You've really got two questions there: how long should intervals be, and how long should blackouts be?

My rule of thumb for blackouts is about 10 seconds. Audiences get fidgety in blackouts and long ones tend to ruin pace (unless it's pacing done on purpose, which is more about playwrights'/directors intentions than about anything else), as well as confusing an audience to when the show has finished. Long blackouts also have the added effect of making the show seem drawn out and boring to the audience. I know from a technical point of view, if the actors are taking longer than 10 seconds I get antsy (as SM) and can often throw other timings off like lighting cues. If there are genuine issues with costume/set changes, then perhaps a rethink of who does what when is in order, along with a rethink of whether those costume/set changes are necessary. (This is especially true of touring shows)

As for intervals, that's hard to judge. Recently at Ronnie Burkett's show, I was stunned to find out that he had no interval. His shows usually run for a good 2.5 hours or so, and usually have intervals - 15/20 minutes in the middle. The pace was good enough for the show that I'm not sure it mattered, but I do know that sitting still for so long tends to make your legs go a little numb. Normally I find his pacing so fast, you need a decent break in the middle just to catch up with it all. On the other hand, I've seen shows where we've come back from an interval only to be bored to death for three hours, and others where an interval ruined the pacing of a fairly short show. Obviously it depends on the length of the show, but let's go with an average of a couple of hours. A good 15-20 minute interval in the middle is fine. I think the old custom of having intervals between first and second, then second and third act, can also be disruptive to audiences these days - who have less fortitude and willingness to watch a show for so long through a whole evening.

Mostly, intervals seem to be about going to the bathroom, getting a drink, stretching your legs, and buying merchandise. Ten minutes is too short, 30 minutes too long.

Raising the lights should be left only to pre and post show cues I think, and unless they involve audience participation or actors in the audience seating, usually signal to the audience that it's time to leave.

Music during blackouts is fine, but again, if you're needing to have blackouts for so long, then perhaps you need to rethink what you're doing. Of course, there's nothing wrong with turning the scene changes/long intervals into a part of the show itself - I've seen this done well using circus clowns (funnily enough, both human and marionette, but in different shows) and other 'extras'.

Puppets and patterns at
Puppets in Melbourne

Interval in my opinion should be 20 minutes at the most.

With regards to blackouts, they are my pet hate particularly in Perth Community Theatre.

If you have blackouts lasting longer than ten seconds, it shows that the director has not done their homework with the logistics of the script being presented in terms of setting and costume.

It is also an insult to your actors hard work in performance, once your audience's attenion has dropped, they have to work so much harder to win them back again...the more long blackouts the more this occurs and can turn a great production into a very sad train wreck.

If the problem is your venue...then youve chosen the wrong
play for the venue...more fool you.

The director, sm and technical crew should be working as a team to make the transition between scenes as seamless as possible, by coming up with solutions to the problems presented by the script.

A few tricks are;

1)Streamlining props - if it isnt going to be used as part of the action - don't include it!

I saw a production where a fully prepared dinner and wine were on the table and barely touched by the cast and totally irrelevant to the production as a whole...it could have been omitted....the scene was short and the scene change was long...not good.

2)Actors can move small props when they end their scene.

A production had a gentleman in the middle of the set going through old LP's (the old fashioned vinyl records from the pre CD/Ipod era for the younger set that dont remember) another person was reading a newspaper and drinking a glass of wine.

At the end of the scene when they walked off the stage the props were left behind when they could easily been taken off by the actors, the lp guy could have scooped the LP's up and he newspaper and drink could have been taken off by the actors..instead of having to be cleaned up by the stage crew...a very simple technique which would have shortened the scene change from 2 minutes (as it ended up being) to ten second

I went to see a production of a movie adapted for the stage, and it showed that it was originally a movie, their were at times 5 minute scene changes for a 2 minute scene, and the production suffered badly as a result, in all honesty it was torture to watch it, and the long blackouts made me totally lose track with the story.

3) Dress your set for minimal alteration during the course of the play, or if you can't build clever sets that can have bits pulled out or covered up quickly.

