I have been doing some research into the use of the pen tool and clipping paths. But alas I don't understand.

My questions are related to selecting and removing backgrounds / extracting a subject, not text or graphics.

The tool while precise is fairly complex to use, I seem to be able to get similar results faster using other selections tools and refine edge. Yet I continue to read about creating clipping paths (points) and including this information in the image file. I don't believe this can be done with a jpg, and on top of that of what use would this be for the end user?

I see this for adds requesting product photography.

I am trying to determine the benefit of learning to use this tool.

Sam

Clipping paths are often used to remove the background or to separate the subject from the background, so that each can be processed differently.

This hinge image was clipped from the background, a drop shadow inserted, and then a new white background added.



This screen door latch was photographed on a plexiglass "rig" as an assemply, and then "clipped" from the background to give the illusion of the product suspended in air:



This spider was photographed in a glass jar, and the spider and the glass components needed different processing treatments to achieve the effect:



---------

Sometimes images are stacked in post, to indicate a series or collection. Photographing the items individually, stripping them from their background and arranging them in post is often the only practical method.

+ that paths, being vector based, are resolution independant.
Also very useful for actually 'drawing' stuff -
A tool that's well worth becoming familar with ... imo.

'Going the other way' ... ie making a selection, then using paths (Make work path) to create a vector based version of said selection can also be useful / interesting for some stuff.

pp

Back in the "old days", one only had the option of using a clipping path with layout apps such as QuarkXpress (only precise/hard edges).

Now, one can use alpha channels for pixel based transparency in print layouts such as InDesign, which can have soft pixel based edges.

Sometimes, a pen path is quicker and easier as pixel based methods may leave poor edges that need lots of fine tuning.

The pen tool can be used to make an alpha channel, it does not have to be used for a clipping path. This allows one to cut-out elements with a combination of precise/smooth curves and complex pixel based elements - all in one mask. For example a portrait shot, one may wish to have precise/smooth pen paths to isolate the shoulders and body - while pixel based masks can be used for fine hair. One combines both into a single alpha channel mask for the best of both methods.


Stephen Marsh

Originally Posted by Sam The tool while precise is fairly complex to use, I seem to be able to get similar results faster using other selections tools and refine edge.

It really depends on the image and on the results you need. When you're dealing with clean, sharp edges and need precision, the pen tool will usually give the best result. But you're right: It's a tricky tool to learn. There are lots of video tutorials, most of them mediocre. You have do some searching to find one that's helpful.

Bert Monroy is a master at it:
http://revision3.com/pixelperfect/pentool

Yet I continue to read about creating clipping paths (points) and including this information in the image file. I don't believe this can be done with a jpg, and on top of that of what use would this be for the end user?

Vector paths are stored in the jpeg. That's useful if you open the jpeg in Photoshop and want to use the path again.

Thanks everyone. Your right paeno all the tutorials I have seen are mediocre at best. I will try the one you linked to.

Ziggy, If I tried to extract that spider with a pen tool the Mayan calendar would end before I got two legs done!

I will take a few more stabs at this.

Sam

Peano:

Do you recall a video done by Eddie Tapp covering the use of the pen tool? It was about 10-15 minutes long and Eddie selected an old camera and flash unit. It was about the best I have seen on the subject but although I thought I had a copy I cannot find it. I am sure if people saw this video, they would completely get the tool and it's use straight away.

Anthony.

As you were..! Found a copy and uploaded to my webpage here...

http://www.anthony.ralph.clara.co.uk/pt4_pen_tool.mov

Well worth watching in my opinion. A.

Originally Posted by Sam Peano: Do you recall a video done by Eddie Tapp covering the use of the pen tool? It was about 10-15 minutes long and Eddie selected an old camera and flash unit. It was about the best I have seen on the subject but although I thought I had a copy I cannot find it. I am sure if people saw this video, they would completely get the tool and it's use straight away.

I recall watching that one several years ago. It doesn't seem to be available any longer.

Originally Posted by Peano I recall watching that one several years ago. It doesn't seem to be available any longer.

I found a copy in my archives; put it up on a web page for a few days so anyone who wants to can view it.

http://www.anthony.ralph.clara.co.uk/pt4_pen_tool.mov

Anthony.

