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double exposure



  • Hi,
    am looking for an interesting solution for doing a double exposure effekt in Isadora.

    I have 100 short video snippets and I want to use two od three player to play the snippets. All videos are HAP AVI alpha.
    I thought the best was to do this, is using the luminance key. Also build a cue, meaning cascading a few luminance key module brings interesting results.

    As I can´t (don´t) build a mask like in After effects, but I want to build the effect in Isadora in realtime without knowing which video is combined with which one I would like to make the form of double expore dynamic.

    Did anyone else already experimented with a double exposure effect?

    thanks for any feedback.

    frank


  • Tech Staff

    @inst

    Important is that you use videos with lots of contrast, ideally black and white video. Then you let the videos go through an "add alpha channel" actor, this ensures that black will be converted to alpha (it may also work without the "add alpha channel" actor, depends on your footage). Set the "projector" actors to additive. You can also play around with the effect mixer actor.



  • first: the effect you posted is called double exposure, but, as far I know, this name is unprecise. The real double exposure ( obtained with real films and so on) is reached just overlaping in additive mode two images.

    second: according to the video posted I've saw that the "main" image is taken in high key with a very poor gamma, so if your videos are not like that just add some effects in between to do it.

    third: i suggest you to play a bit with threshold actor and alpha channel


  • Tech Staff

    I was playing around before bed. Maybe something here will be interesting to you.

    >>>PATCH + MEDIA<<<



  • @michel

    Thanks for your feedback. - As a lot of my video snippet have been recorded outdoor - I have a lot of skies..,.,
    Which will deliver good contrasts. -



  • @maximortal

    Thanks.
    And yes I know, the double exposure comes for  the old analogue world - but I did not have a better word to explain what I am looking for.
    Nowadays it seems to be a trendy effect specially in digital photgraphy. - And thanks for the "treshold" hint.



  • @woland

    Thanks for your patches - I will try them out and experiment with additional modules and my footage.

    As always I really appreciate the quick feedback and hints for a specific howto question in this great Isadora community.