I'm prepared to put my money where my mouth is on this and run a workshop of how to overcome theses difficulties in staging...because its an area that isnt being tackled well in Perth.

Just a few thoughts, in short, its a case of the 6 "P's".

Prior Planning Prevents Piss Poor Performance.

That is the key to overcoming the dreaded blackout trap.

Cheers

Robert.

I consider 20 minutes to be the perfect interval. Smokers need the opportunity to get outside, either before or after obtaining liquid refreshment, then there's the queue for the Ladies....always longer than for the Gents. (insert humble plea to new venues and/or architects who might, by magic, read this to seriously install double the usual ladies' cubicles).
On the subject of blackouts I tend to fall in with Na, ten seconds is really about it. However, there are exceptions. If a BO is likely to go beyond 10 seconds due to a tricky change of some kind please bring in some relevant music or sound scape. It helps the audience to know that what they're experiencing is just a bridge to the next scene (it also covers the cough they have been holding in, the shoe shuffles as people shift in their seats, etc.)
One of my favourite memories is of a production of "Same Time, Next Year". We did the changes in full light, props and crew were dressed as hotel staff, a song that was relevant to the year the play had reached was played. It all worked and gave time for the two actors to do full changes including wigs. On a similar vein I recently saw a production of "Dangerous Liasions" where the crew were dressed in period and moved the furniture on the unit set to establish that we were now in a different scene. There were a couple of brief blackouts, mostly to permit actors to be revealed in position, and the whole thing flowed. It's not always appropriate to do this sort of thing but it's worth remembering.

PS: Na, I dislike being asked to leave, but that's mostly because I'm nosy and want to see what they're doing.

"Life is too short to stuff a mushroom"

I saw a show the other night, the length of which was increased by a full ten minutes, due to the three scene changes, each of which went for the entire length of a song. OK, there were costume changes happening as well, but precious little changed on the set.

www.meltheco.org.au

Yes Jeff I was there too.

I couldn't believe that the music wasn't faded out after the scene changes were finished.

Even on costume changes, clever planning can help. In 'Menopause the Musical' all of the actors had a total costume change whilst performing one number, and the audience didn't even know until the song was finished.

That sucks...you were left sitting just listening, and for little reason....that's just not right.

"Life is too short to stuff a mushroom"

Good topic, Gordon.

Intervals are good. A lot of people go to the theatre as a social event, which should be encouraged, and an interval allows them to socialise while getting their drinks, etc. Also there are probably a lot of second acts which benefit from having a more relaxed audience after having stretched their legs, had a drink, had a chat, gone to the loo, etc. (And a lesser desired but also important factor is the opportunity to leave at interval without disrupting the performance! If your show is really not appealing to someone, better to let them sneak out at an interval than to force them to stay against their own judgement and have them end up totally resenting you!)

The last professional show I went to (Deckchair Theatre) the audience was asked to remove to the foyer so the set could be changed. Happens fairly regularly in my experience, usually when the theatre has no other form of curtaining and they desire to set up something for dramatic reveal, and don't want to spoil the surprise. I personally prefer letting anybody who wishes to remain watch what goes on, but it's a matter of presentation. If you DO carry out set changes during an interval in view of an audience, then they ought to be presented like a performance...perhaps not to go so far as being choreographed (although it could be), but to display an atmosphere of precision and efficiency, with no actions that should NOT be seen.
The only time I remember it being a safety thing to clear the audience was when an object needed to be reset to swing out on a line above the auditorium, hence needing ladder access between the seats. Every other time I'm pretty sure it was aesthetic (ie hiding an actor/object prior to the audience seeing it)

The correct length for an interval is: long enough that people still feel entertained. Too short and they will feel rushed and not welcome. Too long and they will feel bored and not welcome. Obviously there may be a certain amount of set changing which will take some time...figure out how to make it more efficient; get extra hands if necessary, so that it takes no more than the good length of time for the audience.
No point in stipulating a fixed number of minutes. A night with two short plays may have a 20 min interval and feel too long. At a night of Shakespeare in Kings Park where the toilets are a 400m walk away up a hill, with long queues, 20 min will feel too short. It will depend on the subject, style and pace of the play to determine whether the audience is raring to go or needs longer, or whether they are looking at their watches wishing it would start again so it will end sooner..!
Often the actors themselves will need a break between acts, not just to change costume but to sustain the energy to continue at full pace. Too short and they may not have the stamina for act two, too long and voices & bodies cool down and lose their edge. Again, it's dependent on the type of show, and is a pacing element that ought to be worked out in rehearsal.

