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Bad picture quality

VickanVickan Posts: 41
in The Commons

I have problems with iray Renders when I make dark images. They become grainy (to much noise). How do I fix it? Where is the setting to increase picture quality?

Size is 2560 × 1440 and i have iray settings at custom.

Can anyone help?

Comments

  • BeeMKayBeeMKay Posts: 7,019

    You have to increase the render time. By default, the render stops after two hours, no matter the quality. If the image is still bad, do not close the picture, but at the left side of the rendered image, a menu bar is hidden. There, you can increase the render time, and then hit resume, so you don't have to re-do the entire two hours the image already rendered. 

    if you set the quality settings to Off, and just increase the render time, dark images also render better, for some reason.

  • 3Diva3Diva Posts: 11,973

    Under your Render Settings and "Progressive Rendering", what are your settings at? I THINK (I might be wrong on this since I'm still pretty new to 3D art) but I THINK if you increase "Max Samples" that it might help. 

    I wish I could be of more help. I'm pretty new to rendering - I don't have that graininess issue though, so I'm happy to share my settings with you, to see if using the settings I'm using will help. Let me know. :)

  • nemesis10nemesis10 Posts: 3,790

    The other way is to do what moviemakers and photographers do; make the scene brighter and then darken it in postwork so that you have the combination of faster render times, little grain, and total control over the darkness levels.   

  • VickanVickan Posts: 41

    Thanks all! I try to inrease the render time. For this picture it was aprox 3 hours. What is "normal" render times for darker pictures?

  • VickanVickan Posts: 41

    What are yours settings at "Max samples" and "Max time"?

  • VickanVickan Posts: 41

    There are also a tab for "Rendering Quality". It stands on 1.0

  • nonesuch00nonesuch00 Posts: 18,729
    edited December 2016

    If you want to keep the shadows as you like the only good way is to increase the length of render time, increase the percentage to convergence, the quality of the render, and set the maximum render time (on my computer maximum is 3 days but yu can increase or decrease the parameterized limits in DAZ Studio if your like) and wait a long time.

    I tried the things others have talked about in this thread and other threads but ultimately those things weren't creating the lighting mood, even after adjustment in postwork that rending the lighting mood directly in iRay would give because of lost details.

    For indoor and outdoor at dusk and dark, you can set the Tone Mapping ISO value to 400 or 800 or those are pretty common film speeds to use in those conditions and so something the eye sees as plausible. Changing some Tone Mapping values automatiically changes other tone mapped values so it you really want to do as the prior posts suggests, the easiest way, and I've tried a lot of suggestions, some of which require a lot of adjustments and guessing and part renders and more adjustments and documentation and note taking just to track what you are trying and changing - not practical or sensibly reproduceable without copious notes on cause & effect of all the adjustments you make if you are not a trained photographer.  

    1. leave the lighting as is

    2. lock shutter speed

    3. lock f-stop

    4. lock Film ISO

    5. change only the exposure values - for exposure value, values closer to one will make the scene very bright and over-exposured - getting rid of that noise but only because it's too bright for you to see and because much detail is lost; or higher values make renders darker and more noisy. The people that do that render at 4K (UHD) resolution and then reduce image size to FHD or HD or other small sizes and adjust the brightness in GIMP or Photoshop or other SW. Reducing the size of the oversized image has the effect of eliminating much of the need for the details that were lost by rendering the image over-exposed and anti-aliasing on image reduction creates the illusion of rendered details.

    Post edited by nonesuch00 on
  • 3Diva3Diva Posts: 11,973
    ivossite_dot_se said:

    What are yours settings at "Max samples" and "Max time"?

    My Max Samples is 5000 and my Max Time is 7200 - but my scenes are usually pretty brightly lit. 

  • VickanVickan Posts: 41

    I adjusted them now to 15000 and 259200. I hope this will fix the problem.

    Thank you nonesuch00 for your detailed answer!

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