Video FX and editing. A How2 Do a photo-montage in Adobe After Effects video editing and FX software.
Fast, flashing images, subliminal effects and tachistocopic limits.
Since the advent of film, people have experimented with cutting together multiple successive images to create a stream of pictures a little faster than the human eye and brain can comfortably resolve. Sometimes called subliminal because there is evidence that even if the image is not consciously recognised it can affect the perception of the surrounding visual message.
As a result the fast stream of mages became a sign of brainwashing. Used in the conspiracy thriller, The Parallex View, to good effect and in the Michael Caine anti-Bond spy film, The Ipcress File.
In the days when film editing involved razor blades, tape and film cement, the image stream was constructed by cutting and joining a few frames of each image into a continuous strip. In these days of digital image editing the options are much more diverse. This post and associated video aims to examine those options and the different impact they give to the visual effect.
I should make clear I make no claim of expertise in this area, in fact I declare that I am a mere beginner having started using video editing and fx software only in the last 2 years. I have for many years used music recording and editing software, 3D modelling and animation programs and have been using Photoshop since version 3. But until a 2 years ago had merely dabbled in video. The improvement in machine capabilities to edit and manipulate video in the way that has been established in audio is relatively recent, at least at the non-professional price level. So my interest, the technology to pursue it and the opportunity and resources to do so have only recently coincided.
I do not provide this, or other planned tutorial and how-2 videos, in the belief they are the correct, best and professional way of doing something. The faults, a basic unfamiliarity with the software which leads to a lot of stumbling experimentation I hope to present as a feature. Professional experienced users will already know these methods, I freely admit that much of what I have learnt has been from AE tutorials posted by experts like EC Abrams Mikey etc.
I do not expect to be of much help to those professionals. But I hope that a description of how someone without that depth of knowledge discovered a method of doing a certain effect will be of some use to those who are at a similar naive level of experience with the software and its capabilities. While there is much satisfaction in getting a desired video effect to work right, sometimes there is just as much fun to be had exploring the software capabilities without a map and serendipitously discovering ways of doing something de novo. This is a short tutorial on a method of setting up still image sequences in AE that allows the order, transition effects and timing to be easily adjusted. I have seen tutorials about game montages, but nothing about tachoscopic, subliminal or ‘fast’ slideshow montages although it is a frequent trope in informational videos.
First, find your images. There are sufficient public domain images available on the search engine websites, unless you really need to confine them to a very specific subject. But lest assume you want a generic theme, like the history of transport.
You can carefully collect and size the images you want to use and store them in a dedicated folder.
Or you can open a search engine image page and just copy and paste image into Photoshop, until you have between 15 and 20 images. That will provide a second or two of a rapid image stream, more than that is probably undesirable. It is not an effect that is comfortable to watch for long if it is the dominant image on the screen.
Once you have a Photoshop image with all the pictures as separate layers, which you can name if you want, but the layer number is really all that’s needed, it should be saved out to a known location as a photoshop PSD file with a suitable name.
Then in a new project in After effects make a new composition at the size and frame rate you want about twice as long as the you think the clip needs to last.
Import the photoshop picture as editable layers and drop it into the composition so that the separate layers in the photoshop file create separate layers in the compositions.
Select all the layers and then decide how long each image should persist. It is possible to trim all the layers to a single frame, go to the start, move one frame forward by single press of the page down key and then Alt-] to trim all the layers to a single frame. Then go to -/- key frame assistant. Select the sequence layers option, it is probably the only option that is active. The box that appears gives an option for overlap and tradition, for now, and certainly for a one frame per image sequence, leave the overlap at zero and with no transition. Hitting okay with create a composition with all the layers spread across time sequentially.
A single frame each is probably too fast, at 29/30 frames per sec that is rather faster than the eye/brain can process, unless you are a fly that can handle around a 100 frames/sec. Humans tend to max out at around 15/sec. That is why moving pictures, real or animated can use a frame rate that low and still create the impression of continuous smooth movement in the human perceptual system.
So let’s go back to the composition, insert the image layers and shorten them all to say 3 frames each. Again use the key assistant – and the sequence layers option with no overlap to spread the layers across time. This creates an image sequence with just enough persistence of each image to give a better chance that they are consciously perceived, while still passing fast enough to overwhelm any strong retention of an image because another is along before deep associations can form.
Using different lengths of time for each layer, and adjusting the amount and mode of the overlap can give a wide range of effects. Longer cross fades but shorter clear image durations [example] that can create a much smoother and less stroboscopically frenetic effect while still blurring the ability to grasp the individual views.
The key method to make these sequences easily adjustable is to create a sequence with a much longer time-frame than is intended for final use. Then time-remap the layer so that the slow transitions in the original edit are shortened, but remain smooth. This also allows the original sequence to have common effects applied, or individual adjustments which automatically are updated in the second composition
I expect that others with more experience will know other, and perhaps more elegant or flexible ways of achieving this effect. I hope that if anyone does have a suggestion or question they will comment on the blog and share their knowledge, or query. But I hope that for those like me trying to get to grips with the myriad possibilities within the AE video software, this description of how found a way to create the effect has been of some use. Or even better someone more expert in these matters can show me neater tricks…