mismatch between vfb and photoshop

[super gnu]

preface: any time anyone starts explaining colour management to me i glaze over and get a headache.. bear that in mind.

ive got a windows 10 workstation with an uncalibrated monitor... its quite a good one and ive never had issues with clients and colour.. windows colour settings at default.

ive got photoshop set to adobe98, set this way on advice of retoucher friend i sometimes work with.

ive got 3dsmax and vray6 set to the default colour settings. gamma 2.2 in max.


ive eyeballed a 3d scene that has to match a photographic image... i did this by opening photoshop with the reference image in, and the ipr vfb side-by-side.. the sky/horizon in the 3d scene is camera mapped projection of the reference photo, loaded with vraybitmap. the rest is 3d stuff

ive now got a great match.

save out the render as jpeg, open in photoshop, foreground greyish gravel now has a pinky/yellow tint, not shown in vfb

save out an exr, open in photoshop, gravel matches much closer, but now sky (taken from reference image originally) has a pinkish tint to it.


given im basically "mr default settings" what on earth do i do to get a 100% match between the vfb and Photoshop? ideally a simple step-by-step rather than trying to get me to understand colour theory, possibly a futile endeavour.

on a related note, would adopting the "acesCG" workflow resolve these issues? ive been meaning to set that up for months, having seen the results, but understanding what "it" is rather less than i should. but im either crazy busy on a job or sick of looking at my pc..

[vladimir_krastev]

Hi, thanks for posting. Could you attach a few screengrabs so we can better understand what is your issue?

[s_gru]

hi. ok. here's what you want. in photoshop go to Edit menu > Color Settings and adjust your settings to be like the screen shot attached.

you are going to want to have your monitor set to sRGB (ideally you'd calibrate & profile the monitor but you probably don't have to now). you'll want PS to work in sRGB by default. any mis-matches will be announced (with the settings attached) and you will be able to decide what to do.

in Vray frame buffer, choose sRGB as shown in the 2nd attachment.

if i'm set to sRGB my renders are typically pretty darn close in the VFB and in Photoshop... and in Photoshop when I open the render it will tell me "there's no profile (or colorspace) embedded, what do you want to do?" then i select the option to "assign working color space" (which according to the settings i've changed is sRGB).

now, this is basically an sRGB workflow setup for Photoshop & for Vray.

the tricky part is this: you get a background image from someone that has a different color profile than sRGB (this could happen because the image was taken with a cellphone like apple, or a nikon camera or canon camera and that photographer used aRGB profile and forgot to convert it to sRGB for you to work with.

with your current photoshop settings (aRGB) you might open the image and it'd look fairly good... it won't be oversaturated colors (reds too red etc) but lets say you load that into Vray and Max, it would probably show a lot differently.

so what you could do, is change the settings in PS like i show, then when you open up a photo that's in aRGB, it'll ask you what do you want? you could leave it as is, not assign/change or convert, but just make sure that after you ( work your magic in PS, convert to sRGB then save it as a .jpg or .png or whatever and mkae sure "embed profile" is enabled in the save as dialog box. (i've got that screen shot attached too - it's under the edit menu in PS.

now you'll have sRGB images to put into Vray.

sRGB is pretty much the most common, and, if you ever save an image from the internet or other cellphones/cameras and you open it in Photoshop, you can say "leave it as is" or "assign sRGB" and it'll pretty much look like it's supposed to.

when you open a render from Vray, it'll ask what you want to do. in this case, you'd assign sRGB to it.

**the thing is with different color profiles, the RGB numbers mean different colors when compared to each other. if you picked a red color in sRGB that is R:200 G: 80 B:59, aRGB would show you a different color! it still might be red but it might be way darker or way brighter red than what you want. a digital camera may take pictures and embed a different color profile altogether, P3 for example. well, if you open that in photoshop and photoshop is smart enough to recognize that, then in the end, you'd want to convert that P3 into the common sRGB before sharing it.

