When you should color grade in log vs. linear | DaVinci Resolve

Grading in linear is a key piece in getting better grades - but knowing when to grade in log instead will take your results even further. Let's take a deep dive what linear and log spaces how, and what tools work best in each.
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[@pdou6796]

Again, Cullen, fabulous job with this explanation. Thank you. The point about using the HDR tool for linear exposure adjustment helped me greatly. The other takeaway for me was your point about not chasing adjustments back and forth. Both tips helped me understand the source of some frustrations here at the very start of my journey to improve my color work.

[@Mionwang]

Would you ever consider a series where you critique your audience's grades? That's something I personally feel would help me immensely. Perhaps in a grade school session?

[@Squatrecords]

Agree! Critique videos are awesome learning tool

[@Reuel_Media]

Colour grading is very subjective so I don’t know how useful critiques would be hahah

[@biswajit07]

​@@Reuel_Mediayeah, i mean if, for instance, i grade a clip to make it look like the joker 2, you guys can definitely see in the trailer how the skin tones are way off (that's the look they went for), and if i give my clip to someone to critique, that's the first thing they will point out, lol. I think, in color grading, your client is your best critique. If they like it, then to hell with anyone else😂

[@Sanatas66623]

With briefing and intention of the grade would be great.

[@Squatrecords]

@@Reuel_Media you can know when the grading is a bad grading, and knowing why is useful

[@mcneilbelle]

Yea i definitely need to see more linear vs log videos I find it so fascinating and I would love to have an even better understanding on when and where to use both of them

[@swolodkin]

Cullen, please help me understand this video. You first said that more looky-feely adjustments are better done in a Log space and I get that. Next you said that Exposure and Balance adjustments are better done in a Linear space; however, your default node graph that we've always used has Exposure and Balance being adjusted in DaVinci Wide Gamut / Intermediate - a Log space. You went on to say that using the HDR wheels you can adjust exposure Linearly using photometric stops; however, photometric stops are exponential, not linear - but we perceive them as linear. Please explain how I've gotten this wrong. Thanks and thank you for being my mentor in all things color!

[@tombojumbo]

in his default node graph he right clicks the exposure node and sets it to linear.

[@swolodkin]

In his newest all-node color management paradigm, in the Prim node (exposure & contrast) he does not set it to Linear, he sets the composite mode to Luminosity; however, he does set the Balance node to Linear. I don't recall him in the past setting the Exposure node to Linear, but I could be wrong. In any case, the newest default node graph does not have the exposure as Linear.

[@breveganlyfe]

@@swolodkin I am as confused as you on the same matter lol

[@swolodkin]

After further research, I've concluded that your Prim or Exposure/Contrast node should be in Linear. But as with all these settings, they can be subject to change and should be used in accordance with your specific application.

[@jhonastete]

I was using linear gain instead of offset as you said is better in one of your videos from last year. Now I now why

[@cinema8564]

Been waiting for this powerful option to be discussed! So helpful in for than a few circumstances. Thanks!

[@jannasc]

I was in need to this video! Now I really understook the linear vs log concepts and applications!

[@bigsnap5]

I've been waiting for this topic. Please expand on this in the future.

[@alexander_mejia]

Incredible information. Thank you for this knowledge.

[@maybepranav]

You dropped this at the perfect time haha. I just finished the first pass of a grade where I was using HDR wheels for Balance adjustments instead of Primaries just because I thought it might give me a better rendition because of it being color space aware. Thank you for explaining in such great detail about this!

[@equisetuminc]

first, thank you for reintroducing the grading dctl - I use it all the time. this is a subtly excellent explanation of something that has been puzzling me forever (log v linear). Many thanks.

[@MarcelGieseColorist]

Thanks a lot for your work 🙏

[@CineAmaniacs]

Ive been waiting on this video for a long time thanks so much cullen if you ever get some time id love to see a video on look dev using Arri log3 with the mid grey dctl

[@Squatrecords]

You are amazing! Thank you so much for this!

[@taylor4379]

Very helpful. I'd like to see a technical breakdown of where and how damage is done when using Slog-3 in 8-bit. Also a comparison between Slog2/Slog3/HLG/709/etc. Maybe trade-offs, use-cases, etc.

