What are selections and transparent layers?

I am trying to apply a filter effect to an image and am getting an error message along the lines of

This filter can only be applied to a selection or a transperant layer.

Can some one explain to me briefly or point me to a good tutorial on what selections and transperant layers are?

I tried to go Select>All to place a selection marquee around the image. Thje filter would then work but it seemed to apply the filter to the background behind the image not to the image itself. In other words if I moved the image down slightly I could see the filter effect applied to the top part of the canvas behind the image.

I also do not quite understand what transperant layers or selections are. Any tutorilas on this would be great.

Thanks in advance.

Trueman.

Photoshop has the wonderful ability to allow images in the PSD file format to have layers. Layers are just as they sound, various layers creating an image. By clicking "Window/Layers" the Layers palette will be shown. Note, the Layers palette is shown by default in Photoshop. For example, if you have an image with a solid blue background, then add text to the image, the text will be on a seperate layer than the blue background. This allows you to make changes to the blue background layer without affecting the text.

Another important part of Photoshop is the History palette (shown by default). This allows you to preview changes made throughout the entire process of the image being created.

Photoshop can be a complicated program, but an extremely useful tool to anyone who is willing to do a little homework. I highly recommending going to your local bookstore and purchasing a "Photoshop Guide." I recommend a series called "Visually learn...." They provide a well layed out book with full color images to make the learning process as simple as possible. Good luck with your learning of the greatest program for the computer.

Included is an image to help you with your questions and this post. Feel free to send me a private message if it confuses you in anyway, or if you have a few more questions. However, the best way to learn is to click away.

Note: Image is about 130k, so be patient for the download if your using dial-up.

Frith,

Thanks for the reply. I should have said that I do have a basic understanding of layers and how they work. However I do not understand the error message I am getting when I try to apply a filter.

the message is

This filter requires a selection or a layer with transperancy.

What exactly are they talking about here?

Certain filtes cannot be used on a transparent layer. There has to be some sort of selection for them to work. A Layer that is partly transparent, but has something in it is acceptable too, but just a blank transparent unselected layer will not work for some filters.

Thanks Frith,

I understand now.

Trueman