| A quick explanation first, I am a webmaster in training and
while I was trying to learn about alpha channels, in Adobe Photoshop 5.5,
I could find very little about Alpha channels, although there are many
good general Photoshop tutorials. So I decided to quickly knock this page up. I hope it is useful to you. If not then let me know either by Email or via the forum at the bottom of this page. |
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Click on the image to the left to go to the Webmonkey tutorials Site. I have found no end of valuable tutorials there on all sorts of web design subjects and products. It is well worth bookmarking their site for future reference. | ||||||||||||||||||||||
| In order to understand Alpha channels, you must first understand what a channel is. I will try to explain this by using an image in Photoshop that is being displayed in RGB mode. | |||||||||||||||||||||||
| As soon as you open any RGB image, there are already 4 channels in the image. They are the "R"ed channel, "G"reen channel and , yes you guessed, the "B"lue channel. The fourth is a composite of all 3 which allows you to view just one of the individual colours or any combination of all 3. |
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| These channel's store the colour information for each individual pixel & are produced automatically by Photoshop. The kind of information stored is, how each colour should react with the other colour's in the pixel in order to produce the required effect in whatever media the image is to be viewed. | |||||||||||||||||||||||
| As well as the standard 4 channels Photoshop will also support images with up to 20 more channels. These are the mysterious Alpha Channels |  |
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The Alpha channels are basically templates for a selection that you have set up in an image. The difference between a normal selection and an alpha channel selection is the ability to save and copy, the selection, across to other images. | ||||||||||||||||||||||
| A brief tutorial on how to save a selection as an Alpha channel can be found by clicking on the image to the right. |  |
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| So to summarise, Using Alpha channels to save a selection allows you to set up a very complicated selection and use it over again. As long as the original image, that an alpha channel was set up in, is open. The selection can also be copied across into another image. This benefit can be very useful in altering images to appear as natural as possible. | |||||||||||||||||||||||
| I have a forum set up for you to post comments or questions regarding this site or Alpha channels. Just click on the link to go to the Forum | |||||||||||||||||||||||