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"gamma correction" in DS 4.6

jakibluejakiblue Posts: 7,281
edited December 1969 in The Commons

What exactly is this "gamma correction" in the render settings in DS? I've actually only just taken notice of it :blush:

I"ve noticed lately a few posts where people are saying turn it to on and change the settings etc, but I'm wondering what exactly does it DO. Does it increase render times? Does it really make a difference? what instances would you actually use it? All the time, sometimes?

Comments

  • Lissa_xyzLissa_xyz Posts: 6,116
    edited March 2014

    The gamma control in DS is bass-ackwards from what you would normally think it is.

    The way Richard confirmed it for me was If the gamma toggle is off (unchecked), DS assumes the textures aren’t gamma-calibrated, but with gamma on (checked), DS assumes they are. So it’s more of a Yes/No than an On/Off, with the question being ‘are the textures gamma-ready.

    http://www.daz3d.com/forums/discussion/30106/#446213

    I use Poser's gamma correction, but I don't use Daz Studio's.

    Here's a more in-depth thread regarding gamma correction that you may want to strangle me for later lol
    http://www.daz3d.com/forums/discussion/22310/

    Post edited by Lissa_xyz on
  • jakibluejakiblue Posts: 7,281
    edited December 1969

    Right. Well. Um. I didn't understand a single word of that thread. LOL!!! I think I may end up leaving the gamma thingy in DS where it is and not touch it, cos it's straight over my head.

  • Lissa_xyzLissa_xyz Posts: 6,116
    edited March 2014

    Basically, if it's off, DS will calibrate your render (maybe the texture maps? I don't know), if it's on, it won't. lol

    It sounds backwards, but that's how it was explained to me. I just leave it off since I postwork everything anyways.

    Post edited by Lissa_xyz on
  • jakibluejakiblue Posts: 7,281
    edited December 1969

    hmm I postwork everything too. I love me some postwork. LOL.

  • RuphussRuphuss Posts: 2,631
    edited December 1969

    never touched this before
    now 2 examples on and off
    off is a lot darker but more colourfull

    whos_there_gamma_off_02.jpg
    1920 x 1080 - 2M
    whos_there_gamma_on_02.jpg
    1920 x 1080 - 2M
  • SzarkSzark Posts: 10,634
    edited December 1969

    if you really want to understand Gamma Correction then start here http://www.daz3d.com/forums/discussion/18364/P120/#559539 and read the next 3 or 4 pages.

    ruphuss yes it will be lighter if you didn't adjust the lights. ;)

  • RuphussRuphuss Posts: 2,631
    edited December 1969

    Szark said:
    if you really want to understand Gamma Correction then start here http://www.daz3d.com/forums/discussion/18364/P120/#559539 and read the next 3 or 4 pages.

    ruphuss yes it will be lighter if you didn't adjust the lights. ;)

    I just wanted to show the difference between on and off with the same lighting

    and yes I will read that thread
    I hope it enlightens me

    playing around with gamma-on I have to learn everything new because of the totally different reaction
    of the surfaces

  • SzarkSzark Posts: 10,634
    edited December 1969

    I appreciate that ruphuss and it illustrates it nicely and yes surface react differently when Gamma correction is ON which is the whole point of it and it works better with physically correct lighting that have the inverse square law of light, like dz lights not the ones in the Create menu but the ones in Light Presets, thought the dzpoint lights have an issue with soft shadows not being soft. Uber and AoA's new lights are also good for this too.

  • Richard HaseltineRichard Haseltine Posts: 100,778
    edited December 1969

    Vaskania said:
    Basically, if it's off, DS will calibrate your render (maybe the texture maps? I don't know), if it's on, it won't. lol

    It sounds backwards, but that's how it was explained to me. I just leave it off since I postwork everything anyways.

    There are two settings -

    a gamma value, which is the same as the gamma value in the Photoshop Levels dialogue or equivalent; it shoves the middle range of tones towards the brighter end (for a positive gamma), stretching out the darks and compressing the lights without changing black or white, so that more shadow detail is visible.

    A gamma correction button which when set to on reverses the (assumed) built-in gamma 2.2 adjustment of colour maps - if you have maps that were made to look right on a monitor then they are probably already implicitly gamma corrected, so applying another levels adjustment on top of that is just going to wash them out horribly. Setting gamma correction to on will, somewhat intelligently, correct for that by applying an opposite levels adjustment to the diffuse and other colour maps (while leaving things like bump and opacity maps alone) before passing them to 3Delight, which should avoid the problem.

  • Lissa_xyzLissa_xyz Posts: 6,116
    edited December 1969

    So, ticking the gamma button (and I'm assuming setting the slider to 2.2), will not only correct uncalibrated textures, but also detect the calibrated ones, account for that, and avoid the wash-out look?

  • Richard HaseltineRichard Haseltine Posts: 100,778
    edited December 1969

    Turning the button on will remove the assume gamma from the diffuse and other maps likely to have been created by eye, as opposed to control maps like bump and opacity (there can be problems where the same map is used for both a visual and a control map). You can override the auto-correction using the Image Editor command in the texture picker menu (it's just under the command to launch the Layered Image Editor): 0 is adjust automatically, any non-zero value will be taken as the gamma embedded in the image.

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