Magic Wand Tolerance Problem

T
Posted By
tmalcom
Nov 10, 2003
Views
1738
Replies
8
Status
Closed
After upgrading to CS, I’m having a problem with the magic wand when I use it in a layer. It seems to be ignoring the tolerance setting altogether. Here’s how I reproduce the problem:

Make a new file with a pure white background
Make a new layer (Normal blending, 100% opacity, 100% fill) Make a small square selection
Feather it by 1 pixel
Fill with black
Set the Magic Wand Tolerance to 1, anti-aliased to off, contiguous to on, and use all layers to off Click the Magic Wand in the solid black

The result is that it selects the entire black square along with the feathered edges, not just the pure black. Setting the tolerance to any number results in exactly the same selection. Selecting the transparent area of the layer also makes the same selection (inverted, of course). However, if I flatten the image, the tolerance works perfectly.

Additionally, if I select the entire layer contents by Ctrl-clicking the layer, the selection marquee is in a different place.

I’m mystified. Anyone know why the tolerance setting is being ignored? I’ve trashed preferences, rebooted, and it didn’t help.

Tom Malcom
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P
Phosphor
Nov 10, 2003
Tom…

Please carefully read Ho’s first post in this thread <http://www.adobeforums.com/cgi-bin/webx?128@@.2cce49e6>, read the whole thread and repost your problem there.

Just in the interest of trying to gather all problems discovered with Photoshop 8 in one place so the engineers—who ARE definitely paying attention— don’t have to jump all over the place.

Thanks.
PC
Pierre_Courtejoie
Nov 10, 2003
Tom, did you set the Eyedropper tool’s Sample Size to Point Sample ? If you set it to 3×3 or 5×5, the Magic Wand will give you results that you don’t expect, if you don’t know this…see this thread: < http://www.photoshoptechniques.com/forum/showthread.php?s=&a mp;threadid=157> (you might need free registration; there is no spam, nor ads…) it highlights the relationship between those two tools…
KA
Ken_aka_photon
Nov 10, 2003
Pierre,

Thanks for the link.

Ken Storch
PC
Pierre_Courtejoie
Nov 10, 2003
You are welcome, Ken! You are very welcome to share your knowledge over there too!

BTW, I took the liberty to link to your pdf in PST.
T
tmalcom
Nov 10, 2003
Pierre,

The eyedropper setting was one of the first things I checked and it is set to Point Sample. Unless there’s some other setting that I don’t know about, it appears to be a bug.
KA
Ken_aka_photon
Nov 10, 2003
Tom,
I’m seeing the same results, and I’m not sure why only the flat version works as expected.

Pierre,

Thanks, I take it as a compliment that you posted the article link. When I have time, I’ll poke around PST furhter (I haven’t for a while). Right now I’m working on several more articles in addition to my teaching, and I’m stretched a bit thin.

Ken Storch
SB
Scott_Byer
Nov 11, 2003
Note that this is not a change from Photoshop 7. For this particular case, checking Use All Layers is appropriate. Having it unchecked seems to imply that the transparency for the layer isn’t being used. I’ll have to dig through some history to figure out why this was done this way (it’s deliberate).

Note that the Magic Wand produces a hard-edged selection, whereas control-click in the layers palette just lifts the transparency and the outline will be at the 50% level. Thus, I expect the selection outline to be different between the two.

-Scott
T
tmalcom
Nov 11, 2003
This seems totally counter-intuitive to me. Yes, Use All Layers solves one problem, but creates many more. Let’s say you have two (or more) layers with the same color range you want to select. By turning on Use All Layers, you then have a selection that includes the color range in the other layers. Thus, you have to deselect those areas you don’t want. Turning on Contiguous is only helpful if the color ranges in the two layers don’t overlap at any point.

What this means in practical terms is that I have to turn layers on or off if I want to make a Magic Wand selection, which is not always possible. Or it means that I have to copy the layer I want to another file, flatten it, and then make my selection. All this adds an inordinate amount of labor to my workflow. This is insanity!

The Magic Wand on a layer should work exactly the same way it does on a flattened image. It should select only the colors within the specified tolerance and no more.

Tom Malcom

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