I use a Wacom 3 tablet, but as far as I know everything explained here can be done just as well with a mouse.
Images used and some brush settings included at the end.
;3; please forgive and spelling or puncuation errors!
I circled the head with the Lasso Tool. In the screencap the setting for the Lasso had feather at 10. that's a mistake (just incase anyone noticed XD) the feather should be set to 0.
some people set the lasso tool to feather 2-3 and closely outline the head. this works pretty well, but it's very time consuming. step two kind of elminates the need to do this.
After step 1 I copied the head and pasted into a new image. From there I zoomed in to begin erasing the background using the Eraser Tool set on Brush. Pictured here the zoom is only about 100% since this was a large image to begin with that was ok. On a smaller image you will probably have to zoom in to 200% or more. Also most people like to set the eraser's opacity low when they erase. I find that by going slowly and zooming in very close, you don't have to do that, so I left the opacity at 100%.
Here's the finished product from Step 2. I then Select All and copy the head into the Drew Fuller Image.
I <3 the Free Transform Tool! :3
I stumbled upon this tool while just messing around with things to see how they work. It is phenominal for resizing/stretching selections. you can even get away with resizing up tiny images without losing that much image quality most of the time. and :DDD you can tilt/swivel the things you've selected.
You have to be careful though, if you just make a selection willynilly it will keep to the selection when you tilt or stretch. I've found that by making a large selection with the Rectangle Tool then switching to the Move Tool and tapping an arrow key on the keyboard you can force selections find the edges of whatever you've selected. The option to free transform only appears when you have the Rectangle Tool or something like that on though, so don't forget to switch back.
You also have to hold down the Shift key while you resize in Free Transform otherwise the image will lose its correct proportions.
Here's the Free Transform after I've got it about where i want it. I eyeballed this a lot going back and forth with diff sizes and degrees of tilt. Once you finish the Free Transform you can go back and do it again if things don't match up.
Sometimes it also helps to lower the oppacity of the layer the head is in and see if the features of the face match up with the original image. This doesn't always work if your heads aren't in the exact same position. I've found it easier to check out other pictures of James Marsters and try to see if the head is the correct size in proportion with his chest or shoulders.
There is a lot of yellow in the Drew Fuller image. I've found that yellows in a picture are best matched by adjusting Green and Red.
You really have to play around with curves till you get things right.
More color managment. This time with Color Balance.
I'm trying to get rid of the red tones to better match the body here.
Still trying to get rid of the red.
Time for the Smudge Tool! If you look at the Layers window you can see that i have a few copies of the Drew Fuller image in there. That's so that I always have a unaltered copy should I mess up. :'D
Using one of these layers I smudged Drew's hair underneath James' head.
More Smudging. This time on the layer with James' head. I want to soften the jaw line so that the head matches the neck better.
I don't know if i mentioned it before, but I've got the Smudge Tool Strength set at about 60. This setting works kind of like the Opacity does for the Brush or Eraser. Experiment with that setting till you find one that works for you.
The shadow on the back of the head and jaw is a little too dark. Here I'm using the Eraser set on Brush with a low opacity (about 35). Also notice that I've increased the size of the eraser.
I want to soften the edges of the head and jaw even more so that they blend better with the neck and background.
The head is still a little too glossy and doesn't match with the body as well as i want.
Here I'm adjusting the Brightness/Contrast to dull the head to better match the body.
Really just repeating what I did Step 12.
Adding Noise. This is a trick that works well with Black and White images, but sometimes it works with a full color one as well.
I never add Noise more then 4 strong. Anymore then that and your image will look poorly compressed.
The Finished Product!
Make a new Layer and select a nice shade of Blue.
Using the Brush Tool size 4 i colored the Blue in the new layer over the eyes.
Then Erase the parts of the Blue that over lapped the eyelids.
Set the Layer with the Blue to Overlay. You can play with the different filters here to achieve a look you like. I want to make the eyes bright so i used Overlay, but the filter Color would have worked as well for a more natural look.
Using the Dodge Tool, size 5, Exposure 10 on Highlights follow the natural light hitting the lower lip until you achieve the brightness you like.
without eyes and lips
with eyes and lips
When I first started using photoshop my main problem was sucky brush settings. So I've included some screencaps of my settings.
I mainly use these settings for real drawing, but i've found that they work pretty well with manips too.