Author Topic: picker RGB / sRGB  (Read 4244 times)

2016-10-25, 23:59:08

astudio

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What does it mean "Mono" in pixel information? Is it luminosity value in RGB space? Can I get this info in sRGB?
Is there any way to get average luminosity value of bitmap in preview in material editor? May be some plugin?

PS. How to get this color picker? Is it from daily build?
https://forum.corona-renderer.com/index.php/topic,13570.0.html

2016-10-26, 09:44:32
Reply #1

romullus

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I think mono is R+G+B/3.
You can change default colour picker there: customize>preferences>general>color selector>Corona improved picker
I'm not Corona Team member. Everything i say, is my personal opinion only.
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2016-10-26, 10:26:41
Reply #2

Jadefox

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Wait hold on a sec..
Can anybody please explain the above to me.
Lets say for example I want to make a wood material , do I take my colour picker
and pick the colour on this chart and paste into albedo slot for example and similarly then for the
gloss and reflection ? I have just kinda always fiddled with these setting until it looks right.

2016-10-26, 10:43:44
Reply #3

astudio

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Wait hold on a sec..
Can anybody please explain the above to me.
Lets say for example I want to make a wood material , do I take my colour picker
and pick the colour on this chart and paste into albedo slot for example and similarly then for the
gloss and reflection ? I have just kinda always fiddled with these setting until it looks right.

Sure. It's a goal. :)

http://www.marmoset.co/wp-content/uploads/materialref02.png

2016-10-26, 10:46:43
Reply #4

astudio

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I think mono is R+G+B/3.
You can change default colour picker there: customize>preferences>general>color selector>Corona improved picker

Thank you Romullus. It's great.

Is there a list of all improvements which we got and don't know about? :)

2016-10-26, 10:53:58
Reply #5

astudio

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2 Jadefox.

There is no need to take RGB value for albedo, cause you have your own wood bitmap. But luminosity of your albedo bitmap you may change according to this chart. And of course reflect and specular you may take as is or, if you use bitmaps for them, to adjust their luminosity too.

2 all

My question is about how to check average luminosity of bitmap inside max... Especially after color correction...

2016-10-26, 11:20:12
Reply #6

astudio

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Another question:

In color catalogs we have LRV number  (Light Reflectance Value) for every color. What does it mean in Corona material terms?

2016-10-26, 11:23:05
Reply #7

Dionysios.TS

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This is why the Reflectance and Transmittance values we fount in the Material Editor are so useful as they do this job "automatically", They give Avg and Max values for each plain color or bitmap used.
But with Corona don't work. I always used them with Iray and MR years ago.
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2016-10-26, 12:23:12
Reply #8

astudio

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This is why the Reflectance and Transmittance values we fount in the Material Editor are so useful as they do this job "automatically", They give Avg and Max values for each plain color or bitmap used.
But with Corona don't work. I always used them with Iray and MR years ago.

Hey!!! It works when you enter into the bitmap and turn off "show end results".
Great !!!!!!!!!

2016-10-26, 12:35:42
Reply #9

Dionysios.TS

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Yes but it doesn't calculate the reflection and refraction values + the diffuse numeric values as well. By doing this in the bitmap level it sees only the bitmap and that's it.
In the other hand Iray does! I remember I asked to the Iray dev team this and in a few days was all setup! :)
RPBW Responsable d’Imagerie / CGI Manager
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2016-10-26, 12:48:08
Reply #10

astudio

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Never used it before. If I understand right, I get the luminosity value of bitmap here, so I can play with output or color correction to get needed value for my reflection, refraction, glossy slots etc.

2016-10-26, 13:36:28
Reply #11

Dionysios.TS

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With the Colrona shader you miss the influence of all the root values: Reflection, refraction, self illumination ecc.
The Iray Material for example when it gives Reflectance and Transmittance values takes in count all of the values in the material and I think this is very useful and great!

In any case here is how it works (very simple):

To be physically corrected your Reflectance value must never go over 80% / 85%. A white paper, which is the most white element we have in the real world, after the snow, should use 80% of Avg. value. A white paint wall is around 65% / 70% and so on...

What is the Reflectance value? Very simple: A paper (Avg. 80%) receives 100% of luminosity and reflects 80% of it in the space.

The Avg. value represents the average value of your bitmap while the Max value reads the most bright pixel of it. This is very useful as you may have a 65% Avg. value while some pixels are positioned to a 90% Max. and this is not ok. In this case you should go in Photoshop and lower the bright levels of it till you read a lower Max. value.

It's a shame we can't use this tool in Corona as it can help a lot to avoid easily albedo problems.
RPBW Responsable d’Imagerie / CGI Manager
& freelance 3D Artist.

Personal Portfolio: https://evolvia-imaging.com

2016-10-26, 14:09:29
Reply #12

Fluss

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+1 would be a great tool to review shaders

Edit: we should make a feature request for this