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View Full Version : Color on surface of object ( in IPR Octane ) different then in color picker.



Carlo_Jongen
09-12-2014, 11:11 AM
Why is it that my color in the color picker looks different from the color on the surface in Octane IPR?
- IPR Response set to Linear.
- CS in Preferences are all in Linear space.
- Camera Imager Response set to Linear.
- Lights and background are white.
Anything I've overlooked?

124205


Freelance Lightwave Animation at www.c3d.be

Snosrap
09-12-2014, 08:50 PM
I think there are some issues with the color picker outside of the use with Octane. I don't think it switches from linear to sRGB when it should.

Carlo_Jongen
09-13-2014, 03:26 AM
I’ve noticed that the color will go more towards the color of the color picker if you turn off ( disable ) the “Normalize” in the Light Panel Properties. It’s still a bit of but it matches more. Don’t exactly know where the “Normalize“ stands for.
I’ve quickly made an overview of screen caps to clarify my settings in the next link:

http://www.c3d.be/Octane/

I would like to render the next project ( product placement animation ) with Octane but I need the colors to match closely to the pictures they send me. So any tip on getting Octane to work for me is welcome.

adk
09-13-2014, 03:41 AM
Are you working in linear space in LW to begin with? You might be applying gamma twice hence the lighter colour.

Sorry.... Just read your other post, seems you are. Weird as I've not noticed this behaviour / discrepancy before.

juanjgon
09-14-2014, 05:21 AM
It is hard to say ... in a linear environment (Octane with Linear response and 1.0 gamma, white background, no lights, no GI bounces, etc), and all LW color space settings disabled, the colors should look similar, but anyway in a real scene all the settings (lighting, environment, the GI bounces, the tone mapper, etc,) makes hard that a picked color is what you get in the renderer.

Perhaps you only need to adjust the exposure time in your scene to get a correct match between the color picker and the rendered image, but in a real scene this workflow is going to be hard ... The physical nature of Octane makes hard that a picked color could be rendered like the one you pick. Octane is an interactive renderer, you only need to adjust the colors in real time to match your reference plate, but not using the color picker, you need to try to match your reference using the rendered image with your scene lighting, environment, tone mapping, etc.

Anyway it is true that I can't control the color picker response. The plugin gets a linear not corrected color, so if you work for example with any kind of tone mapping in Octane, the color you pick can't match the rendered image, even if you have only a white environment.

-Juanjo

vonpietro
09-14-2014, 10:47 AM
there is like 9 places you can change your color space in the cs options tab.
i had one linear and one srgb and for a day could not figure out why my color picker was off when i tryed to pick a color from the screen.

when i checked my options i had a mix of srgb and linear because i was discovering the srgb color space a few days before and forgot to go back to linear.

so hit, o, and check your color space options =) (just as an aside, not releated to ocatane color picker thing)

spherical
09-14-2014, 04:17 PM
This CS thing is doing my head in. So, if you are working in LightWave and using its internal renderer, you use sRGB CS but when using Octane, you switch LightWave's CS off to: Disabled (Linear)?

lightscape
09-14-2014, 09:55 PM
It is hard to say ... in a linear environment (Octane with Linear response and 1.0 gamma, white background, no lights, no GI bounces, etc), and all LW color space settings disabled, the colors should look similar, but anyway in a real scene all the settings (lighting, environment, the GI bounces, the tone mapper, etc,) makes hard that a picked color is what you get in the renderer.



In octane do we need to linearize images to 0.4546 via the octane image node?
There's no global setting to linearize in octane so not sure if we need to this per image.
Setting lightwave to cs disabled means lightwave is feeding images to octane render that are not linear. Or not?
In kray it has its own linear worfklow master plugin. So lightwave cs is disabled, kray handles the linear workflow so the render is linear workflow. Only drawback is it only works on images not on colorpickers but its a global setting for images so no need to do it one by one.

juanjgon
09-15-2014, 01:53 AM
Octane loads the image files itself, all the Lightwave image settings or gamma values are to used at all. The Octane image texture node has a gamma parameter to correct the 8 bits not linear images. By default this value is 2.2 to linearize all 8 bits images that have a 2.2 gamma. This gamma value should be 1.0 for linear or HDRI images.

The output gamma is controlled by the render target imager node. In this node you can set a film tone mapping preset, or if you leave it in linear mode, you can set a gamma value for your render image. Usually the Octane users are working with a tone mapping preset, leaving the output gamma value to 1.0 (the tone mapper presets also have a gamma correction).

This is why all LightWave color space functions should be disabled. All gamma (for input images and for rendered output) and tone mapping settings are controlled by the Octane plugin.

-Juanjo

spherical
09-15-2014, 04:21 AM
This is why all LightWave color space functions should be disabled. All gamma (for input images and for rendered output) and tone mapping settings are controlled by the Octane plugin.

But then aren't things like LW Color Picker incorrectly displayed or does the plugin control it?

juanjgon
09-15-2014, 08:36 AM
But then aren't things like LW Color Picker incorrectly displayed or does the plugin control it?

The problem is how to get a tone mapped color picker, for example a color picker that display the Octane Kodak or Agfa tone mapped colors that your scene could be using. The plugin can't control the system or LW color pickers, they only return the linear RGB color values you pick.

You should adjust your colors using the IPR, over the rendered image ... from my point of view try to pick a color to get this exact color in the rendered image is not a good workflow, there are a lot of things that can change this color (the tone mapper, the lighting, the global illumination, the ISO and exposure times, etc.) ... your only chance to pick a color and get this color in the rendered image is to work in perfect linear environment: linear settings, gamma 1.0, no tone mapper, pure white background or lights, etc ... but as soon as you introduce this object for example in a room with colored walls, the GI is going to change your color.

This is why the interactive rendering is so important, simple adjust the colors in real time until you get in the rendered image the tone you are looking for.

-Juanjo

Carlo_Jongen
09-15-2014, 09:33 AM
Hi Juanjo,

Thanks for joining this thread and giving your input to this issue.

I followed your tips for texturing and now I understand more how to work with Octane.
I've put up a test scene and bumped into another issue I couldn't figure out. Attached to this message is a screen cap from Fusion. It's an A/B compare. At the left side is an image rendered with Octane and saved automatically by LW after hitting F10 ( outputs an PNG image ). It feels like there is a dark filter on top of the render making the image darker and more dull and unsharp.
To the right is an Image rendered with Octane after hitting F9 and saving it manually to the same PNG image type. The image at the right side looks exactly like the IPR preview window.

I don't understand why there is a difference in the image output. It's like the image gets some kind of filter after it is saved out. But these renders should look the same when hitting F9 or F10. I can't seem to find whats going on. Any suggestions on where to look.

Thanks for your advice.

124279

spherical
09-15-2014, 09:34 AM
Cool. Thanks, Juanjo.

juanjgon
09-15-2014, 09:38 AM
Yes, render with F9 and F10 should be the same (if you save the F9 image after the render is finished, from the image viewer, not using the preview window save option) ... can you send to me the scene? ... I don't need the objects, only the .lws file to check it here: [email protected]

-Juanjo

Carlo_Jongen
09-15-2014, 10:07 AM
Hi Juanjo,

The problems seems to be solved. I've closed LW and loaded the scene file again. Did both F9 and F10 render and they both look exactly the same.

Greets,
Carlo