Mac Hot Tips #2

Transparencify Backgrounds

Preview is the stock Mac application that opens PDFs and graphic images. One of its hidden gems is the ability to remove backgrounds and make them transparent.

To do so, open an image, show the Markup toolbar, and select the Instant Alpha tool  (the magic wand, second from the left). Then, click and drag over part of the image background.

As you drag, Preview will select that area, including similarly colored adjacent pixels, highlighting it in pink. As you drag further from your starting point, the app will select a greater range of nearby colors on the spectrum.

When you’re satisfied with your selection, let go and press Delete. The selected portions of the image will disappear, leaving nothingness. Or, to keep just the background, you can invert the selection using this Edit menu command and then delete. You can save the resulting image as a PNG to retain the transparent background.

It’s the Printer’s (de)Fault

Are you unsatisfied with the default settings when you print? Do you find you consistently have to change one or more of them?

Behind that print dialog is the Common UNIX Printing System (CUPS), which manages all printers and printing operations on your Mac.

You can enter the CUPS interface in a web browser by visiting http://localhost:631/printers. You might find that the interface is disabled, in which case you can open Terminal and run this command:

cupsctl WebInterface=yes

Then, you can explore all of the settings available for each of your printers and specify the ones that applications should offer initially when you issue the Print command. Learn more in this MIT Knowledge Base article.

Alternatively, some printers have their own web interface that you can visit using a toolbar button in the print queue, which you can open from the Printers & Scanners pane of System Preferences. You may find similar options there for setting printing defaults.

Mail Rules!

If you’ve worked with me, you probably know I’m a big fan of Mail, Apple’s stock email client on the Mac. I love how flexible it is in helping me manage my email.

You’ve probably also heard me complain about Gmail and all its idiosyncrasies. The only feature of Gmail I truly appreciate is its adoption of a unified inbox that includes sent messages.

As I mentioned in Big Sur Gripes & Greats, I created a Conversations smart mailbox that aggregates all messages in the Inbox and Sent mailboxes of all five of my email accounts.

For me, a large part of Mail’s underlying power is Rules: the ability to use criteria to act on incoming messages. You can find Rules in Mail Preferences.

For many years, I’ve used rules in Mail to help me distinguish among messages I receive in each of my accounts. Among other actions, Mail supports changing the background color of listed messages.

So, I have five rules, each looking for messages associated with one of the accounts and setting the background color to my specification. This results in a colorful Conversations mailbox where I efficiently decide which messages to view without having to switch to each specific inbox.

You’ll notice in the screenshot above that there are also options for Outbox Rules and Act-On Rules. These special features are thanks to MailSuite, a collection of tools that extend Mail’s functionality.