completely optional, however since having the lines is a matter of taste, and whether or not you're trying to create a photo realistic sketch. It's not necessary to merge your layers down since, when you convert to a viewable format, it will merge them down anyway.
Finally, you just need to convert your sketch into a viewable format. From the gallery, choose' share' then you can pick either png, jpg or psd formats. Personally, I usually save as jpg, but they all have their advantages and disadvantages.
That's it. I hope you found this instructable useful and if you have any questions, I'll try to answer them as best I can.
Thanks for following.