I've been trying to get certain paint colours (RAL) to show up correctly in my PV360 renders and after looking over the forum I had found some other posts where people were asking the same questions but without any suitable answers. After alot of testing I think I've found out why, but I wanted to see if my thinking is correct.. Or maybe I'm way out to lunch! SW is not my typical rendering platform as I've trained mainly in full fledged animation software (AD) but for some situations it would be nice to just use SW for a quick render.
Background info:
1) The rgb values that you see in online RAL libraries are sRGB values (https://www.e-paint.co.uk/lab-hlc-rgb-lrv-values.asp?cRange=RAL+Classic&cRef=RAL+2009&cDescription=Traffic+orange) which display correctly on a sRGB monitor, gamma 2.2).
2) Rendering software require linear colour values for their algorithms. Most rendering software has an interface that allows you to pick a sRGB value but the software converts it to linear values at render time. Or maybe more simply the display colour shown in your viewport is the sRGB value but at render time it uses the Linear RGB value.
3) PhotoView 360 gamma values is set to 1.6 by default. Why? Half way between 1.0 and 2.2. Seems like 2.2 makes more sense as this is the gamma value needed to display on our monitors.
So I picked an assembly, coloured it with my RAL paint colours (sRGB values), set Gamma to 2.2, setup a scene light with a camera and hit render. Wow really unimpressed. The colours were way off! Most notably the RAL 2009 Traffic Orange, RAL 5001 Green Blue, RAL 6012 Black Green and RAL 7040 Window Grey. Now I tried the default gamma of 1.6 and adjusting the lighting but no matter what I did the colours didn't look correct.
After doing some more research I discovered that I could use Modo materials within PV360. I downloaded the RAL colours from foundry.com and brought them into SW. First thing I noticed was the message saying that the colours in the viewport would be darker (can't remember the actual message). Changed out the appearances, hit render and wow, WAY better. These look like the correct colours. (don't have a render).
So this got me thinking about sRGB and Linear RGB. Maybe SW doesn't have a way to display a sRGB colour but use a Linear RGB for rendering. Thus I manually converted all my sRGB values to Linear RGB and reapplied my appearances. This resulted in VERY dark colours in the viewport that don't look correct.. Hit render and voila the render looked almost identical to the Modo appearances.
Example conversion:
RAL 2009 sRGB: 226,84,0
RAL 2009 Linear RGB: 194,23,0
Thoughts, comments? If my above thinking is correct then it looks like I need two sets of appearances; one for display and another for renders. Then some macro that quickly swaps appearances when I need to do a render.