[@Hikebike365]

Great ! Thanks Cullen

[@EzraaaDave]

Hey Cullen, can you please drop a download link for the DWG gray. Thank you

[@CullenKelly]

Hey there! Try this link: procolor.ist/starter-kit/

[@jerwared]

Thanks for your expertise, each time a great pleasure :))))

[@valentinmanyanin9871]

Would love to see an iphone footage related video, best luts/transforms for log shooting an espicially for regular hdr footage, i feel like many people struggle to get it right

[@JeiShian]

You're the best! Thank you!

[@krischanrudolph6005]

Thanks for the Video. What about the link to the Gray patch DCTL ?

[@equisetuminc]

I downloaded it from an older video (maybe mid-2023?)

[@shebbe]

Nicely put together. I think we should be a bit careful with saying that log is for look developement. It’s really only the tools you use that determine the preferred color space/model. Any tool could be part of lookdev. And when the tool is color managed, the incoming data isn't even relevant, although in the case of Resolve this is slightly questionable... Regarding log vs linear exposure, it would’ve been cool to highlight the reason shadows ‘milk’, because of the black toe in the curve. Most colorists actually prefer this behavior (out of habit probably). But I’m not one of them :)

[@jamied6166]

I think some of this is misleading... At around 8:45 you say you're getting a faster response from the offset in the shadows than in the midtones and highlights. In log that isn't really true for offset, the midtones are affected more than the shadows or highlights. Hence why printer lights are nice to use in log. You're comparing the offset (an add operation) to linear gain (a multiply operation). The effect of offset will add to the whole tonal range but actually less in the shadows when in log than when in straight unmanaged 709 for example. First time I've ever felt I disagree with anything you've said, your tutorials are superb and your eloquent delivery is always excellent! Thanks for the sharing the knowledge!

[@CullenKelly]

Thanks for weighing in here! The confusion is that you're comparing the response of the offset wheel in log to the response of the offset wheel in a gamma space -- in this comparison, you're 100% right that shadows will be less affected while in log. My comparison, however, is log offset vs linear gain, which I made to demonstrate that even though offset is generally considered to be an "exposure" adjustment, it has too fast a response in the low end compared to a true exposure adjustment (linear gain). Hope this helps -- happy to discuss further in Grade School!

[@jamied6166]

@@CullenKelly Cool, thanks for the reply! I guess we're in agreement then, just a little confusion with what's comparing and the terms.

[@spartanstanley]

I’ve been doing this wrong since…always. Great video! Thanks!

[@Longdancer]

Hi Cullen Are you going to upload the panel discussion you hosted yesterday about exposure? I only managed to see half the event as i had family commitments. Thanks again for all the hard work.

[@Lathrop_Media]

would you ever map the HDR wheels, to say clog3 for example, and adjust exposure prior to a DWG CST? I'm finding that this works pretty well when ETTR, setting basic exposure pre CST, with color adjustments in DWG/Davinici Intermediate, and then some final contrast/level adjustments after the final CST to rec 709.

[@koushikbhattacharya832]

thank u sir♥

[@christian-schubert]

Hey, since you're one of the leading grading experts that really seem to know what they're doing - how do you tackle the classic orange-teal look? The textbook way of doing this seems to be raising the reds and tone down the blues and greens on the high end, while basically doing the opposite on the low end spectrum of the curves. However, this of course desaturates a nice blue sky, giving it a dull, uninspiringly washed out look (in cases where the sky IS the brightest part of the overall image). Would be really interesting to hear your thoughts on this! Cheers ✌️

[@nitromusik9275]

6:27 Burning question about the wheels. Is there a way to change sensibility of the wheels? You changed the image significantly yet the wheels look almost untouched. This finiky behavior drives me nuts when im grading, there is no fine tuning possible when 1mm movement of the dot is already a change like day and night.

[@stefanocson6237]

great

[@SamudithaDilshan99]

can you tell me deference between public beta version and other.

[@suhaib2789]

Would you rather manage sat in log or linear?

[@mikedobbs1575]

Wheres the davinci grey image link?

[@joellohsen]

Where can I find the DWG grey patch at? Is it available for download?

[@imteee]

I think he forgot to put the link under the description tab, you can google "procolor .ist Color Grading & Look Design Kit" instead

[@daviddesgardin]

Thanks Cullen! One precision though, if you’re working in a wider color space (DWG for ex), to have a more accurate result you need to tag the gamma and the gamut of the camera, on the HDR palette. If not, Resolve will interpret the shot as a DWG colorspace, so the final result won’t be as realistic as it could be.

