Better colors - better LUTs?

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Johan Cramer

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Better colors - better LUTs?

PostTue Dec 31, 2013 11:46 am

Getting natural-looking color out of BMD cameras is - IMHO - still a challenge. When shooting with "film" dynamic (whether in ProRes or Raw) and applying either Blackmagic's Cinema Camera Film to Rec709 LUT or Captain Hook's LUT, the result still doesn't look natural: cold colors/blues (including skies) have a green tint and become turquoise, warm colors tend to go brown.

Do people know better LUTs, Powergrades or other color correction tricks to get pleasant, non-artificial looking colors out of BMD footage?
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E Lawes

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Re: Better colors - better LUTs?

PostTue Dec 31, 2013 1:58 pm

Try using this Technicolor three strip node structure as way of getting from the film LUT to something more natural looking as a base for grading. It's contentious as an emulation of the three strip process but I find it works well as a sort of LUT structure to start with (also bear in mind that with most LUTs you should grade underneath them first, then add some adjustments at the end if necessary. Don't just apply one in your first node and expect it will work for any shot).

http://www.mynahmedia.com/2013/01/3-str ... i-resolve/
http://www.1-4-4.com/
https://vimeo.com/production144
@1l4l4
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Oscar Romero

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Re: Better colors - better LUTs?

PostTue Dec 31, 2013 2:51 pm

E Lawes wrote:Try using this Technicolor three strip node structure as way of getting from the film LUT to something more natural looking as a base for grading. It's contentious as an emulation of the three strip process but I find it works well as a sort of LUT structure to start with (also bear in mind that with most LUTs you should grade underneath them first, then add some adjustments at the end if necessary. Don't just apply one in your first node and expect it will work for any shot).

http://www.mynahmedia.com/2013/01/3-str ... i-resolve/



Yes! That's the work flow. The LUT is always at the end of the grading tree and all correction should be done before it.
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Johan Cramer

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Re: Better colors - better LUTs?

PostTue Dec 31, 2013 3:26 pm

I was actually aware that the LUT should be applied last. The problem only seems to me that the two widely available LUTs for transforming Blackmagic film log footage to Rec709 produce rather artificially looking colors with brown/turquoise casts. This can also be seen on most footage shot on BMD cameras on Vimeo and elsewhere.

Clearly, this can be overcome with tweaking colors in Resolve before applying the LUT. But I only wondered whether better LUTs - or Resolve Powergrades - for a more natural color reproduction (i.e. higher color fidelity/accuracy transformation from BMD Film Log to Rec.709) are available.

Or is there a deeper underlying problem (as suggested here:
), namely that chroma resolution in BMD cameras is comparatively weak? I can't believe that, since great dynamic range should also translate into great color depth.
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adamroberts

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Re: Better colors - better LUTs?

PostTue Dec 31, 2013 5:10 pm

You don't need to apply a LUT. Applying a LUT is not grading. Most LUTs are there to translate footage from one clout space to another or as a starting point in the creative process.

If you learn to use the tools in Resolve you can do everything the LUT does and more. The LUTs after all can be created in Resolve. If I'm not mistaken Captain Hooks LUT was creating inside resolve.

Start with the LOG colour wheels. Balance the colour and exposure. Then adjust the Lift (shadows), Gamma (mids) & Gain (highlights) to get the contrast into your image. You can also adjust the colour balance in each.

You can the use the qualifiers to target specific colour ranges.

If there is a set of corrections you make to every clip you can use that to create a LUT and you can apply the LUT as your starting point each time (that is what Captain Hooks LUT is intended to be).
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Johan Cramer

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Re: Better colors - better LUTs?

PostTue Dec 31, 2013 6:54 pm

Maybe I'm not clear enough in what I'm trying to say, but I am fully aware that LUTs are not grading, and that their purpose is to transform footage from one color space to another. (That's exactly what I wrote above btw.)

The problem is that, with the standard Blackmagic Film Gamma to Rec709 LUT and with the (alternative) Captain Hook LUT, translation from Blackmagic Film log footage to Rec709 results in weird colors.

Of course that can be fixed by color correction in Resolve, but rather than making up for the deficiencies LUTs that are not fully doing what they're supposed to do (namely a clean translation from one colorspace to another, resulting in correct colors as opposed to - among others - turquoise skies), I wonder whether better LUTs, or ready-made PowerGrades exist that we can share without everyone of us having to rebuild fixes from scratch.
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Will Tejeda

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Re: Better colors - better LUTs?

