Lately (maybe started around 11/15/25 or so), I am getting a difference in exposure between the VRay frame buffer and the image once saved from it (jpeg in my case but it doesn the same thing in other formats). The VRay buffer looks good to me, but once save, appears blown-out (overexposed) by an F-stop or maybe even 2, in the saved image. Anyone experiencing this?
Nothing really, I can’t exactly pin-point when this started so I am not sure if maybe an update in VRay, NVidia driver… not sure… I was just curious to know if I was alone on this. I did search the forum and found another post (2021) about exposure but not really the same issue (wrong settings). Any input is welcome - Cheers!
What version of SketchUp and Vray are you using? What operating system and graphics card? Your profile says you are using SketchUp 2018 on Windows 10. Is that all still correct?
If things were working normally and suddenly don’t, proper troubleshooting method is to look at what changed right before. As @mihai.s suggests, changes in the way you are working or setting changes in Vray are possible things to look at. Another would be a graphics driver update from a Windows update. You could go to the graphics card maker’s site to get and install their latest drivers. That might help.
I use SU 2018 but that’s on an older machine. The issue I have in on an Alienware M-18 R1 with NVidia GeForce RTX 4080, runining Win 11, Sketchup 2025 (26 was giving me too much grief) with classic graphics engine (new one was crashing several times a day…), and VRay is 7.20.02 (but problem stated when still using prior version (7-20-01). My work around the issue is render a bit underexposed but if I could figure out what is causing it and fixing, that would make my life easier 
It would be helpful if you add that information to your forum profile.
Have you tried contacting Chaos Group support about this?
lol, working on updating my info right now. I haven’t contacte Chaos yet but will shortly. Thanks!
Can you share a file where this is happening?
This is the scene from the VRay buffer.
and once saved as jpeg or png, this is what the same scene looks like:
… any idea what could cause this? I haven’t changed my usual settings, juts one day was fine (WYSIWYG) and next day, difference in exposure…
Can you share the .skp file here? - or create a duplicate and delete a bunch of things from it and share that.
The settings for vray are stored inside the file so it should be easy to replicate
Sure - I will shortly but on a tight deadline right now.Thanks!
FIXED - Doing more digging in VRay’s new interface I saw that there is a new layer (at least, new to me) - Filmic tonemap - that, once adjusted, allows me to get the same result both in the VRay buffer and on the jopeg file saved from it.
Hope that will help someone
I was going to suggest that - but the last person I suggested that to said it didn’t help at all so I resisted. Typical 
For reference the setting that a normal human wants to use here is to simply set it to either the John Hable (HABLE) Tone mapping or the Oscars.org | Academy of Motion Picture Arts and Sciences (AMPAS) Tone mapping operator.
If you are taking jpegs or PNGs out of there then this will take the raw frame buffer and make it look more like what a digital or film camera would do do the scene data.
If you are planning on taking your images to photoshop or lightroom, then simply save the EXR and Adobe will apply their own TMO to it when you head into camera raw.
Just flip type between Hable and Ampas. This partially corrects a whole bunch of light and color artifacts - so now need to act like it’s 2008 and use highlight burn.
Here is John Hable’s tone mapper - this was designed for videogames and was made for Uncharted on PS3.
It has a bit of configuration available
The Acededmy’s ACES (AMPAS) tonemapper - which is pretty ubiquituous in Hollywood and video production now
for the OCIO profiles - load in the OCIO here (You don’t need the filmic tonemapper layer for this)
Troy Sobotka’s AGX
by default this will give a film-like quality to images, soft contrast and natural highlights.
The Kronos Neutral PBR tonemapper has been design to maintain colour over all else. Useful if you are working with products(perhaps less so interiors)
ToneMapping/PBR_Neutral at main · KhronosGroup/ToneMapping · GitHub
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Thank you so much!!!
It’s more granular than what I need at the moment - Just doing booth renderings for tradeshows so constant client changes and quick but as realistic as possible indoors renderings (quality only medium to Medium+).
But I will definetely explore these options more in depth asap and hopefully improve my renderings - thank you again!!!
Your are welcome.
This is a professional area of passion for me - I’ve just added a few more details - you might want to look at the Khronos PBR neutral option - this will get rid of highlight blowout and it will keep your trade show colours closer to the samples you are given
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Thank you so much!!!
Love it. Learned something new. Which is why I like rendering and V-Ray in particular - always more to learn!
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I tend to go straight to AGX as it solves a lot of issues to begin with
The color science stuff is fascinating
Here is a great example of why you need to make these changes if you aren’t taking the exrs to photoshop
Small setup 3 pure primary lights with basic spotlights straight from the framebuffer - not intended for use as is really.
Notice some weird stuff - the lights are more colorful in the middle where they are actually brighter.
There are rings of saturation and brightness , when actually the lights themselves do not have the properties to cause this.
This is all caused by how the basic math that combines the R G and B channels doesn’t match our eyes perceive color and values of color and intensity beyond what our screen can show are thrown or clipped away.
now if we flip on the filmic tonemapper - ampas in this case >
Look at immediately how the sphere now looks softer and rounder, those weird shifts in saturation such as the yellow are gone.
0 render time to do this, it’s purely an improvement in processing the image.
now we can actually go further and use something more modern and better thought through
Now I’ve turned on AGX via OCIO.
Look at how much more perceptually naturally the colors are now being mixed - we’ve actually got more detail in our lights that we didn’t know we had.
That actually looks more real. no changes to materials, lighting or anything, simply better image formation that helps create an image that looks closer to how we see things in real life.
The other 2 examples literally look broken by comparison - most people use the most broken look by default!
Fascinating! I love it! While my process is sometimes more rooted in appeal, less in realism (these models need to be made very quickly and make the booth very attaractive, not necessarly trully accurate), I will definetely dig into this and explore the options you mentioned as soon as my schedule permits. I look forward to it! Again, thank you Adam for your passion and thorough explanations and comments!
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