More gamma stuff and linear workflows

[thablanch]

Did somebody found / did a script that changes every bitmap input from default to 2.2.
That would change a scene from method I to II in a few seconds.

[joconnell]

Yes I did a colour correct script a while back - doing a tweak or two on it, it'll be back later tonight.

[Infrared digital]

Has anyone noticed when changing to LWF that avi's render darker ?

[tricky]

Right then. I am trying again (for the 132nd time) to get to grips with all this LWF stuff. I am using Vlado's M2 method.

In the VFB the image looks dark. If I tick on the 'Display colors in sRGB space' it looks fine.

Now, when I save this image as a jpeg I get the dark image when I open it in Photoshop, even though I assign the sRGB profile. Here it is:


If I tick on the gamma override and set it to 2.2, I get this (which is the same as the VFB image with sRGB turned on I think):


Isn't overriding the gamma when I save the image in effect 'burning in' the gamma? Correct me if I am wrong, but I don't want this to happen do I? I should just be able to *view* and work on the image with a sRGB (or Gamma 2.2) profile in Photoshop shouldn't I?

I am surely doing something wrong.

[tct70]

When I tried LWF (without much success - ran out of time) I remember saving the image in the Vray FB as an EXR file. I opened this in photoshop and it looked the same. I was then able to save a jpeg that also looked the same.

[jow]

Looks right to me Tricky,
If you save the image in 32 bit then don't burn in the gamma ( save at gamma 1.0 then in PS change the gamma to 2.2). If you are saving as jpg (8 bit) then do as you are, override the save rollout to 2.2. Or just set the gamma to 2.2 in the colour mapping parameter.

[tricky]

OK - thanks guys. It is starting to click (although I think I have said that 17 times before!)

[DaForce]

Simplest way to use LWF.. is setting max gamma to 2.2, use gamma correct color mapping set to 1.0/0.45454 and render to the VFB and save as 8bit.

If you dont need any post work, or any further color corrections that just the simplest way to do it. Not the most flexible no.. but simplest yes

[ene.xis]

ermmmm....
use any color mapping....and adjust the gamma value in it to 2.2

right Daforce?
1 - 0.4545 was before the rcandidates....

[DaForce]

ahh yeah I believe so.

[ene.xis]

[tricky]

We have just taken delivery of new workstations and we have opted for HPs 30" flat panel monitors over the 22" CRT displays we have had up until now. We are now at the point where we need to profile and callibrate the screens with other flat panels around the office.

We use the MonacoOptix XR (Pro Edition) calibrator to do this. When we launch the application, it asks us for the desired Gamma, but only gives an option for 1.8 or 2.2

Now Vlado's first post says that for LCD (TFT) panels, it would be better calibrating for a Gamma of 1 as they act more linearly than CRT displays. How do I go about this?

[Robur]

Hi Tricky,

I've been wondering how to calibrate to 1.0 as well?....

The simplest solution I have found so far is to have my LCD calibrated to 2.2.... render out as you are doing..... open the 'dark' image in Photoshop and under exposure set the gamma to 0.4545 (1/2.2) - job done.

The result:



Cheers.

[Rhys]

Ok this will be my first post on this forum.

I've been reading about lwf and have read the other topics and think I understand but may need a little helping hand.

What I understand is that to achieve the correct setup. Is using a hardware or software calibrator to set my monitor to a correct 2.2 gamma setup with 6500k whitespot.

Then in max i'm setting the gamma to 2.2 so that the max fb shows the correct result. Then also ticking affect material editor so that also showing the true gamma corrected color.

This is where i'll break down into 2 sections. difuse colors and materials (jpg tiff ect.)

If i was given an rgb color from a client. Can i just enter this into the normal rgb channels and expect to see that same result? Or do i have to use the color correct plugin which only works for max 9 32 bit at the moment. To acheive that rgb color in the true gamma of 2.2 ?

With the materials setting. To work in linear space in photoshop if i take one of my materials and use the exposer control and set it to 2.2 whilst using an srgb color space. This has now made in linear correct?

So instead of having to do this to every image we use the input gamma and set it to 2.2. Now if i set it to 2.2 and bring in the material and dont have affect material editor ticked. The map comes in and looks the same as it does in photoshop with the 2.2 gamma applyed. If i now turn on affect material editor the material becomes more brighter and looks like the material in photoshop with out the gamma applyed. So which is linear workspace ? and how would i create textures in photoshop working straight in linear workspace ?

Ok so after that I render in the vray fb with linear multiplier set to 1 and 1. I've noticed that there is a gamma option in here as well. If i set that to 2.2 wouldnt that burn the curve into the image ? and is affect background ticked or not ticked? Thats off track just noticed it there.

What i'd do now is render in the fb with and apply the curve to to preview the render. and then save out as a 32 bit image with floating point, and then edit this in photoshop to bring the exposer down to 2.2. When opening in photoshop should I be in srgb monitor calibrated profile ?

I know if i didnt want to have to do that i could use gamma correcting and set a bright = 0.4545, dark = 1.0 and save out as 8bit with the curve burnt in. Then i can just use my monitor profile and it will be displayed correctly. This is probably the better solution if i want to do editing in photoshop as not all features are usuable at 32bit mode.

Ok I think thats it for now. Trying to output into combustion as well but i'll save that one for another day once i've got this workflow sorted first.

Hope i've understood it enough!

[Shoey]

Right then,

I think i'm starting to understand how to go about setting up LWF but still not sure why i would?

So far i've calibrated my monitor to gamma 2.2, enabled gamma/lut in max, changed that to 2.2 as well, then ticked affect colour and affect materials. (is that right?)

I can see from a before and after render that there is more setail showing up in the shadow areas, but there also seems to be a lot more noise, is this right? Also, some glossy highlights have now been made more sublte than before?

Also, if you are going to render an animation over a netwrok using backburner, does every machine need to be setup for a LWF or can i get away with only having my workstation converted?