Probably the kind of thing "painter" would be used for, but heres what I do in photoshop.
This is very simple, but I've been asked a few times what precisely I did to get the look, so I thought I would share it.
Of course, while the technique is still simple, using it in practice takes time. Its not a filter or anything.
For each step I will provide the simple step, and then go into detail on some organization and details of my process for anyone who wants more detail. If you want the 20 second version, just read the parts above the separation line.
warning: This is intended for use with a graphic tablet (wacom in my case). You can try it with a mouse but I don't know many people who can do much digital painting with a mouse.
And I'll note that I am far from a professional, and merely have done some of this in my free time. I do not pretend to be an expert, just simply wanted to throw this out there.
The image below is a finished digital painting I made using this technique, although you cant see the purpose of the technique at this size. Read on for that.
Step 1: Place down base colors
But a quick warning first: do this at a very high resolution. The effect will be completely lost otherwise. It doesn't have to be this big, but the final image I showed you is 4200x2000 pixels at its full size. Just save it to a smaller size for the net later.
For this particular example I'm using a shirt sleeve that had a lot of detail in the wrinkles because it shows the effect well.
Because of the nature of the specific details of the area, I did not use my tablet for this part but instead just used the polygonal lasso tool to put down the shades. For more organic areas like arms and the face I paint out the shades/highlights with my tablet.
I've included an example of a base done with a tablet in the images.
I create a folder for each general color needed, in this case that includes folders for Blue (hat, undershirt, wristbands and such), Light grey (shirt), Brown(glove), and so on.
This technique needs to have a high level of contrast to work properly, so needs somewhat detailed shading. Small areas may be able to get away with the base color, one shading color and one highlight, but larger areas generally need two degrees of highlight and 2 degrees of shading, as well as pure black/pure white touch-ups.
In the case of the sleeve, I used a base color, one shade, and two degrees of highlighting. And then did a little more that I will detail in a later step.
Step 2: Blend the shading together
Using the smudge tool with a chalk brush at 75% strength, blend the shading together.
Select the smudge tool, which is in the set with the blur tool beneath the eraser. The shortcut is "r" once you have selected the smudge tool from that set.
Now the twist to the brush you use. With the smudge tool selected, click on the brush selection.
By clicking on the right arrow at the top-right of the brush section box, you will see a number of brush categories you can bring up.
Select "natural brushes 2", then click on the brush selection again and choose the second brush available (at least to me), which is the chalk dark brush 3.
Set the strength of the brush to 75%.
The brush size depends on how precise you need to be, try it at different sizes. Certainly not too small.
You will need some basic understanding of shading and lighting and art skills, but just use the brush to mix the shading together. Use it as you might a real brush, generally making strokes with it rather then holding it down the entire time.
Generally stroke away from the brightest highlights and darkest shadows so that you dont disrupt their edges very much. Otherwise you will end up mixing them into everything else.
I'm really just explaining a technique to get a specific look and not trying to teach you how to digitally paint, so thats all the detail I will go into there.
Remember how I made many layers for each color? Well that was so that I could more easily edit the various layers and their opacity before i do any blending.
I usually put all the folders for the colors into one master folder, than duplicate that before doing the shading as a backup so that if something goes wrong I can just redo it; although of course I also create many snapshots or saved copies as well. Anyway, then merge each colors folder so that all the shading is on one layer so you can blend them better. You may want to leave your brightest/darkest shades and highlights on their own layers and add them in later so they don't just get mixed into the rest and get lost.
Ive included a screencap of the brush just in case.
I also spent 5 minutes recreating the steps of this tutorial on a quick patch of blue for no particular reason.
Step 3: Sharpen the image
Using the chalk brush helps to blend your image together in a fashion somewhat similar to painting, but is not very clear.
To bring out the effect, sharpen the image using filter > sharpen or filter > more sharpen.
I sharpen each area individually as its imprecise and depends on resolution and other factors for what looks like. Typically what I will do for the resolution I work at is one "more sharpen" and then a normal sharpen or sharpen image. If you do too much the image will get grainy and ugly. It requires some trial and error.
I zoomed in on the top of the sleeve so that you could see the effect in more detail, its lost at the smaller size.
Step 4: Examples and Tips
But hopefully photoshop users glancing over this can at least take something from it they can apply in some way.
After Ive done everything I described, I always go back and add another layer of shading/highlights to add some contrast and overall lighting that I may lose when concentrating on details.
Using the layer mode options beneath the "layer" tab, set to normal by default, I typically create a layer set to overlay for highlights and another for shading. I will then paint some more shading onto the image by painting black on the shading layer, white on the highlight layer, and then doing the same chalk smear effect onto that shading I did while creating the base to keep the look consistent.
Then adjust the opacity for each layer, as 100% will often be too much.
This is just an easier way to touch up how you want the image to look and add more contrast without having to make 8 different colors of shading and highlights for everything. When doing so much detail the larger lighting can get lost, and this is how i address that.
In the images below Ill include examples of the digital paintings I've done like this. Yes, obviously im a big baseball fan. I do very few of these types of paintings, I'm an art student but not for illustration. I do have large printouts of all of these signed by the players involved, which is cool.
For the sake of the tutorial I enlarged parts of each to show some detail in the small images allowed on instructables.
I'll note I did the two included in about 1/3 the time as the one featured in the tutorial, which took a very long time, as its far far more detailed.
This is my first attempt at making an instructable, so any feedback is appreciated! Although I realize this is probably something more suited for a specific photoshop website, I'm an instructables fan and its the only site I know of that has such a good interface for creating tutorials so I decided I could spare some time to try it.