LAPSE-TIME PHOTOGRAPHY 39 



speed, or even at intervals of one hour. A four-week 

 run at two pictures an hour, giving 1,440 pictures 

 or sixty seconds' run, will, if done in natural color, 

 give a picture that will hold the interest for that 

 long, but it must be especially good to be worth even 

 thirty seconds' time on the screen, which would have 

 meant one hour intervals for a period of one month. 

 In California the average wild or cultivated flower 

 takes five days to make that would mean at ten 

 minute intervals, six pictures an hour, 720 in five 

 days and at twenty-four pictures a second, the stand- 

 ard projection time in the theaters, thirty seconds on 

 the screen. If the same rule were followed for 1 6 mm. 

 and the projection speed was on the old basis before 

 sound came it would mean forty-five seconds' projec- 

 tion time, rather too long or slow. So in making 

 lapse-time pictures you must figure what you are 

 making them for. Our present standard speed is 

 twenty-four a second, or as a home product is sixteen 

 a second each method has its uses. For lecture work 

 a series of lapse-time pictures at sixteen would drag. 

 If the same were shown at twenty-four some would 

 complain that they were too short, which is always 

 a good criticism. So in making your lapse-time pic- 

 tures you must know when the bud starts to open, 

 day or night; how long it takes before the petals fall; 

 how much of it is worth picturing as sometimes its 



