Tutorials

Adding Alpha & Transparency Using GIMP

by RPGking (PM)

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Current Language: English
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FOREWORD & COMMONLY ASKED QUESTIONS

Many users here on 001 ask how to make transparency or semi-transparency for their effects, tilesets, etc. Before I show you how to do this, lets go over some commonly asked questions by the community.

  Firstly, can transparency be added within MS Paint, the answer is no. The only transparency that can be added in MS Paint is the magneta, magic pink. Even then that can only be used within 001.

Secondly, what format should it be saved in. Images with transparency or semi-transparency should always be saved in PNG format.

Thirdly, what programs should I use. You can use any variety of programs, I use GIMP for all that. www.gimp.org

GIMP is basically the free version of free alternative to the expensive and pay to get Photoshop.

 

LAYERS

Layers are a must for this type of work. In GIMP, the layers window should open up by default with any new document. But if it doesn't, heres where to get them to show up.

1. On the top right of the screen in GIMP, you will see a Windows tab. Open it.

2. You will see another tab in the drop down menu that says Dockable Dialogs,

3. In the drop down menu that just showed up you'll see Layers, click it and the window will show up.

Alternatively, you can use Ctrl+L to open the Layers window.

THE LAYERS WINDOW

When the Layers window comes up it can be quite confusing at first, there are so many buttons and bars. I'll take you step by step through it and explain how it works. The definitions underlined are the things that we will use.

This is the layers window, and how it should look when you open it up on a blank document. Now lets go through what these icons and sliders mean going from the top down.

Layers (w) The Arrow: All this does is configure the tab which you shouldn't need to do.

Mode: Layers modes that can be used, but we won't need this.

Opacity: How transparent the current layer is. The sliders default setting is 100.0, which means the image is solid. ( note if your image has transparency, then it will have a grey checkered grid behind it. The more transparent the more visible the checkered grid.)

Lock: Locks all alpha and transparency for the chosen layer.

Just under Lock is a thumbnail of the current image and an eye. The eye will hide the images or whatever is on the selected layer. You'll also notice a chain icon next to the eyeball when you have more than one layer, this allows the selected layer to lock itself so no changed can be made to it. This can be toggled.

Paper Icon: New Layer.

Up/Down Arrows: Changes the layers place in the layer stack. We won't need this though.

Photo's Icon: Creates a duplicate layer.

Anchor: Anchors a floating layer, but we won't need this.

Trashbin Icon: Deletes a selected layer.

LETS GET STARTED

Without further ado lets do this thing! For this tutorial and by request, we will be doing a side-scroller water tile. It will be semi-transparent meaning you'll be able to see the character under it.

1. Open GIMP, go to File> New> Create a new document that is 32x32.

2. Create the document and open the Layers Window using either Ctrl+L or the other method described above.

3. Create a New Layer via the paper icon at the bottom left of the Layers window (for further reference see the section above or the picture).

4. Input all that you see into the New Layer window using the picture as a reference. Make your window resemble the picture.

 

5. Click OK and hover your mouse over the box where your new layer is in the Layers Window, hover your mouse over to the right of the eye and a blank box will appear, click it and a Chain Icon should appear on it. This means the layer is locked and we cannot edit it. Look at the picture below for reference.

 

6. In the Layers Window select your Background Layer, and make your water tile. DO NOT add Magic Pink or Magneta to it. My water tile is below. It is basic but it'll do.

7. Now, go back to your layers window and for the Background Layer, move the slider to the desired opacity. I set mine to 75.0. When you do this you will notice the checkered pattern mention above behind your image. Heres what it should look like.

8. Now select the layer you made previously and unlock it. You'll notice that you still have the chunk of white on your water. This isn't good. Theres many ways to get rid of it but I want to familiarize you with a more complex but effective way to do this. Lock your Transparency Layer again, and at the top right go to. Layer > Transparency > Color to Alpha. Click it. Heres what you should see.

 

The color to switch to alpha always defaults to white. If your background color isn't white, change it to that color. Then click OK.

9. Unlock your Transparency Layer, and then go to Save As. Choose your desktop (or where ever you want it), give it a filename and at the last letter or number of your filename, type .png 

After you do this a window will come up with 4 options, click on Export, then when the next window comes up click OK. The options and values in those windows aren't important unless your a professional or know what your doing with them.

10. Import your new .PNG water tile into 001 and test it out. This method of adding transparency can be done to anything or applied to anything.

Enjoy and walk away with new-found knowledge. :D

 

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