Using Eraser incorrectly?

[Raymee]

I've had CS3 for several months now, and have been practicing with it nearly every evening for a few hours. Invested in the the Total Training and refer to it and other training vids from Adobe & lynda as I work on my simple projects. It might take all evening, but between the vids and the help library I figure the tools out bit by bit and my knowledge of Illustrator has been improving well.

But..., the eraser tool seems to evade my ability to understand it properly. The reference material makes me believe I must be making some very basic mistake that I have been unable to pin down.

Is there is a difference between erasing shapes created in Illy and erasing parts of a downloaded file?

Example; I have recently been practicing changing up downloaded public domain illustrations (saw the Layers Tutorial). While I can use the eraser tool to modify shapes I've made from scratch, I can't seem to make it erase the same way with a downloaded picture. It either won't engage the tool (I've come to hate that "bonk" sound) or (after vectoring) will engage the tool, erases what I click and drag but then the erased lines re-appear when I release the mouse button.

I know it must be something simple. Could someone explain how do this? Thanks in advance for taking the time to respond.

[Scott Weichert]

The eraser tool will not function on raster images.

Chances are your "downloaded" images are jpgs or gifs, both raster formats.

[GuyB]

Hi Raymee,

Like Scott said, the eraser tool does not work on bitmap images, only on vector paths. And it is not very "evident" to use as you have to drag along the lenght of the path. Here is what the Help says :

«The Erase tool lets you remove a portion of a path. You can use the Erase tool on any kind of path (including brushed paths), but not on text or meshes.

To use the Erase tool:

If the path to erase is not selected, select it with the Selection tool . Or Ctrl-click (Windows) or Command-click (Mac OS) the path to select it.
Select the Erase tool .
Drag the tool along the length of the path segment you want to erase (not across the path). For best results, use a single, smooth, dragging motion.
Anchor points are added to the ends of the new paths.»

[The Repro Kid]

But the real deal is, the eraser tool, like the lasso tool, are two tools that in Illustrator, never should have been. they are superfluous to Illustrator.

superfluous |soōˈpərfləwəs|
adjective
unnecessary, esp. through being more than enough : the purchaser should avoid asking for superfluous information.
DERIVATIVES
superfluously |suˈpərfləwəsli| adverb
superfluousness |suˈpərfləwəsnəs| noun
ORIGIN late Middle English : from Latin superfluus, from super- ‘over’ + fluere ‘to flow.’

[Scott Weichert]

Oh, I disagree. The eraser tool is an absolutely great feature and is invaluable for creating artwork in some styles.

The lasso tool, I agree with you on that one. I've never touched it. There's no need. Same for the magic wand.

[The Repro Kid]

I think it's funny that the key command to call up the magic wand is "y." I think the Illustrator team must have a sense of humor. :)

[Scott Weichert]

I think some things are done to make the transition to Adobe apps easier for new users. That's why there's a lasso and magic wand tool in Illustrator - because Photoshop has them. Same reason Indesign and a frame and a rectangle tool, even though one or the other is all you need... because Xpress has them.

And they do have a sense of humor.. Mordy's phone number in the app :)

[The Repro Kid]

No, QuarkXpress does not have a rectangle tool. It never has :confused:

As interesting as Mordy's phone number sounds, I usually set my illustrator to show the moon phases. :cool:

[Scott Weichert]

Right.. the frame tool in ID was put there specifically for Xpress users so they would be less confused.

I generally prefer the moon phases too :)

[Raymee]

Thanks for the responses and suggestions. Scott and Guy, appreciate the explainations, basic as they may seem for those that better understand CS3.

Thanks especially to GuyB for the further clairifications as it got me looking in the right places in the reference material. I see I needed to go a step farther, and the importance of how the paths are treated by the tool. Grateful for the insights!

[Lukas Engqvist]

You can actually "erase" from a photograph (raster image) non destructively, by using layer masks.
A layer mask in illustrator is a greyscale picture where the lightness is transparency (white is totally transparent black is opaque)

1) Select your graphic.
2) Open the transparency pannel
3) Viiew options
4) from the pop-up choose make opacity mask (your image seems to disapear)
5) drawing in grey will reveal your image. (you can use blends, raster images, effects whatever)
http://www.layersmagazine.com/forum/attachment.php?attachmentid=703&stc=1&d=1207322333

to return to the drawing click on the right side in your transparency panel.
http://www.layersmagazine.com/forum/attachment.php?attachmentid=704&stc=1&d=1207322432

Now this will mean your resulting file is not a vector only file, so transparency flattening quality etc are important, but there is plenty in the online guide about that.

if you want to change anything in your mask select the object and click on the black and white picture on the right

So using a 20% transparent brush after making a white square in the background will be much like erasing from the picture, I use this especially with meshes, good way to tweak an erasing for the undecisive ;P