Converting a non-LWF Diffuse Color to its equivalent in LWF Gamma 2.2

First topic message reminder :

Did any of you encounter washout color of material when using LWF Gamma 2.2? This happens when we merge 3D models to the scene which were not color corrected, or in other way they were made without using LWF Gamma 2.2. Example are 3D cars from *****MOTION haven't we notice it, they look washout in LWF.

So, I made this tutorial on how to convert the diffuse color from a non-LWF to its equivalent color in LWF Gamma 2.2.

FIRST METHOD USING VRAYCOLOR

Here is an example of diffuse color without Gamma/LUT Correction having an RGB value of 255,100,100. Look closely on the color.


Now we have tick the Gamma/LUT Correction with Gamma 2.2, Affect color selectors, Affect Material Editor, input Gamma 2.2, output gamma 1.0. We use the same RGB values 255,100,100. We notice the color changes, this is due to the gamma 2.2, checking the Affect color selectors & Affect Material Editor.


We make another material. Click the diffuse and selecting VrayColor.



In the VrayColor, we put our RGB values 255,100,100 or just copy & paste the color. In gamma correction select specify & gamma value of 1.0 (see image below).


Now we will correct the color by changing the gamma value of 0.4545. This is the invert of gamma 2.2. As we can see the color changes. The RGB value 255,33,33 is the equivalent of RGB 255,100,100 in non-LWF.


Comparing our results, we can say that they are the same color but differ in RGB values.


We copy the result color in VrayColor or manually typing the RGB values. This our final result, the equivalent RGB value of diffuse color from a non-LWF.



We only use the VrayColor to serve as a Color Calculator of RGB's.


SECOND METHOD USING VRAY COLOR CORRECTION

We use the same sample RGB value 255,100,100. In the diffuse color, apply ColorCorrection.


In the color slot of ColorCorrection, copy & paste the color or you can type it manually but express the RGB values in decimals. Divide the corresponding values by 255. For our example, we express it as RGB 1.0, .392, .392 .


Preview of RGB 255,100,100 or RGB 1.0, .392, .392 without color correction.


Now we go to the lightness tab, click advance & in the Gamma/Contrast put the value .4545 (the invert of gamma 2.2). We notice the color changes. This the equivalent value of RGB from a non-LWF.


The second method is the easiest way. Now, we can start converting all our stock models. Lol!!!

Thank you for spending time reading this tutorial... Ciao!!!!!!!!!!!!!!!

v_wrangler wrote:Well I have yet to know till I render and check. Safest way is to convert the old file first (via the shortcut I mentioned) before merging to an LWF setupped file. Don't you think so?

So, you mean sir you will have to tick linear workflow in the color mapping from the old file. Then you merge in it to the scene with LWF setup, I guess it will carry those settings in the old file because in the current setup (LWF) you will not have to tick the linear workflow in the mapping. If we try to tick that (linear work flow) it will mess up our render.

actually, all you need to do is paste the RGB value of the color from the orignal non LWF file to the swatch sa Vraycolor map. Let Vray color do the rest. as long as you set the gamma to 1 (which is the gamma of the non lwf file), then it will render the same color as that of the non- lwf file.

No more of those making another material and pasting the new rgb values.

Isa pa, vraycolor serves that purpose. Its not just a calculator as you mentioned.

salamat master

great stuff kabayan!
.4545 value is still thoeretical cause there is no range of equal value on gamma but its the closest.

dont or never tick (linear work flow) as it is almost the same as burning your gamma on the environment and revert it again in zbuffer but not in a srgb format (worse, im not quite sure why they put it in there). just let it 1:1:1 openexr is much accurate because it preserves values of bitmap and resolution.

julcab wrote:great stuff kabayan!
.4545 value is still thoeretical cause there is no range of equal value on gamma but its the closest.

dont or never tick (linear work flow) as it is almost the same as burning your gamma on the environment and revert it again in zbuffer but not in a srgb format (worse, im not quite sure why they put it in there). just let it 1:1:1 openexr is much accurate because it preserves values of bitmap and resolution.

masyadong mabigat ang dating di ko naintindihan Di ko naintindihan yung comment mo about burning gamma to where so I will reply about it pag nagets ko na ibig mong sabihin.

The .4545 value is the closest. And its a standard value cause you do not and will not see the integer difference unless you are compositing for float images.

Anyways, the linear workflow tickbox is there to automatically convert rgb values of old files. That simplifies the conversion that the thread starter wrote about. Don't fear, just know when to use it.

masyadong mabigat ang dating di ko naintindihan Di ko naintindihan yung comment mo about burning gamma to where so I will reply about it pag nagets ko na ibig mong sabihin.

compile ko yung reference ,study at comparison samples ko po medyo madami^^ mostly sa google lang din master tsaka konting experiment sa cs. but i was wondering there must be a reason why they didnt make LWF standard in 3ds max rather than going all the trouble?.



The .4545 value is the closest. And its a standard value cause you do not and will not see the integer difference unless you are compositing for float images.

yup^^

Anyways, the linear workflow tickbox is there to automatically convert rgb values of old files. That simplifies the conversion that the thread starter wrote about. Don't fear, just know when to use it.

hindi ko kasi natry magexperiment sa linear workflow na dbox based lang din sa google. so diko pa nagrasp talaga. experiment ako ng comparison soon. anyway thanks master for the added info on the topic.^^

thanks for the info sir wrangler i'll try to do what you have said.. there are many ways how to solve this things as long we arrive on the same output.. there are many interpretation of LWF on the internet, generally some of the members here find hard time to understand.. thanks for your undying inputs and comments...

@julcab.. regarding the tickbox for the linear workflow in color mapping, it is applicable only for old files non-LWF...

mokong wrote:@julcab.. regarding the tickbox for the linear workflow in color mapping, it is applicable only for old files non-LWF...

ive tried the linear worflow tab (gi colormapping: gamma 2.2 with linear workflow ticked) with my old non-lwf scenes and output is not quite the same as the real LWF preset should look like. LWF dialog box is more like a color mapping preset and not rig in the gamma preference itself which means it is only burned after the computation of the gi or after the image is being rendered. It doesnt serve it purpose even though it is indicated in the vray docs(fake lwf dialog box). In short it is like a color map preset.

as what I've read in some websites they always disregard this option.. confusing... anyway, thanks for the info...