PostWed Jan 01, 2014 8:19 am

I think the bigger issue here is making sure people are shooting the right way..


The black magic cinema can is notorious for its it pollution when using nd filters, thus giving brown footage.
It was the first thing I noticed when I started shooting with the camera.

Also due to there being limited white balance options in-camera, you have to make sure you WB in resolve first (if shooting raw) or WB with curves in your editor...


All this need to be done before even thinking of what LUT you'll be using .

This is where most of those vid on YouTube /video that you've been watching are probably messing up. I've seen it.

Hell, I've done it myself when first getting the cam.


I've used hooks out and have had perfect results once the above has been done.
Will Tejeda
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Art Roberts

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 12:08 am

Paragram, I do understand why you are puzzled by the green color cast when shooting with the BMCC. I was too, until I came to terms with the fact that the BMCC is a FILM camera. I'm placing more emphasis on "FILM", because their gamma is quite different from other cameras, an example being the BMD production camera.
This is a quote from Apple's website " A color cast is an unwanted tint in the image due to the lighting, the white balance of the video camera, or the type of film stock used given the lighting conditions during the shoot."
I don't want to get into some technical jargon, but generally, a film camera will primarily generate a green cast . It's what makes film look like film, as far as separating the men from the boys, if you get my drift. Take more trips to the movie theater
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Occular

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 2:00 am

Hi pacman829, thanks for mentioning the IR "brown" issue. Just found this very handy page about it at nofiomschool:

http://nofilmschool.com/2012/12/choosin ... -infrared/
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CaptainHook

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 7:54 am

My LUT is not supposed to be 'neutral' or "correct" colour wise - or a "clean translation" . I tried to be clear about that when sharing it. It's a reflection of SOME of my preferences at the time, that seemed to translate pretty well across most footage i shot - assuming i did a little work prior to the LUT (node). The idea was it saved me time from doing a lot of the same stuff.

I DID make some alternative ones though. :P

This one i don't really use and never planned to share, but it's maybe my most 'neutral' attempt (far from a technical LUT though - there's still just preference there). Like all others, you want to "prep" the image going into it, from memory this is reasonably low on contrast and can generally benefit from added density:

http://www.captainhook.co.nz/LUT_Hook/H ... utral.cube

The next ones i've been planning to share for months, but haven't gotten around to it as i want to prepare examples etc but its all very time consuming:

This is based on a LUT i made to help make matching Alexa footage (with the Alexa LUT applied) easier, this isn't THAT LUT, but built around it with more of my preferences. So it's not trying to get closer to Alexa like the other one i'll eventually release, but it's based on some of the stuff i did in that one - definitely more neutral than my first one, but still with a little 'vibe':

http://www.captainhook.co.nz/LUT_Hook/H ... _X_V1.cube

And finally, this one is maybe 6 months+ old, but it's just a minor update to my original LUT that modified some things i found myself doing with that LUT. I think it assumes a different exposure too (been way too long since i used my first one), so it won't replace instances of the old one:

http://www.captainhook.co.nz/LUT_Hook/H ... _V1.1.cube

There's another couple i plan to share with these, but that should give some 'options' at least if you like using LUTs to help get you STARTED with a grade, or for live monitoring while shooting etc.

If anyone finds them useful, let me know. And as before, you can always hit the donate button that's in my link below.
**Any post by me prior to Aug 2014 was before i started working for Blackmagic**
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CaptainHook

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 7:56 am

Occular wrote:Hi pacman829, thanks for mentioning the IR "brown" issue. Just found this very handy page about it at nofiomschool:

http://nofilmschool.com/2012/12/choosin ... -infrared/


PLEASE check the Hoya thread on BMCuser.com.
I know its against the policy here, but i have to share my findings that i posted there relating to the BMD cameras and the Tiffen filters as shown in the Abelcine video:

http://www.bmcuser.com/showthread.php?6 ... #post97497
**Any post by me prior to Aug 2014 was before i started working for Blackmagic**
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adamroberts

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 8:21 am

Thanks for sharing these addition LUTs CaptainHook.

Will have a play over the weekend.

:-)
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Frank Glencairn

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 9:59 am

IF you just looking for a more neutral point to start, I found the Alexa LUT pretty handy for this.
http://frankglencairn.wordpress.com/

I told you so :-)
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Oscar Romero

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 4:28 pm

Frank Glencairn wrote:IF you just looking for a more neutral point to start, I found the Alexa LUT pretty handy for this.


I agree. Is very neutral to start developing your look.
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otaku-house

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 5:20 pm

Cheers Capt Hook. Much appreciated.