Music is an extremely useful way to smooth over scene transitions. Nowadays you have no excuse not to be able to tailor-make a short piece of music to fit your transition...the tools for sound editing are readily available on any computer. (though I used to do it easily enough in the old days of cassettes, you don't need technical wizardry). A ten second gap can usually be improved with ten seconds of correctly chosen music. Music can lead out of one mood and into another, and can sustain the energy over any forced break in the action. It can comment upon the scene and add context and subtext. The idea of 'choreographing' a scene change can also be assisted by music, presenting a show of slick timing and efficiency.

I TOTALLY AGREE with Robert J's first post about blackouts. HIs post was to the point and offered constructive suggestions. That someone got offended possibly reflects the dire need for his suggestions to be taken seriously!

Every play/set/scene change is going to come with its own unique problems to solve, so it will be difficult to simply teach solutions in a workshop. But it's definitely an area where skills can be explored and an improved way of thinking can perhaps be learned.

Scene transitions are a collaboration between the set designer and the director. It's the designer's job to create a set that achieves the aim of the play, including getting from scene to scene; and the director's job to implement the changes using cast and crew so it also serves the aim of the play.
Blackouts are an archaic and boring way of achieving scene changes. I dislike blackouts in general, and they are my pet hate too if they become a production number in themselves, because usually I can see for myself that they are unnecessary if someone had only thought it through.

Scene transitions are part of the play. They can be made into a feature (actors or techs in costume going about some business that suits the show and which happens to change the set moving us from one location to another) or, even better, incorporated into existing scenes. For instance, while an actor is finishing one speech, he has collected all the items that need to be removed. The next actor brings on what they need and sets it up while speaking their lines. Or the scene change goes on behind them while they are pulling focus and advancing the story. Lighting is obviously a good way to direct focus.

Of course, many scene changes actually denote the passing of time, and there may be times when a blackout actually is the best way to convey this. But to my mind this is only effective in a filmic sense, when the scene fades to black and then fades straight back up again. Any time there is an elongated blackout I'm more inclined to think something has gone wrong. Snap blackouts, or clever use of lighting to hide and reveal elements of the set and play, are a valuable tool and not what I'm complaining about here...it's the tedious practice of finishing a scene, going to black or dim while a ninja-like band of mechs rearrange the props, letting the audience fidget for 30 seconds or more, then bringing the lights back up. It halts the action and draws attention to design inadequacies. I see far too many examples of this done poorly, and where I get annoyed because it seems obvious to me how it could have been done better if only someone had thought about it.

Occasionally, a scene change is impressive by itself, in which case we want to draw the audience's focus to it and allow them to enjoy the transition. Other times they will enjoy it more if it has happened before they even realise it, right under their very noses. Or if a lot is seemingly accomplished, like magic, in the blink of an eye. This is an impressive blackout. Sometimes a good tension can be created by making some changes which keep the audience guessing until the final flourish when we suddenly realise what the stage has now become.

But you should also consider whether the scene change even needs to occur in the first place! Nothing worse than taking 30 seconds to bring on a table, for instance, and another 30 to take it off, when I can imagine the scene working perfectly well either without it or if it had remained there the entire time! Or if a lot of effort goes into making changes that hardly seem worth it.

I think too many directors think a SCENE change should not be SEEN, hence trying to black it out. Incorporated with thought and skill, scene changes can and should be an interesting and integral part of what makes a play entertaining to an audience.

Cheers,
Craig

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