How to Use the Mask & Instant Alpha Tools in iWork for Mac - Part 2

| How-To

In Part One of this two-parter, we explored the Mask Tool – one of several advanced features available in the iWork suite of applications. In this second part, we will examine the Instant Alpha Tool.

The toolbar icons for the Mask and Instant Alpha tools in the iWork apps.

These are the toolbar buttons for the Mask tool and the Instant Alpha tool.

Along with its sibling – the Mask Tool – the Instant Alpha Tool is available on all three iWork Mac apps: Pages, Keynote and Numbers. For the sake of simplicity, I illustrate by using Keynote. However, I underscore the fact that the specifics of these tools – and how to use them – are identical in all three apps.

As I mentioned in Part One, Keynote is a critical application in my stable of productivity apps for the Mac. There are so many features that make Keynote shine. Not a presentation goes by where I don't have people come up to me afterwards and say things like, "I didn't know that PowerPoint was so powerful!" or "That was an incredible PowerPoint!" All to which, of course, I respond, "PowerPoint? What's PowerPoint? This is Keynote on my Mac, you nimrod. Would you like to know more?"

Unquestionably, I receive this adulation on account of my magnetic personality, good looks, and self-effacing humor. In actual fact, it's a combination of effective presentation techniques and proper use of the capabilities and software tools present in Keynote – the Mask Tool and the Instant Alpha Tool being typical examples.

Let's dive into the Instant Alpha Tool.

So, why "Alpha," and does this mean there is an Omega Tool as well? Negatory on the Omega Tool. The name comes from "Alpha Channel" – a feature used extensively in high-end imaging and illustration applications. Think of the Instant Alpha Tool as one allowing you to hide unwanted areas of your image – portions of the image that are superfluous and distracting, like a background.  This is a process of combining an image with a background of any color to create the appearance of partial or full transparency.

A Keynote slide depicting an image without the Instant Alpha Tool applied.

The white background area of this "No Photography" image is distractingly gaudy.

Take a look at the illustration of the Keynote slide above. That white area just doesn't look professional. When I see this type of thing in other people's presentations, it makes me think that the author was lazy when preparing the images and graphics, or didn't know about the Instant Alpha Tool. Some of you may be thinking that this example slide looks just fine, but once you start working with the advanced tools available for you to tweak your images, you'll surely change your opinion. You really ought to shoot for producing nothing short than perfectly executed and rendered presentations.

Wouldn't the treatment shown just below be much more effective and exhibit significantly more professionalism?

An image with the Instant Alpha Tool successfully applied.

With the Instant Alpha Tool applied, all white areas in this image are rendered transparent.

Applying the Instant Alpha Tool to my image allowed me to prepare it just the way I wanted. As you will see, the finished product is far superior to the original version. The image is modified so that it blends in better with the message and the theme – or style – of the Keynote slide.

That white area was highly distracting and obtrusive. With the Instant Alpha Tool, the unwanted area of any color becomes transparent – think "hidden." I want to see just the parts of the image that are germane to the topic of the slide.

A Keynote slide depicting an image as the Instant Alpha Tool is being applied to it.

Applying the Instant Alpha Tool to an image is basically a three-step operation.

With very little practice it's simple to get the hang of using the Instant Alpha Tool. Referring to the illustration above, here are the steps I need to take in order to improve the image of the "No Photography" sign on this Keynote slide:

1. I select the image by clicking it first. This activates the Alpha button on Keynote's toolbar (as well as the Mask button, as it happens).

By the way, if you do not see the Alpha button in the toolbar, you can add it by going to View > Customize Toolbar. Then, from the Customize Toolbar panel, drag the Alpha button up and onto the toolbar, and position it anywhere you'd like.

2. With the image selected, I then click the Alpha button. You can also do this via Format > Instant Alpha. A little dialog box appears with simple instructions on how to proceed.

3. The cursor turns into a cross-hair. Since I want to delete (or make transparent) the white area surrounding the circle, I click anywhere in the white area. A blue or green "mask" appears on the unwanted area – that's a good thing.

4. I then drag slowly outward from the spot where I initially clicked. This increases the scope of the color selection – particularly important for areas where there are subtle color shifts or gradients. However, for solid colors, a single click will generally do the job. Note that if I continue to drag outward, eventually the symbol's red area will disappear as well, therefore the effect of dragging allows you to fine-tune the color range selected.

Once the Alpha Tool is activated, you can click as many times as needed in various areas of the image in order to build-up and get the effect just right. For more complex images, where areas needing to be transparent aren't clearly delineated or contiguous, this process becomes one of trial-and-error.

Focusing on the sign in question once again, notice that there are two white areas inside the circle. These were not affected by the click-and-dragging since the white pixels inside are completely isolated from the white pixels surrounding the circle. So, while still in Instant Alpha mode, I simply click-and-drag each of the two internal white areas until they, too, were masked out – eventually rendering them invisible.

Here's a power tip involving the magical Option key: By holding down the Option key while you drag, all instances of the color that you’re dragging over will be removed from the image. So, I could have just as easily removed all white areas at once using this Option key tip.

A Keynote slide depicting an image with the Instant Alpha Tool applied.

The Instant Alpha Tool's power is enhanced when using the Option key method for complex images.

The illustration above is a great example of the benefit of the Option key method. It's a fantastic time-saver when working with complex imagery with many – and possibly minuscule – areas of color you want to render transparent.

5. When satisfied with the application of the Instant Alpha Tool, I click outside the image to deselect it. I then proceed to do the Happy Dance – those unsightly white areas are now gone by virtue of being transparent. The No Photography sign seems to float over my slide.

A Keynote slide depicting an image with the Instant Alpha Tool applied.

Compare the before and after, and I'm certain you'll discover the power of the Instant Alpha Tool.

But, there's something not quite right yet because that little camera icon should not be above the red bar. The red bar should cover the camera to better convey the message that photography is prohibited, right?

The image I used actually consists of two superimposed images: the red circle-and-slash symbol, and the camera icon. The way the image was depicted initially, those white areas were totally opaque. I could have repositioned the image of the red circle-and-slash using the Arrange > Bring Forward command so that it was now on top of the camera icon. However, because of it's opaque nature, it would totally cover the camera icon from view. It would make no sense to do this.

Because the Instant Alpha Tool changed all the unwanted white pixels to transparent ones, I am now able to see the camera icon under the red circle-and-slash after re-arranging the two images.

The finished product, shown below, is very gratifying as it no longer distracts from the message being conveyed on the slide. The Happy Dancing is getting out-of-hand.

A Keynote slide depicting an image with the Instant Alpha Tool applied.

With the camera icon repositioned behind the symbol, it is no longer blocked thanks to the transparency applied by the Instant Alpha Tool.

Incidentally, you can restore the parts removed from the image at any time. To revert to the original image, select the image first, then choose Format > Remove Instant Alpha. To restore parts of the image removed using Instant Alpha, choose Edit > Undo Instant Alpha until the parts have been restored.

Why not give the Instant Alpha Tool and the Mask Tool a workout when preparing your next Keynote presentation?. Experience the adrenaline rush you get when people in your audience spread the word about what an awesome "PowerPoint" presenter you are.

Comments

Allister Jenks

Aha! Two images. I was wondering how on earth you preserved the shadow of the camera! I presume instant alpha isn’t that smart.

davidneale

Instant Alpha is also available in Preview and works in very much the same way, though the handy option-key function seems to be absent. And yes, because the scope of the selection is increased by dragging, Instant Alpha can leave the shadows visible.

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