I'm confused about Anti-Aliasing

[Blac...@adobeforums.com]

I'm copying some vector art (monochromatic flats) from Illustrator and pasting into Photoshop as Smart Object. I am making selections from the flats to create individual paths to color however the edges aren't lining up. I end up with gaps between the edges and the lines are jagged.

Can someone please explain anti-aliasing? I am following a few video tutorials, one is saying turn it on and the other says to turn it off.

[Blac...@adobeforums.com]

Anyone?

[PeterK.@adobeforums.com]

Need more info. How are you making selections, and how are you creating "individual paths?" Do you mean paths as in with the pen tool? Which "lines" are jagged? Why are you doing this and what are you trying to accomplish?

Anti-aliasing means there are interpolated pixels between colour edges, smoothing their appearance. An aliased edge is where two colours butt against each other with no intermediate pixels transitioning between them.
(zoom in on this image to see it better)
<http://www.pixentral.com/show.php?picture=1iDwRFw14G4sV9edytZ2iEu1NWz8O0>

[Blac...@adobeforums.com]

Thanks Peter, right now I am trying speed up my process. I've tried to work solely in Photoshop and solely in Illustrator. I'm thinking it would be faster to start off in Illustrator and then mover to Photoshop (magic wand) and do all the coloring there. That's why I am trying to get a handle on anti-aliasing.

So are you saying that I need to turn on Anti-aliasing?

[J_Ma...@adobeforums.com]

I'm thinking it would be faster to start off in Illustrator and then mover
to Photoshop (magic wand) and do all the coloring there.

I wouldn't do that unless you absolutely need to. Illy has swatched-based coloring, which makes changing all red objects to pink a one-click procedure. Learn Illustrator. The time sepnt will be valuable, and helpful in your Photoshop endeavors as well.

[PeterK.@adobeforums.com]

I believe he's trying to do digital colouring/painting in photoshop of artwork. If that's the case, Photoshop is a good tool for that (unless you want to do flat colours and maybe simple shapes for shadows and hilights, then it may be better to try your hand at vector art).
For your starting flat colours (which you would use to make your wand selections) you want anti-aliasing OFF. When you're making wand selections, make sure anti-aliasing is off on your wand tool as well. In this way, your selections will always be based on the hard edges of your colour shapes and you will never have gaps in between the colour areas.
I'm still not sure what you meant when you mentioned paths, or why you're pasting smart objects. Note, if you rotate the smart object in photoshop, you have to make sure you have "nearest neighbour" set in your preferences for image interpolation to prevent anti-aliasing of the edges.

[Blac...@adobeforums.com]

Thanks Peter, I think I have a better understand of anti-aliasing now. Oh and I didn't know I could save my Illustrator projects as a .psd file, that's why I was pasting smart objects into Photoshop.

Done in Illustrator:
<http://img379.imageshack.us/my.php?image=gradient1eb3.jpg>
Done in Photoshop:
<http://img411.imageshack.us/my.php?image=tempzh7.gif>

[J_Ma...@adobeforums.com]

Nice, BF. Looks very good!

[Blac...@adobeforums.com]

Thanks, I still think I should do my flats in Illustrator because my adjoining lines in Photoshop aren’t exactly clean. Plus it should speedup my process up.

[Blac...@adobeforums.com]

Ok I'm home now and I still am not able to get two colours to butt against each other. What am I doing wrong?

<http://img185.imageshack.us/my.php?image=antioy0.gif>

[PeterK.@adobeforums.com]

If you want someone to tell you what you're doing wrong, it's customary to explain in detail what it is you are doing!

[Blac...@adobeforums.com]

I do all my line work and flat colors in Illustrator. For my line work I use the pen tool and for my flats I use Live Paint to color each section with a different base color. This will allow me to make selections in Photoshop to color each part selectively without touching the rest. I export as a .psd file and move over to Photoshop. In Photoshop I start making selections from my flats using the magic wand tool.

Instead of getting 2 colors butt up against each other I get this:

<http://img185.imageshack.us/my.php?image=antioy0.gif>

[John_R_...@adobeforums.com]

What's your Stroke color?

[Blac...@adobeforums.com]

I turn off the stroke once I lay my flats.

[PeterK.@adobeforums.com]

So are the gaps there when you first open the psd? When you export to psd from Illustrator, make sure that anti-alias is not checked. The psd you open in Photoshop should have all the colours butting against each other with hard edges. If the psd file is wrong then there's something wrong with the Illustrator file. Live paint may not be making the colours a perfect butt-fit.
Assuming the psd file looks good, then when you use magic wand, set a tolerance of 0, anti-alias is off, and one other little-known thing that affects the wand's range selection; the eye-dropper tool should be set to point sample, which samples only one pixel.

[Blac...@adobeforums.com]

No the gaps aren't there when I open the psd. I think I might have anti-alias on in Illustrator. I'll check it out later. Thanks guys.

[Blac...@adobeforums.com]

I know it's kind of late, but after I unchecked the anti-alias in illustrator that got rid of the gaps between colors. Thanks Peter.

[Don_Mc...@adobeforums.com]

If you ever get to the point where you want to commercially print work like this, be sure to read up on trapping. You will get a similar effect (a gap) unless trapping is done correctly, by you, or by the printer.

[Blac...@adobeforums.com]

Don, I have to admit, I never even heard about trapping. I did a search; you're talking about color trapping right? Looks like print shops tell you what the trapping value and they you enter that value in Photoshop. What’s not clear is how to tell whether or not you’ll have to do trapping, how would you know, do the print shops tell you?

[J_Ma...@adobeforums.com]

You can ask the print shop. They might be able to give you a useful answer. Trap all depends on the press being used. In CMYK mode, PS will trap your file for you (Image... trap), but you need the to know final output size to calculate the trap in pixels. Trap for small sheet-fed presses might range from 0.08 to 0.12 pts, which at 300 ppi would convert to 0.3 to 0.5 pixels. So a 1-pixel trap would be the best you could do.

[Blac...@adobeforums.com]

Ok, I follow you. Thanks J.