Anthony,

Thanks for the link. This was a good explanation. I will need to dedicate some time to learning this tool.

Sam

Originally Posted by Anthony I found a copy in my archives; put it up on a web page for a few days so anyone who wants to can view it. http://www.anthony.ralph.clara.co.uk/pt4_pen_tool.mov Anthony.

I was referring to the one you described as having a camera in it. I haven't been able to find that one again.

Originally Posted by Sam Anthony, Thanks for the link. This was a good explanation. I will need to dedicate some time to learning this tool. Sam

It takes practice before it will save you time. One tip: learn how to use the Direct Selection Tool to add anchor points and modify segments of the path. It will save you lots of aggravation.

I found this to be a pretty nice video tutorial:
http://www.youtube.com/watch?v=IDrtyNmp3A4

Originally Posted by arodney I found this to be a pretty nice video tutorial: http://www.youtube.com/watch?v=IDrtyNmp3A4

Good tutorial Andrew...

Anthony

Originally Posted by arodney I found this to be a pretty nice video tutorial: http://www.youtube.com/watch?v=IDrtyNmp3A4

His very first "lesson" is wrong: He says the pen tool can't cover more than 90 degrees of a circle. In fact it will cover 180 degrees between two control points.

I think I read it in some old Kelby's book: mastering the Pen tool is as easy as ABC.

Essentially, you create a new document ~ 900x600 (or whatever), select serif-less font (if you want easy) or Times New Roman (if you want some challenge), type


ABC


in some huge size (to cover the most of the document) and start using Pen tool, trying to match the exact borders of the letters.
"A" starts you with the most simple path (all strait lines),
"B" adds a bit of curves (in math they are called splines),
and "C" takes your splines to a next level.
After you do it at least once you'll get enough experience to use it on more complicated targets.
HTH

Originally Posted by Peano His very first "lesson" is wrong: He says the pen tool can't cover more than 90 degrees of a circle. In fact it will cover 180 degrees between two control points.

Yes and no. No in one move (yes if you take the extra step of making a convert point on that first click as you apparently did). Make one click with the pen tool and drag, can you cover more than 90 degrees?

Originally Posted by arodney Yes and no. No in one move (yes if you take the extra step of making a convert point on that first click as you apparently did). Make one click with the pen tool and drag, can you cover more than 90 degrees?

I didn't make a "convert point" (whatever that might be). I used two ordinary control points.

Listen again to that tutorial. I quote:

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“How far can we make an arc with the tool?”

“I’m going to click here, and I’m going to click here, and I’m going to stretch the handles.” [note the plural ‘handles’]

“You can do 90 degrees with the tool. You can do less than 90 degrees as well, but you can’t do more.”

The person doing that tutorial doesn't understand the tool. It's as simple as that.

EDIT: If you make just one click and drag, as you suggest, you get a control point, not a path. The person in the tutorial clicks twice, making two control points. He evidently doesn't understand that he could click and drag both control points. He only drags the second.

It's not a major felony. It just illustrates my earlier caveat that a lot of people record tutorials to teach others something before they've learned it themselves.

If you don’t know what a Convert Point is, you should check out the functionality (and understand the term).

You made two ‘ordinary’ control points. Yes. You (I) can’t make more than 90 degrees WITH the 2nd click and drag. That is, click once at the top of the circle (12 oclock). Click again at the bottom (6 oclock) and drag. Not possible to drag and make the full 180 degree part of the path. Now click once at 12 oclock. Drag to 3 oclick and drag. You CAN with jus this move, get 90 degrees. That is his point although as you point out, he could have also illustrated how to get 180 degrees with additional moves.

You can go into semantics about the tutorial and yes, I agree with you in that respect although what was illustrated visually is quite clear. It is a very short and useful tutorial for beginners, the main takeaway is the use of the Convert Point (Alt/Option) usage.

The other tutorial is also decent but really long, somewhat confusing and we could also nitpick about some of the points made. For a beginner, I think the shorter tutorial is a useful start.

It isn't just semantics. When your aim is to teach beginners, you don't help them if you tell them the pen tool can't do something that it can do. That's just something they'll have to unlearn later.

The instructor used only one control point because he didn't know better. Don't make excuses for poor teaching. Note the error and move on.