Preserved Topic: is there a difference??

Hello all...
i was just wondering if there is a difference from using a layer mask/channel mask and just using the layer/channel? I know in the masks you can do stuff but it's not permanant, but is that the only difference?? can i do everying in the layer/channel as in their masks but it's permanant??

Fraz...

Yah, if you use some black in a layer mask, you'll make that part appear as deleted. But! It's still there. Now you can apply white and "un" erase pieces too. You can also use Quick Masks, which are kind of like some short cut mixing both channels and masks. The mask works as a quick channel which you can paint and draw on in black, it appears red. Then you pull away from your QM and it's a selection, much like if you had created a channel and then selected it. Did any of that make sense?

Your pal, -doc-

lets get the terminology straight.

A channel is not a layer. An image contains channels which when composited together make up the total. Depending on the colour space chosen depends on teh number and types of channel.

RGB - 3 channels - red, green, blue
CMYK - 4 channels - cyan, magenta, yellow, and black
LAB MODE - 3 channels - lightness channel, 'a' channel and 'b' channel
GRAYSCALE - 1 channel - black

Channels are what carry the pixel information for the image.

Layers on the other hand are what separates different elements that are contained in an image. Instead of drawing everything on a single sheet of paper, layering a document allows us to draw elements on separate sections or sheets of paper, that when are laid upon each other constitute the 'whole picture'.

Now a Layer Mask is a separate entity that can be added to a layer to hide/reveal part of that layer. A layer mask uses only Black, white and shades of grey to either reveal/hide a layers contents, by paiinting on the layer mask with any of the painting tools.

An Alpha channel is not a layer mask. It is used to store and/or create a selection. The alpha channel can be copied and used to create a layer mask, but they are not the same thing.

Quick masks are a visual way of 'painting' a selection. When in quick mask mode, one can paint a selection using any of the paint tools. Quick masks are temporary and only exist when one is in the quick mask mode.

In summation,

channels hold all the image data, the pixel data, control the brightness values of pixels
layers seperate image elements (for ease of manipulation)
layer masks are layer dependant and hide/reveal areas of a layer
alpha channels store selections
Quick masks is a temporary state used to paint selections (visualization aid)

edit: almost forgot! Welcome to the ASylum Crimson!

~Vp~



[This message has been edited by vogonpoet (edited 08-20-2001).]

Thanks loads VP . . . That was a very informative post, ( for me anyway )! Have a good one . . . Mark.

Kruzr?! Where the Hell have you been? Are you sticking around or is this just a cameo? California? When did that happen? What's going on around here?

Hello...

Thank you all for helping me out.

Doc that made complete sense and vogonpoet, what i meant was layer and channel instead of layer or channel. Sorry for misleading you, but still your summary really helped me understand better.....

i am still a little confused though... I made a cicle in a new layer and saved it to an alpha channel. In that channel i selected the layer and put gaussian blur on it.. and then i went back to layer and used the lighting effect on the circle with the channel circle as my texture channel... the effect was very nice. but when i applied the gaussian blur to the layer circle and applied the lighting effect.. it gave me a different result.... why is it doing this ?? considering the alpha channel is white within the circle, doesn't that mean the selection is competely visible just like like the layer?? i'm sorry for the confusion...... but i wish to master these techniques if i'm gonna build it as a career...
thanks for the welcome...

Fraz...

The channel you use for lighting effects is not used for hiding and revealing things, but just for the height map for the lighting effects. The 'map' is pretty simple; black parts are low parts of the picture, and white parts are high parts.

so in this example:

The top part is the alpha channel used, and the other part is what you get when you run lighting effects on it. the white spot appears as a bump (since it's higher than the gray backround) and the black spot as a hole. I've added a clouds pattern on the right to show how it works.


Taking no sides in the neverending battle between Good and Evil. However, I do need more popcorn.

Hello...

Ohhhhhhh......well that explains it, thanks mahjqa.

Fraz...

hey! I actually understood all these posts

thank you, I still needed to learn my something new for the day...
now I can go to sleep complete

...penny

hehehe, i saw this post, and i couldn't help it....

"Hey guy! check this!" this support a little what VP just said about Channels.
Some day somebody from here will help me to translate to real english....


.-rotate script by Mr.Max

[This message has been edited by Wakkos (edited 08-21-2001).]