Beta memo: at this time the forums and insider use two different registration and login systems. We're working on unifying the process, so if you register with your same e-mail on the forums and insider we'll merge your accounts later. To access the forums please use the login below. -Thanks.
Results 1 to 6 of 6
  1. #1
    Join Date
    Mar 2012
    Posts
    3

    Default Nuke merge not working

    When you convert a image say of a live action plate on blue screen bg to b&w and then subtract it from the original image you get a really black and blue image, then add it to the original again and you get a hires super saturated image, If you do it in Photoshop it works perfectly when I do the same thing in Nuke nothing happens but ever so slightly more saturated but no where near the same even the subtracted image looks lighter in nuke. any ideas

  2. #2
    Join Date
    Jun 2004
    Posts
    18

    Default

    Can you show an example of your images, as this is working for me. I can imagine that this has something to do with the values in your plate. Nuke calculates everything in 32bit floating point whereas PS does work in 8 or 16bit as well. So math operations look completely different in 8bit, when values are clamped at 0 or 1...keep that in mind.

  3. #3
    Join Date
    Mar 2012
    Posts
    3

    Default

    http://imageshack.us/photo/my-images/821/83343414.jpg/

    RAW FILE: http://uploading.com/files/85b4f9bb/ccm436.b2.1.exr/

    I apologize about the size but I assume you want the raw file.

  4. #4
    Join Date
    Feb 2011
    Posts
    17

    Default

    Did you set your read nodes to out put the right color profile for the footage? If you don\'t your math operations will be incorrect and give you unexpected results like the one you are mentioning.

  5. #5
    Join Date
    Jun 2011
    Posts
    18

    Default

    Quote Originally Posted by nathanfx View Post
    Did you set your read nodes to out put the right color profile for the footage? If you don\'t your math operations will be incorrect and give you unexpected results like the one you are mentioning.
    Very true, also Photoshop does all of its math in sRGB, while Nuke does its own in linear. In theory throwing a linear->sRGB before your color ops, and then going back sRGB->linear afterwards should give you the same thing you see in Photoshop. Photoshop\'s layer blending modes are a bit esoteric though, and don\'t perform exactly like those in Nuke....

  6. #6
    Join Date
    Mar 2012
    Posts
    3

    Default

    Seemed to be the problem thanks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •