How does Gotham City summon Batman on a cloudless night?

Given that the Bat Signal relies on reflection from cloud cover?

Well they could just use the red Bat-phone. I always felt like the bat signal was a terrible misuse of public funds when you have a direct telephone line.

Did Batman have someone on the payroll watching for the bat signal? How was that supposed to work exactly?

Wikipedia, (Bat-Signal - Wikipedia), says that the signal has been used on buildings in Gotham as well as the sky - that would make sense when the sky is cloudless and not reflective enough.

It also points out that the Bat-signal is a psychological weapon to intimidate the criminal element, as well as just a way to summon Batman.

Don’t be ridiculous. It’s never a clear and cloudless night when Batman is needed! Gotham City is dark and moody by design.
Miller’s The Dark Knight Returns has the Bat-Signal projected on the side of a building, I suspect because he thought the Bat-Signal on the clouds was dumb and unworkable.

In fact, if you just put a relatively small bat outline on a spotlight I seriously doubt if you’d get a crisp, easily visible bat sign the way it shows up in the movies and the comics, but I’ve never tried it or seen it done.

By the way, I don’t recall a “red Bat Phone” showing up before the 1960s TV series. After that came out they introduced it into the comics as well, but I honestly don’t remember seeing a red phone in any 1950s or early 1960s Batman comic.

There was no phone, since it would be a simple matter to find out who was at the other end. The Batsignal was used primarily because no one could trace it back to the Batcave. Also, in the days before cell phones, it let you contact Batman if he was out on patrol.

I seem to recall Batman has something set up that would notify him if the Batsignal was turned on.

The way the bat signal was drawn in the early days of the comic didn’t seem to indicate that the bat image was projected on clouds but was projected onto the sky. And as a kid, it never occurred to me that there was anything wrong with that notion.

Someone needs to ask Mythbusters to have a go at this.

What about during the day, when the sun was shining?

They could get around this whole problem by upgrading to some sort of hologram projector. Or Bats could just donate it himself to the police department, he probably already has one at his cave ready to haul out and install on the police department roof; just waiting for some villain to try a plot that relies on the weaknesses of the standard Batsignal. Fortunately, he was prepared.

Robin: Aren’t we going to close up the BatCave?
Batman: Why bother? If the Commissioner really wanted to find the BatCave all they’d do is trace the wire. TV writers have no sense of logic!
–“Batsman” , the MAD magazine parody of the TV show.

The bit David Letterman did about the ending of the first Tim Burton Batman film was a laugh riot, but I guess they told Batman about it in advance.

The signal in the newer movies isn’t a crisp, clear image like in the comics or some of the movies. It looks like a spotlight on clouds. Also, just the beam from the spotlight would be very noticeable, even without clouds.

One episode from the original Super Friends TV series (“Gulliver’s Gigantic Goof”) featured the daytime Batsignal. Instead of being used to summon the Dynamic Duo though, it was used to alert Superman that the Caped Crusaders were in trouble (or more accurately, it was used by the villainous Dr. Gulliver to lure Superman into a trap).

Superman gave Jimmy Olsen a watch with an ultrasonic signal. Dick Tracy had a two-way wrist radio. You’d think with all his wealth and scientific genius, Batman could have come up with a pager.

Or nowadays: “b-joker n town need help kthx bye! Gordy”. No muss, no fuss, and Bruce Wayne can check his texts under the table while in a meeting.

It seems to me you might be able to do it with a long barrel with a pointlike light source at one end and the shadow mask at the other. Or possibly a pinhole camera-type setup, but that’d be horribly inefficient.

They release the BatCloud.

Keep in mind that for some of us, the red Bat-Phone is canon.

Which trumps all other efforts to relate stories of the Dynamic Duo.*

*also canon, ftr.

I was working at a small amusement park when the first Tim Burton movie came out. The park had one of those spot lights that rotated into the sky to advertise “Come over here, something cool is happening!”

We tried to make a bat signal out of it, it never worked. We tried a single mask, a tube shaped mask, everything we could think of, nothing worked. The one that worked best was an inverted tube mask, the reverse of what is here.

We needed something closer to a theatrical light with a gobo. Flood lights don’t have cohesive enough light for that application.