I'm a big fan of star trail images... Shooting multiple 30 second exposures, and stacking them in Photoshop to create some truly amazing looking images. I've a few scattered throughout my photostream over on flickr, and a couple here in my galleries.
I'm by no means the first to be shooting star trails like this - there are hundreds of photographers out there who are shooting some absolutely amazing images, and have been for many, many years. One such photographer that came to my attention last year was a guy called Lincoln Harrison - a.k.a. Hakka, or Hakka69. Lincoln shoots some truly inspirational images in the wilds of Australia. Take a look at his amazing images over on 500px, or over on his Flickr photostream. One Word: "Wow!"
I'd been tinkering with different processing techniques for star trails at the end of last year - Initially, trying to boost the trail effect to give them more of a 'wow factor'. After many hours of photoshop adjustments, I found that changing the layer opacity on each individual stacked image, gave a faded effect across the duration of the trail length - it gave some great, different to the norm, results.
There was one small problem though - the task of stacking 200+ images in 'epic' trails, and manually adjusting the layer opacity on each and every one, was far too labour intensive. You could literally spend 4 or 5 hours on a single image. What I needed was a script, similar to my exisitng stacking action, but more versatile. I set about writing a Photshop action...
It soon became apparent that the need for input parameters, and the inability of a simple set of script steps to achieve a quick solution, was holding me back. Manual calculations of EV increments, counting files to be stacked... it was almost as difficult as doing it all manually. I needed a way to have a more user friendly way of achieving the same - something that would take my input EV's and as Nike would say "Just do it!". An so, a fledgling Photoshop script was born...
Midway through, I saw Lincoln post an image with a similar style to those that I'd been experimenting with - You can see that image here on his 500px stream. 225 x 30 Second exposures...
*** by Lincoln Harrison
I immediately dropped him a quick message, not expecting a reply - He has an affection rating of over 44,000 on 500px, and around 900 followers on flickr... I figured he must get a great deal of correspondance every day, and probably wouldn't have time to reply to every individual who randomly dropped him a message from the miriad of photography sites out there. To my surprise, and delight, a response came almost immediately - he discussed the technique he'd used on that image, and let me in on a few other secrets he used to achieve such stuning imagery. I'd not share that here - I'd leave that to Lincoln to explain, should he ever wish too... He employed pretty much the same technique as I had, with the exception of using an exposure adjustment to batches of images, rather than a layer opacity adjustment on individual images. I saw straight away the advantage of doing that - you could actually add some 'gain' to the stars too, and make the ends of trails brighter... Lincoln's reason for adjusting batches of images, was probably down to the time it takes to apply an EV change to each image... even when a custom action is recorded for each 'batch'.
So: What next? Well, I set about updating the script, with the help of a Russian programmer who knows PS inside out - Evgeny Trefilov - If you need any PS scripting or customisations, he's your man - truly outstanding work, in no time at all.
A few tweaks later, and I had a fully working script that takes a Start EV, an End EV, and processes all of the images in a chosen directory, stacking each one with the appropriate EV adjustment... The only pre-requisite being an open, blank document (black backgound...) with the same dimensions as the images you want to process. Click ok, and a lovely progress bar tells you how long it's going to take!
Here's a comparison of two simple stacked images, snipped from a longer duration shot I took back in 2009. This version contans 20 images of 30 seconds in duration (ISO:100, f5.6 18mm on the old Samsung GX-20!): On the left, you can see a traditional star trail - consistent across it's exposure... On the rightRe-edited with the Tapered trails script, with the 'comet like' effect...
Here's a crop from my recent post-wedding shoot up at Newby Bridge, Cumbria: One processed with a classic stacking script, the other, with my Tapered Trails script...
There's a Demonstration version available to download and give a try if you like the effect, and would like to try processing some of your own star trails to give them something a little different, and make them stand out from the crowd!
The demo version is limitted to stacking 10 images. If you like the results you see, you can download the full version, with unlimitted image stacking capability, from the link on that page.
Full instructions on how to install and run the script can be found there too.
Have fun! Let me know of any images you create, and I'll feature them in a follow up post here on my blog, along with links to your portfolio / website /
(Email me: email@example.com)