How come hit film cant do imaginary colors?

CalebKCalebK Website User Posts: 435
Ok, i have been thinking about mocha pro that i just bought.  It is totally worth it but i would like to have a way to use all features with hit film.  I have been thinking about having mocha render in a color over a space that is a mask.  That way in hit film hit film can chroma key the mask and apply it properly.  That leads me to the question.  Through RBG values how come you on a computer cant make a fake color? Put in some combination that isn't on a color wheel... or even add another value.  Yes the computer wouldn't be able to display it but it could replace it with a real color when it shows you it.  Then you could just point chromakey to the imaginary color and it wouldn't have to do as much work.
Why wouldn't this work?


  • rgbiirgbii Website User Posts: 965 Just Starting Out
    edited June 2014
    Basically you described an alpha channel. It's a separate channel used to define the transparency of each pixel, however, you don't always have to have a true alpha channel to get the same effect.
    When bringing over rendered shapes from mocha pro, create a composite with your original video, add the rendered shape video from mocha pro (put it below the original), then add the 'Set Matte [Layer Only]' effect to the original video and select the mocha pro rendered video as the Source Layer for the effect. Select Luminance as the Matte Source.
    If you happen to be using a video with a true alpha channel, it has an option for that too (I think it's the default).
  • Triem23Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 18,270 Ambassador
    edited June 2014
    Theoretically, no reason.
    Practically, Chromakey was originally developed to work with actual footage with real colors. Adding "imaginary" color support means going off industry-standard RGBA (Red, Green, Blue, Alpha) color space, thus creating a color space no other program can read, and adds another byte (at least) to each pixel, increasing filesize and increasing computer overhead for something of very limited value.
    And, since you can already key by color, luma, alpha and or difference, I don't quite know why one would want to create a non-displayable color space.
    On the other hand, if you keep learning coding, maybe you'll create that tool and it will be fantastic.
  • AxelWilkinsonAxelWilkinson Staff Administrator, Imerge Beta Tester, HitFilm Beta Tester Posts: 5,242 Staff
    Any color system is limited by the number of bits it uses.  Standard, 8-bits-per-channel color, allows you to fit 256 unique values into each channel.  thus, each of the Red, Green, and Blue channels can contain a value from 0 to 255.  The specific values mix together to create the final color you see.  With 8 bits, there are only 256 available spaces, so you can't use any values outside that range, unless you switch to a different color depth.  And since every available value is used in the "real" colors that are available, there aren't any values available to make "imaginary" colors.  Anything lower than 0 will still just be black, and anything higher than 255 would still just be white, as the values will get clipped to those limits.
    And to define areas that are visible or not, alpha channels are already an effective, established method of doing so using greyscale, as rgbii mentioned.
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