Today, I'm going to show you how to take a regular 3D image of a brain and make it look like an MRI of a brain with Alzheimer's.

I'm going to open my image 'brain' up here and we can get started!

First, we're going to create several copies of the image. We need to make four different copies.

This way, there's a total of 5 layers. They should be labeled, from bottom to top: Bottom, Green, Purple, Orange, and Blue.

So while I continue to label these, I'll go ahead and tell you the use of this.

The goal here is to better educate people about the affects of Alzheimer's on the brain, and where precisely it affects the most.

So Green means that the brain is healthy, Blue is slow deterioration,

Purple is more rapid deterioration, Orange is critical, and Red is failing.

I forgot to add in the Red at first, but I do so later... if you want, you can duplicate the background layer to have another layer titled Red.

So now we're going to begin the actual editing. Go to Image and then Adjustments, and we're going to focus on Hue and Saturation.

Remember to hide the rest of your layers while you do this, so you only see the layer you're working on.

Now, go back to Hue and Saturation. For a very vibrant green color, you're going to want to stay on the master section.

Start by moving the Hue slider to about +100, give or take 5.

Move the Saturation slider all the way to +100, and move the Lightness slider to -13

Click "Okay"

Hide the Green Layer, and move to the Purple Layer.

Make sure to click on the actual image, like I didn't...

Again, we're going to the Hue and Saturation tab under Image Adjustments. For this, click on the Master drop down, and choose Reds from the list.

Change the Red Hues slider to about -93, the Saturation slide between +40 and +50, and the Lightness to -3.

As you can see, our project is coming along quite nicely already.

After this, we're going to move on to the Orange Layer.

Again, we're going to the Hue and Saturation tab under Image Adjustments

Now for this layer I want a really bright orange, so I'm going to stay on the master list to begin with.

I played around with it a little until there was a color I liked. I put hue at +33, saturation at +66, and left lightness at 0

Now I'm going to the Reds tab to help me get that real orangey color I want.

I set hue at -24 and left everything else alone.

Lastly in color adjustments (for now), I'm gonna work on the Blue layer. Make sure you're only focusing on that layer, hiding the others.

Back to Images, Adjustments, and Hue and Saturation.

I'm going to stay on the Master tab for now, to help me get that Blue color that I need. I set hue to -180

Now I'm going to go to the Blues dropdown, and set the Hue on that to about +39 even though it doesn't do much.

I'm gonna switch to the Reds dropdown here, setting the hue to -16 so that it's a very nice, bright blue.

So after this, I'm going to go through and make sure all of my layers are no longer hidden.

Now, we're going to go up to the top, choose the Layer dropdown, down to Layer Mask, and apply the "Hide All" Layer mask to all of the altered layers.

So the Green, Purple, Orange and Blue layers.

Now, the reason we've added the layer mask to the Green layer even though it's technically our base, is because we want to maintain that pristine white background.

Select the Green layer Layer Mask as your current canvas, and then click on your paintbrush tool.

You're going to color the whole brain area in so that the Green shows through. Make sure to paint on the actual layer mask, not the layer itself.

Be mindful of the edges, we don't want them to be greyish.

Color, color, color! Leave no holes and stay in the lines!

Suggestion: don't try to color it all in one click, you'll mess up and have to start all over again

Color, color, color! Continue coloring! You could use a bigger brush, but I prefer not to I find that

Sometimes they get sloppy.

Now that that's done, we're going to begin to work on the purple layer.

Make sure to select the Purple layer's Layer Mask, not the layer itself.

I'm making this brush a little bit smaller (about 10px), because we're going to just work on the very edges of the brain here.

Personally, I prefer to zoom in (if I could find the tool!), so that I can be more precise.

Gotta move it so it's in the spot I want.

Now, select your paintbrush tool and begin to outline the edges of the brain!

Well, as you can see, I forgot to do what I told you do to, which was not paint on the layer itself...

Gotta try to fix this...

Hide other layers...disable layer mask... make sure I didn't actually move the image... erase paint.

Didn't actually paint on the brain, so not even gonna bother erasing the paint, instead I'm just gonna move the brain to where it should be.

Try number two!

Paintbrush and layer mask!

So, we're only gonna outline the very edges of the brain, going about half an inch in (on my screen at least)

On this, we don't have to be so careful about the edges, because we didn't darken the purple layer.

Color the brainstem purple too (that's the weird shape at the bottom right of the brain).

I figure this part is pretty self explanitory and I don't need to keep captioning this, so do your outlining and I'll be back shortly!

Okay, now that we've finished that, we're going to select the Blue Layer Mask to work on.

Here I'm going to move the blue layer down below the Orange layer because it makes more sense to me.

Again, this brush is going to be smaller than the last one we used. I set it at 15

You want to trace around the brain like you did with the purple, but trace inside of the purple.

It's okay if the blue overlaps the purple, we can fix that later by moving the blue layer so that it's below the purple.

I went ahead and did that, but you can do it at any time you please.

I'm not going to walk you through how to outline something; just make sure you do a complete outline of the brain inside the purple.

So here's where I add in the Red layer that I'd forgotten about earlier. I duplicate the background image, and then go to Image, Adjustments, Hue and Saturation. I set it under the Orange layer.

Stay on the Master option in Hue and Saturation, and go directly to the Saturation slider. I set the saturation to +99

Now go to the Reds option on the drop down menu, and set the hue to about -23 to get a very vibrant, deep red.

Now, go to the Layer tab, and add a Hide All layer mask to the Red layer we just created.

With the red, you want to focus on the center and front of the brain, which is where most deterioration happens.

That being said, each person with Alzheimer's is different, so there's no need to be super specific about placing.

I would suggest including at least one patch of red in each third of the brain, depending on how severely you want the brain to be afflicted.

As you can see, I'm trying to be very precise and stay within a specific ridge of the brain. This makes it look more realistic.

If you're like me, and precision isn't always your strong suit, feel free to zoom in and shrink your brush even more.

Or, you can use your eraser on places that you feel as though you went out of the lines.

I utilize both here, zooming in and erasing.

In the next part of this tutorial, we'll finish this brain up!