Rime-lapse

2008-12-09 21:49:34.000 – Ryan Knapp,  Staff Meteorologist

Rime time.

Over the last few months, I have been dabbling in time-lapse photography of subjects relating to the summit. As of yesterday, I had only been satisfied and posted one video and that was in our ObsCast a few weeks ago on the subject of our barograph (November 10, 2008). In that video I shot a picture every 10 minutes over 3 hours to show how the pressure trends on an instrument that barely moves. The resulting video only lasts a matter of seconds but shows movement that even I had never seen up here. So, then I wondered, what else I could shoot.

While reading in our forums, like I do every day, the subject of rime was brought up. The subject has crossed my mind but there are so many issues involved in shooting this video that I didn’t really know how to set forth on doing this. It is so difficult that a professional photographer tried it and failed. And it is not like he didn’t try. We fashioned up a heated box and put it some place fairly sheltered but the results were either failure due to rime still forming over the heated glass, the box tipping, or problems with the camera itself. So, if he had issues, where do I, an amateur stand a chance?

Setting forth, I did not want to try the heated box again. I did not want to leave one of our cameras or my camera out in the cold, riming conditions for any extended period of time. Even if I did have a camera that could withstand the conditions, getting the same exact position for every image is a lot harder to do in windy conditions than I had time for. Finding some place that got a lot of rime that wouldn’t get knocked off and would actually accumulate in a “short” amount of time is a problem because the best rime forms on places that get wind. The instruments were a definite no go since we clear them once or twice an hour. And other locations were also hard due to time and weather.

But all was not lost, as a volunteer stepped up to the plate with some ideas that got me aspired to start looking into doing it again. Our volunteer, Ed O’Malley, started writing in the forums that he had a small webcam that might be able to do the job and that he would bring it up here his next week of volunteering on the summit. Since Ed has been up here numerous times, he knew what kind of weather to expect and whether or not his camera could handle it.

So, when he arrived the week of November 19 to November 26, 2008, the project was a go. The camera that Ed brought up was a “micro video camera” which was an SUV Cam Pro by a company called Elmo. The camera was a “pen” type camera that measured 1/2 inch by 3 inches with a 10 foot camera that had to connect to a recorder that uses an SD card. This would be a limiting factor as the camera was waterproof but the recorder was not, so 10 feet would be our limit.

I looked around the summit for a good shooting location and found a pipe on the top of the parapet where our instruments are located. We do not deice this pipe and it was across from a protected opening that would allow the recorder to remain inside. Next up was setting up the recording speed and resolution. We settled on 3 fps (frames per second) to extend the recording time at a resolution of 704 by 480.

Eureka! We had a camera, we had an object to rime, we had a location to mount the camera and we had the recording time. All we needed was the weather. And here is where we hit a problem for most of the week. Most of the week was either clear, which has no rime, or very cold, which inhibits the amount of rime that forms. We have found that temperatures between 0 to 20 above are the best conditions for rime to form in fog. Our best day for temperatures like this would be Ed’s last full day up here, Tuesday, November 25, 2008.

The camera was set up and recording started from roughly sunup until sundown, about 8 hours and 15 minutes. Since I sleep during the day, it was all up to Ed to keep the lens clear. So, diligently, Ed went out every 15 minutes or less to deice removing his glove and holding his fingertip over the lens for a few seconds to thaw it out. The lens would stay thawed for a few frames then ice up again. By the end of the day, the camera was encased in ice with only the lens remaining relatively clear. And it was coated first in rime then glaze icing making it look like a jaw breaker of sorts with the different layers that formed.

We then downloaded the footage to edit in iMovie. This is where we hit a problem. The format that the video was shot in was a format that was not recognized by the version of iMovie that we use. So we set off to try and convert the video to a different format. Ed spent hours trying to find a format that worked but after hours of converting, we kept running into problems. Ed decided rather than waste more time here, he would take the video home; convert on a program he knew would work and send me the raw footage once converted for me to work on.

Flash forward to December 4, 2008 and that is where the project approached the finish line. The video was sent to me in seven-200mb segments that I had to download. This took some time to do. I then imported them into iMovie, which took more time to do. I finally got down to preliminary editing on the sixth. I went through the 8 hours and 13 minutes of footage and took out any footage that was either obscured by rime or by Ed’s thumb. This got the preliminary usable footage down to 1 hour 11 minutes. I then went back through and further cleared up the usable footage, editing out additional footage that was too fuzzy to see the rime or a little bit of obscuration that I missed the first time. This got the footage down to 37 minutes. I then exported this and re-imported it to speed up the footage as one clip. I sped it up once making the clip go from 37 minutes down to 7 minutes and 30 seconds. This was still a bit clunky, so I sped it up again compressing it down to 1 minute 30 seconds. This was close but still not quite fluid, so I nudged it up one more time to get the length down to 45 seconds.

I then exported this and re-imported it for post production and to do a secondary clip. The secondary clip was adjusted to try and make the raw footage a bit clearer by adjusting color and hues, brightness, contrast, sharpness, and depth. After we were satisfied, I put the two segments together, added titles, transitions, and music then uploaded it to our Youtube account. The end results can be seen below (or go to our youtube site to see it in a larger format):

So this was our first attempt at rime time-lapse or “rime-lapse” for short. It’s rough but you get the general picture. We would like to try this again in the future but change a few things. First, work on a method to possibly keep the camera ice free on its own. Second, if not heated, de-ice it with a finger more often. Third, record in a format iMovie recognizes. And last, get weather conditions that are more ideal for rime ice formation. But overall, for a first attempt, I think the footage came out good enough and is pretty cool. I hope you agree.

 

Ryan Knapp,  Staff Meteorologist

Overview of Lapse Rate Research

May 20th, 2024|0 Comments

Overview of Lapse Rate Research By Karl Philippoff As a weather observer and research specialist on top of Mount Washington, in addition to my usual observer duties such as taking hourly observations, releasing forecasts,

Deadline Driven: The 12-Hour Shifts that Power Weather Forecasting from the Northeast’s Highest Peak

May 9th, 2024|Comments Off on Deadline Driven: The 12-Hour Shifts that Power Weather Forecasting from the Northeast’s Highest Peak

Deadline Driven: The 12-Hour Shifts that Power Weather Forecasting from the Northeast's Highest Peak By Wendy Almeida  As a new member of the Mount Washington Observatory team, I wanted to gain a deeper understanding

Find Older Posts