**the reason people might want a different profile is that these profiles can give a bigger gamut when compared to another profile. practically, that means if you have a nice smooth dark blue to light blue gradient sky, you can use curves or levels to give it more contrast, color, or brightness. a smaller gamut will tend to show bands of blue which sucks. a larger gamut would let you "push" the levels or curves (brightness/contrast or color) to get brighter or more contrast without getting the distinct bands. sRGB has a small color gamut compared to aRGB or Prophoto or apparently with ACEScg (which is in Vray but noone understands how to use it in a practical/real world way - i've been struggling with understanding it. at some point i will, then i'll write a definitive guide on how to use it b/c there are many benefits to larger color gamuts. sorry for the digression. a larger gamut means more colors to work with practically speaking. bit-depth means the same. 8-bit vs 16-bit for example. but anyway. this might solve your problem.

[vladimir_krastev]

Hi

ive got photoshop set to adobe98, set this way on advice of retoucher friend i sometimes work with.

This will lead to this

save out the render as jpeg, open in photoshop, foreground greyish gravel now has a pinky/yellow tint, not shown in vfb

save out an exr, open in photoshop, gravel matches much closer, but now sky (taken from reference image originally) has a pinkish tint to it.

Why not leave your Photoshop to sRGB when using images coming from the VFB? If you have images coming with different profiles you will need to adapt accordingly using Photoshop or other image editing software.

[super gnu]

Unfortunately im usually constrained due to the fact that whenever i work with a retoucher (quite common) they invariably have their photoshop set to adobe rgb... i have to work with their psds and/or send them something that looks right when they open it. have you ever tried asking a retoucher to change their photoshop settings?! you may as well ask them to eat a turd sandwich. an adobe98 profile for the vfb would be cool

i will await that definitive guide on acescg in the meantime.

[francomanko]

yeah, our retoucher only uses adobe profile too.

[Mr.Mxyzptlk]

hi. ok. here's what you want. in photoshop go to Edit menu > Color Settings and adjust your settings to be like the screen shot attached.

you are going to want to have your monitor set to sRGB (ideally you'd calibrate & profile the monitor but you probably don't have to now). you'll want PS to work in sRGB by default. any mis-matches will be announced (with the settings attached) and you will be able to decide what to do.

in Vray frame buffer, choose sRGB as shown in the 2nd attachment.

if i'm set to sRGB my renders are typically pretty darn close in the VFB and in Photoshop... and in Photoshop when I open the render it will tell me "there's no profile (or colorspace) embedded, what do you want to do?" then i select the option to "assign working color space" (which according to the settings i've changed is sRGB).

now, this is basically an sRGB workflow setup for Photoshop & for Vray.

the tricky part is this: you get a background image from someone that has a different color profile than sRGB (this could happen because the image was taken with a cellphone like apple, or a nikon camera or canon camera and that photographer used aRGB profile and forgot to convert it to sRGB for you to work with.

with your current photoshop settings (aRGB) you might open the image and it'd look fairly good... it won't be oversaturated colors (reds too red etc) but lets say you load that into Vray and Max, it would probably show a lot differently.

so what you could do, is change the settings in PS like i show, then when you open up a photo that's in aRGB, it'll ask you what do you want? you could leave it as is, not assign/change or convert, but just make sure that after you ( work your magic in PS, convert to sRGB then save it as a .jpg or .png or whatever and mkae sure "embed profile" is enabled in the save as dialog box. (i've got that screen shot attached too - it's under the edit menu in PS.

now you'll have sRGB images to put into Vray.

sRGB is pretty much the most common, and, if you ever save an image from the internet or other cellphones/cameras and you open it in Photoshop, you can say "leave it as is" or "assign sRGB" and it'll pretty much look like it's supposed to.

when you open a render from Vray, it'll ask what you want to do. in this case, you'd assign sRGB to it.

