Photoshop Lasso Tool

Lasso tools (shortcut L) are similar to Marquee Tools, the difference is, lasso tools are manual. I'll explain the three lasso options avilable in Photoshop.

Lasso Tool

This is just like drawing a selection area in the image. The shape may be any as you're free to draw the selection line. See below for details (save the image and fire up photoshop)

Ok, I assume you've turned on Photoshop and opend the above pic (tip: you can just drag this pic from here to your photoshop window)

Let's throw some Lasso in the above pic. Select the Lasso tool . Feel free and draw a graph with this tool and realize that you're actually drawing a selection. When you close a loop in the end and release the Left Mouse button, you can see marching ants around your selection ie the area is selected.

In the above pic I've just started drawing the selection with Lasso Tool.

The ways of ending the selection are either you close the loop or release the left mouse button wherever you are. Compare the results yourself.

I guess you now know the difference between Marquee Tool and Lasso Tool. The lasso helps to make selection how we want it. There are two other lasso tools which are explained below.

Polygonal Lasso Tool

This is similar to lasso tool we observed above. The difference is it is used to draw perfect polygonal selection with the help of straight lines. Unlike lasso tool, this is started with left clicking on the starting point (don't drag). Then point to the next spot where you want to end the straight line. Select something like shown below:

Notice the Polygonal Lasso cursor has a small circle besides it when you're about to end the loop. Another way of ending the selection is double click wherever you've reached, a straight line will be drawn from this point to the starting point in this case. Note: if you need to get back to the previous state (ie if you plot a wrong point), just press Delete key. Try doing this.

Magnetic Lasso Tool

This one's an interesting tool. I'm sure you'll know yourself when you use this for the first time. It is used for the well defined edges in an image. An example is the image we're currently working. See the blue shape of the parachute. It's so well defined that we can use this automated Photoshop tool do our work. Our objective is to select the blue parachute only. Let's use the magnetic lasso tool then. Start off from a point on the edge of the blue thing.

After the initial point is clicked you don't need to click now, just move your mouse towards the right of the image. To be precise move the mouse along the edge of the parachute and move slowly, in this way the selection will be smooth.

(i don't know why the magnetic lasso cursor is not shown by print screen)

When you're moving the mouse, if the tool automatically doesn't select the points, just move your mouse a bit (up n down) on the edge till it does assign another point. Still if it doesn't left click to assign a point manually and move further. Manual clicking is required especially in corners where the tool needs to turn around, see below:

So you need to be slow and steady in corners when turning the direction. Go ahead and do your thing untill you get something like this:

If you plotted a wrong point or if the tool itself assigned the wrong point, step backwards by pressing Delete key. If you need to end the selection without completing the loop, double click wherever you are. Try the Magic Wand Tool, it's similar to Magnetic Lasso.

You might want to get around with Magnetic Lasso's Option pane. This can be useful

Width box indicates the number of pixels the magnetic lasso tool uses to find the edge. An increased value of Edge Contrast helps to select the edge more precisely, try giving 75% of it. Frequency is the number of points the tool assigns while moving the mouse. It ranges from 1 to 100. Try changing all the options avilable and compare the results.

A few things which i may have missed out:

• Lasso tool options are avilable similar to Marquee Options, see the options pane. You can also Feather the lasso selection.
• Holding shift key while drawing with polygonal lasso tool helps to draw perfect 45o lines which can be used to draw shapes like diamond, triangles etc.

So you've learned the three ways of manually selecting desired area in an image. There are a lot of use of all the three tools. Out of context, I'll tell you what you can do with the selection you just made with magnetic lasso tool. I assume you've made the selection like the one below:

Now press Ctrl + Shift + U to desaturate the selection. Desaturating means making the selection out of colours, in other words Black & White. If you can see the blue colour has gone, with the parachute area still selected go to Image >> Adjustments >> Color Balance (Ctrl + B). Make the following settings by either dragging the color bars or entering the numbers approximately same as these, you can try with your own colors. Make sure "Midtone" is selected in Tone balance section of the dialog box below

When you're done press Ok. The B/W (originaly blue) area has turned to Green. Press Ctrl+D. This removes the marching ants visible when the area is under selection. I hope you have the following result now.

This thing I just explained is not related to Lasso tool, I just did it for your refreshment. It is just an example out of many other things you can do after you make the required selection.