[Award Winner] Explanation of Layer Masks in GIMP(and PS)

[Jkaen]

I can confirm the video is viewable

I find mask really useful, and I tend to have them on most layers to be honest, what I really wish was that you could have 2 or more active masks on a single layer at a time (ie a blurred forest mask and the landmass mask). And hence not be forced to apply a mask when not ready to.

[bryguy]

viewable on my mac, but it goes off the screen

[Karro]

I can confirm the video is viewable

I find mask really useful, and I tend to have them on most layers to be honest, what I really wish was that you could have 2 or more active masks on a single layer at a time (ie a blurred forest mask and the landmass mask). And hence not be forced to apply a mask when not ready to.

QFT

They are very nice tools... but I have found myself wishing that a couple of times, as well... I have hated having to apply the mask, thereby forcing any changes to be made permanent (short of a ctrl-z).

[mmmmmpig]

I too was able to view it, but it seemed to go off the screen for me as well

[jfrazierjr]

This next video is longer and larger in size, but smaller in screen real estate as I constrain the video to a portion of the screen indeed of full screen. Link is here. Note, the previous step and this step can be skipped if you already have a method for generating water that you like or if you have an existing texture. This is included here for completeness.

In this video, I finish up the water using these step:

• Create a new layer named Water Texture
• Create a new layer named Water Texture Overlay
• Fill the Water Texture Overlay layer with 50% gray, which is 808080 in hex as per the video
• Run the Filters->Render-Clouds->Plasma set to max turbulence on the Water Texture layer
• Set you Foreground to black and background to white and Run Colors->Map->Gradient Map on the Water Texture layer
• Turn off the Water Texture layer so it is not visible
• Select the Water Texture Overlay layer and run the Filters->Map->Bump Map with the Bump map set to the Water Texture layer. Make sure the Elevation is turned all the way up as high as it will go. Set Depth down around 10-20 as you prefer.
• Change the Water Texture Overlay blending mode to Overlay and you should have an image of blue with a very choppy texture over top.

[jfrazierjr]

Ok.. up next, we get to the real meat of the tutorial show you how to actually use a layer mask. Now, remember from the previous posts that when painting on a layer mask, that black is opaque and white is transparent.

• We start by creating a new layer for the bank of our stream.
• Fill this new layer with an appropriate texture, in this case, I used Gravel_blu-aT.png from the CSUAC (which is where the rest of the textures come from).
• Next, we Add a layer mask to the gravel layer, in this case, I have chosen white so that nothing shows through.
• Select a largish brush, perhaps cranking up the multiplier some and select your foreground color to white.
• Now, making sure you have the Layer mask selected in the Layers dialog(it has to have a slight white halo around it, though it may be hard to tell since the mask is white!) Begin carving out the rock texture using your brush to reveal the water underneath.
• Just to show the technique, once I finish my main shape, I switch to a smaller brush and back to white and draw in a small island shape.

You should have something like this image


Not to very exiting is it eh? The banks are "hard" the water appear the same depth every where, and the rocky texture is just way overpowering over that much space right? Don't worry, we will fix those issues very shortly.

[jfrazierjr]

Here is the next video.


Now, we will clean this up a bit and make it a bit prettier.

• Start by selecting a med/small brush
• Set the foreground color to 50% gray (808080)
• Now, trace over the edges of the creak walls on the layer mask for the Rocky Bank layer. You don't have to be perfectly symmetrical (and should not!), nor do you have to trace every single square inch. Notice in the video that I left some gaps and did NOT put down some grey in a few places.
• Finally, Apply a Gaussian Blur of perhaps 50 px. You can use less or more as your taste suites you.

Also, note that you could just as easily used multiple shades of grey on the mask layer. Perhaps Black, 80% gray, 50% grey, 30% grey, and white. This is all up to you as to how much you want the blending. The blur will do some of the blending for you, but with multiple greyscale passes in various places, this gives you much finer control over the final product. I did not feel like spending a ton of time on it, which is why I only did one single extra shade of gray in addition to the base black and white.

Here is what I have now, and yours should look something like this:


Hmm.. now this is looking much better. The water appears to get "shallower" in near the banks and in a few places, there are even some small pools of the stream. But UGH. the repeating rocky texture is killing my eyes you say! Fear not... we shall tone that down in just a few minutes. Stay tuned for the next exciting episode of "Playing with Layer Masks".

[jfrazierjr]

Ok. Yet another small update.

Ok, so in this episode, we will use the exact same technique to add some ground cover.

• Create a new layer
• Add a texture to the layer, in this case, I am using Grass_mud_jhd.bmp, again from the CSUAC.
• Add a layer mask set to White
• Change the layer opacity down to around 50% so you can see the lower layer
• Select the new layer mask you just created in the layers dialog
• Using a med/large brush Pencil set to black, draw out the river and parts of the bank in whatever pattern you wish to show
• Turn the opacity back to 100%
• With the layer mask still selected, Filters->Gaussian Blur around 50px, more or less to taste.

This produces something like the below image:

Now, we are starting to see something that looks like a creek bed in the wilderness. Next, we will add a tree texture with something like palm fronds.

[Absinth]

Great tutorial! Very helpful! Thanks for giving advice to the newless cluebies!

[jfrazierjr]

Great tutorial! Very helpful! Thanks for giving advice to the newless cluebies!

Well, thanks! You won't be a newbie for long. I started playing around in GIMP less than 5 months ago and most of what I know is due to many of the great people here and a bit of playing.