Now in my second week of owning the pocket am starting to grade each shot from RAW happily (just boosting the saturation helps properly exposed footage get really close to neutral if you ask me), but found your first LUT terrific and something I may use from time to time when shooting ProRes. It looks especially fantastic doing night photography on NYC streets where sodium lights bump up against a lot of LED / fluouresence/ neon.

If you could shift your original LUT to more red and blue than orange and turquoise I think you'd have a fairly neutral one with some better contrast. Did you make these in Resolve?

A donation will be winding its way to you soon...
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CaptainHook

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 6:12 pm

Frank Glencairn wrote:IF you just looking for a more neutral point to start, I found the Alexa LUT pretty handy for this.

Just be aware it's designed to adjust Alexa colours - if you like the gamma curve then a better idea might be to use the Arri LUT builder to spit out a version without the colourspace conversion and just add saturation and tweak colours etc from there. Then again, if you like what the one in Resolve does to colours, why not? :)

@otaku-house - the V1.1 of my LUT pushes reds closer to where i'd like them. But ultimately i made many other LUTs/Powergrades even just 1 month after releasing it that i've used as starting points, so it's always just been an option to start from if it worked for what you're doing. It would be messy and confusing if i just put everything up that i made or experimented with. :P

It was just to help people get started back then as colour grading was new to many coming over to BMD cameras etc.
**Any post by me prior to Aug 2014 was before i started working for Blackmagic**
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adamroberts

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 6:29 pm

otaku-house wrote:Cheers Capt Hook. Much appreciated.

Now in my second week of owning the pocket am starting to grade each shot from RAW happily (just boosting the saturation helps properly exposed footage get really close to neutral if you ask me), but found your first LUT terrific and something I may use from time to time when shooting ProRes. It looks especially fantastic doing night photography on NYC streets where sodium lights bump up against a lot of LED / fluouresence/ neon.

If you could shift your original LUT to more red and blue than orange and turquoise I think you'd have a fairly neutral one with some better contrast. Did you make these in Resolve?

A donation will be winding its way to you soon...


You can make those adjustments in Resolve. Then generate a LUT. It will then incorporate the colour changes in Hook's LUT with your changes. Then you have your own unique LUT that does exactly what you want.
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John Christon

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 6:45 pm

I do think the OP has a point and this has been one of my gripes of the camera as well - the rec709 "video" LUT that is in camera is not great to say the least.

it's not terrible, but it leaves a lot to be desired. I understand that the camera may not be able to be a picture profile machine, where you can store many different looks, or adjust them on the fly, like canon dslrs can with picture profiles, but it would be nice to swap in your default "video" LUT and be able to pre-load it, or flip to that on a job, to basically shoot to edit, and not have to cc your footage.

don't get me wrong i love shooting flat to color later, but there are jobs where it's just not worth it, but I'd still love to shoot blackmagic. i don't think any of us would want to jump onto a c300 for a job where the client is afraid of shooting log footage, but likes the look of the c300 not shooting c-log. this would give us a tool to be able to dial in looks for people and not have to say, oh now you have to go through davinci, or now you have to figure out how to color this in your NLE. this has definitely turned off people from going blackmagic in jobs whereas otherwise they would have been totally sold.

if it can do the rec709 conversion, which i'm assuming is software based and not hardware based, I don't see why it couldn't do any conversion in camera, even if it's just limited to the 1 video setting. I would be so thrilled with this feature.
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otaku-house

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 8:22 pm

Capt Hook -

Oh yeah definitely. My biggest problem when i first shifted from film and printer lights to digital grades was the paralysis of too many possibilities.

Again though thanks for opening your process and sharing tools.

BTW where did you manage to get the ProND set? Has it been released yet? In US I see listings for Pro IR but not ProND.
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CaptainHook

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 8:34 pm

I got the Hoyas shipped from B&H (i'm in NZ):

http://www.bhphotovideo.com/c/search?at ... t=hoya+pro

Not the Pro 1 Digitals, but the ones named "Hoya 77mm PRO ND4X Filter" etc
**Any post by me prior to Aug 2014 was before i started working for Blackmagic**
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otaku-house

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 10:25 pm

Thank you! That's what was keeping me from turning them up.
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CaptainHook

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Re: Better colors - better LUTs?

PostThu Jan 02, 2014 10:27 pm

If you're in the US, there's package sets you can get directly for cheaper:

http://www.kenkodepot.com/products/hoya ... d-kit.html
**Any post by me prior to Aug 2014 was before i started working for Blackmagic**

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