**the thing is with different color profiles, the RGB numbers mean different colors when compared to each other. if you picked a red color in sRGB that is R:200 G: 80 B:59, aRGB would show you a different color! it still might be red but it might be way darker or way brighter red than what you want. a digital camera may take pictures and embed a different color profile altogether, P3 for example. well, if you open that in photoshop and photoshop is smart enough to recognize that, then in the end, you'd want to convert that P3 into the common sRGB before sharing it.

**the reason people might want a different profile is that these profiles can give a bigger gamut when compared to another profile. practically, that means if you have a nice smooth dark blue to light blue gradient sky, you can use curves or levels to give it more contrast, color, or brightness. a smaller gamut will tend to show bands of blue which sucks. a larger gamut would let you "push" the levels or curves (brightness/contrast or color) to get brighter or more contrast without getting the distinct bands. sRGB has a small color gamut compared to aRGB or Prophoto or apparently with ACEScg (which is in Vray but noone understands how to use it in a practical/real world way - i've been struggling with understanding it. at some point i will, then i'll write a definitive guide on how to use it b/c there are many benefits to larger color gamuts. sorry for the digression. a larger gamut means more colors to work with practically speaking. bit-depth means the same. 8-bit vs 16-bit for example. but anyway. this might solve your problem.

It's silly how convoluted this process is all these years later.

[francomanko]

is it possible to use a LUT in the vfb to mimic the adobe colorspace?

[s_gru]

is it possible to use a LUT in the vfb to mimic the adobe colorspace?

so now, in 3ds max 2024 you can set a color management to acescg with one-click. then you can select the output color space and they include aRGB! the downside to that is that you have to make sure you tell vray you want your bitmaps to be thought of as sRGB and it'll convert it to acescg for you when you render! there's a few other little things but it's a lot easier and i've tested it out. all my bitmaps are sRGB or untagged (to me untagged usually means sRGB). and i don't use any naming or anything like that for auto-detection, i just manually switch input color to srgb for the bitmap when i create it. you also have to use vray color map and set it to acescg and use that in the diffuse slot if youre just doing a simple color, or picking a color from a website like sherwin williams.

as far as being convoluted, it is convoluted, but then so is color management ha! think of this, for any photoshop work (photography, press graphics etc) you have to have good color management in order to reproduce the colors you see on-screen on a print. i remember the first day i bought a nice dye-sublimation printer to make little 4x6 prints of photos i took with my new digital camera. my nephew chased his dog around and had a bright red polo shirt on. on printing, i got big red splotches on his red shirt and some of the splotches were pink! that'[s when i started learning about color management. once photoshop is set up, your monitor calibrated & profiled (re-do profile every 6 months at least) you're more or less good to go in any situation. note also, that i have profiled the paper i print on! do this by printing 80 or many more pre-determined color squares on your paper, then scan each color so photoshop know what numbers to use for "that green" or "that skin tone" etc... when it goes from the actual image to the printer. the saving grace is that in most situations sRGB is assumed to be the "consumer" color space. so printers, monitors and digital cameras come with the capability to handle sRGB.

even with all of the above (color management) there's still times when my print won't exactly match what i see on my screen and in a lot of cases i can barely even notice it if at all. but there are people out there that will photograph a priceless piece of art/painting and they have to follow an arduous task of recreating the digital file that looks accurate on the monitor AND when they print it on certain paper and certain inkset on certain printers (in fact specific ink and specific printers because each one is always a little different. they will charge thousands of dollars and it will take weeks or months to get it right. then the museum has an exact copy in print for and digital form, for travelling shows or public display when the real one should be carefully stored away from color fading daylight or other lighting.

[s_gru]

i was gonna add that in my line of work, architectural, a great practical example is when we get photos from professional photographers. they will provide us with a wider gamut profile embedded in the images, say P3 or aRGB. then we put them up on our website. then the management team comes and complains that the photos are WAY oversaturated and look horrible, alien planet like. that's when i ask the marketing team to give me the photos and i convert them to sRGB, we re-post and everyone is happy.