Gimp: Using a Layer Mask

hello today I'm going to show you how to use to take this poor defenseless bunny and put it in the cup of scalding hot coffee you start off with this picture of the bunny and the cup you put them together and you use a layer mask to mask off the bottom of the bun the layer mask is a very important tool in maybe one of the most important tools so I'm going to start off with my source image this is just a stock coffee cup is my background and I'm going to open as layers so that the file I open will be created on a new layer there now I have two layers you can see in my layers dialog and the next step is to take the yellow off of the bunny the easiest way to do this is they use a fuzzy select tool make sure your threshold is at a good number and select the yellow and hit delete control shift a selects none and it looks like when I deleted the yellow background it deleted it to be my background color the reason it did this is because my layer does not have an alpha Channel if I had an alpha channel it would delete it to transparency that's what I want so I'm going to undo all that right-click on my bunny layer add an alpha Channel you notice it it's still selected back here and let's hit delete again there you can see the checkerboard over here in the layers dialog and you can see through the yellow now is deleted it is gone control shift de selects none and a view show layer boundary so that yellow outline of my layer is gone now I can move my bunny around let's move it up here and put it in the fire scalding hot coffee and you'll notice that it looks like my Bunny's head is cut off that's because it is off of the canvas the canvas is only so big and the bunny is not fitting on but fix this I'm going to go up to image and fit my canvas to all the layers there now the canvas is bigger but you notice that you have this checkerboard up here that's not white I want that white just like down here so I could try to go to my paint bucket and paint on white but no go is not painting anything on I'm going to go up here and show my layer boundaries again that's the boundary for my bunny and this is the boundary for this coffee cup layer see how even though my canvas is big enough this coffee cup layer is not big enough to paint on I was trying to paint off into nothingness I need to actually make my coffee cup layer bigger as well so it takes up the whole background I can go to image now go to layer and make my layer the image size that is going to expand the coffee cup layer to fill up the entire canvas and you'll notice the layer boundary is now larger and it added background color to fill up the transparent spots I'm just going to paint on one I fixed it now I need to get rid of the bunnies feet so that it looks like it's in the coffee I could use my eraser tool but if I used that everything that I erased would be destroyed forever and then if I decided I wanted to go back or if I erased a little bit too much I would have to undo it it just wouldn't work as well so using a layer mask is better you're not destroying information with a layer mask you're actually adding more information you're telling certain parts of your layer that you want them to be transparent let me show you how it works first select the layer that you want to add the mask to you right click add layer mask and then it gives you some options white full opacity means that you leave your layer opaque your bunny is still visible if you choose black it makes your entire bunny transparent so your bunny will look like it disappears you could choose selection say I had a part of my bunny already selected using the fuzzy select tool or one of my other selection tools that would mask off just what I had selected already for now I want to leave my bunny completely visible white now I'm going to paint on black to make certain parts of my bunny transparent see how that works notice I'm painting on to the layer mask over here in the layer dialog when I added a layer mask it gave me a second box right beside my bunny if you have selected the left see how there's a white box around it you've selected there and you go painting it's going to paint black all over your bunny that's not what you want you want to paint onto the mask so I just undid that the nice thing about a layer mask is if you decide you want to paint the bunny back you can paint white onto your mask and here she is again this is great when you do in detail work so let's get the result that we wanted hanging on black get rid of the bunnies feet I'm going to go up here into the coffee and there we have it that's just quick not the best result you can play around with the brushes - it's just like you're painting white or black onto a layer this layer mask use a fuzzy brush the edges don't look so hard so there you have it that's how you use a layer mask you can take your time on your bunny and make it look as realistic as you want the steps that you would want to pay particular attention to are when you're painting onto the mask here and also when you're selecting your yellow with a fuzzy select tool we'll make sure your threshold is a good number that gets rid of all the yellow but isn't so high that it starts to get rid of some of the bunny as well hope this helps

Channel: CCS Computer Class

Views: 45,297

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Id: PI8_2FnIow0

Length: 8min 16sec (496 seconds)

Published: Tue Oct 01 2013