[@grahamf695]

Doesn't Resolve Color Management do that automatically as part of the clip transform from say Canon Log or Rec.709 into the DWG?

[@CullenKelly]

Hey! There’s no need to set those tags in the HDR palette - if you’ve selected the right Timeline Color Space in your project settings, all will be handled automatically 👍🏻

[@daviddesgardin]

@@CullenKelly Thank you for your answer! But you can choose only one timeline color space, right? So your HDR palette is linked to this specific colorspace, what if you want to link it to the color space of the image you’re grading? Maybe I’m missing something… Anyway, thanks again :)

[@obe3]

​​@@daviddesgardin If you have an IDT that takes you from your camera space to working space (for E.G. DWG) then you do an HDR tool operation in that working space of DWG, the HDR tool will reference the timeline working space in settings which is listed as DWG. So at the time of the operation it is actually in DWG due to the IDT and by referencing the timeline settings it knows to operate in that space. Essentially what ever unified working space you convert to, you would list that as your timeline working space in settings. But you must convert to and work in that space.

[@daviddesgardin]

@@obe3 My point is that the DWG has a different range of colors (usually wider) than the other color spaces. So when you are converting a color space to another, for ex slog3/sgamut3cine to DWG, then you operate in DWG, so the maths will be different than in the original color space of the camera. If your timeline is set to DWG, your HDR palette will be as well by default. So if you increase for ex the exposure, the result will be good, but not accurate. It will end up with a small gamma shift, to have the exact same result that you would have in the raw tab, you need to operate in the same color space than your camera. Unless I missed something, or maybe I misunderstood what you said?

[@kentjensen4504]

So, I presume you don't have some kind of course people could purchase, because if yo did you strike me as someone wth the wherewithall to make a link to such a course easily discoverable. You're amazing, so I'm sad there is no such course.

[@antonarap]

By linear you mean YRGB like control response? Playing around with a gradient doesn't seem to verify what you're saying. Offset in da Vinci WG mostly affects midtones, it's like a gamma adjustment. When I set"linear" in-node, it's the same, just less pronounced. Offset is offset only in YRGB.

[@grahamf695]

Fascinating video, thanks Cullen . Please could you confirm my understanding on a couple of things. I think you are saying that Rec. 709 is a linear space, whereas DWG is a log space. In a DWG time line, Primaries - Color Wheels adjust in a log manner akin to the behaviour of the human eye - whereas the HDR Color Wheels adjust in a linear manner akin to a photometric adjustment such as exposure. Is that correct? There is a third set of wheels that you did not mention; the Primaries - Log Wheels. How do they behave in this context? Thanks.

[@GabrielAlves-lp1qr]

Rec.709 is not linear.

[@grahamf695]

@@GabrielAlves-lp1qr thanks for clarifying. What is the difference between log and Rec.709?

[@Blvck.Impala]

❤

[@brmoogma]

What about the temp tool? Does it work in linear?

[@CullenKelly]

Temp tool in the primaries? My 2c is it doesn't work in log *or* linear 😂

[@user-ok8xx8wf2c]

10:35 Does it mean Gain Wheel in Linear domain works exactly the same as HDR-Global Wheel in Log?

[@CullenKelly]

Great question! Yes, they should work the same, unless you move the black offset.

[@user-ok8xx8wf2c]

@@CullenKelly Interesting! For me it works the other way. When i set the Timeline Color Space to LOG, Global Wheel works as an Offset Wheel in Linear domain, but with some kind of "preserved" blacks. When i set Timelene Color Space to Rec709 or Linear, the Global Wheel works as Gain Wheel in Linear domain. DaVinci Resolve 19 Beta4, Davinci YRGB.

[@castielvargastv7931]

I never use the hdr wheels because i dont know for what. No i get an idea.

[@kentjensen4504]

I've asked two or three times if you have a course,a nd I have yet to receive any kind of reaction.

[@CullenKelly]

Hey! Apologies if I missed it! If you download any one of my freebies, you'll be added to our newsletter. All of the information on upcoming courses is distributed through the newsletter!

[@BANGBONSCHANNEL]

❤