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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

is REDLOGFLM a look or Camera RAW?

Will Keir

Will Keir

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Just doing some re-education for myself. is REDLOGFilm a color science like RC3,RG3 or is that the actually RAW look. i am guessing it's color science because i believe the sensor records in black and white naively.

Thanks for entering into a discussion for me and others to learn and wipe any misconceptions clear.

if any of your RCX guys are reading this, you guys are amazing, the unseen genius of Jim's camera system.
 
Yeah, you can't actually look at RAW footage (well, I suppose you could, but it'd just be an incredibly dark gray scale image as it would be true linear and just have sensor values with no gamma applied to them - basically it's meaningless visually.)

Every bit of Color Science is effectively an equation that is being applied to those RAW numbers to get it to a point that is viewable.

RedlogFilm is design to match a a Log workflow, where you process the footage enough that the high values and low values are stored with lots of room to raise or lower them, while being designed to be view through a LUT which changes the gamma. This will return them to something that looks more like the real world (and if it's a proper LUT being applied AFTER your corrections is calculated, will give you a very large amount of room to adjust the footage).

You don't HAVE to view this through a LUT, you could do color corrections directly from the RedLogFilm master, but your corrections would have to be more extreme to achieve a real world look (compared to viewing through a LUT and tweaking subtly, or alternatively going with say RedColor3 which may be pretty close to the look you want anyway.)

Objectively, RedLogFilm is not intended as a look. As in it's not intended to ever be the END point to display your footage, only an intermediate point to allow you to export it to other formats and retain the most flexibility in working with it and backwards compatibility with Cineon aware software (because LUTS that will work on Cineon footage to get the Log Gamma correct for your display Gamma will match up with Redlog Film.) You could use it as such if you REALLY wanted to, but effectively it's designed to create a very boring looking image that responds very well to subtle changes and looks good when used with a LUT, rather than create an extreme looking image from the get go that is harder to make subtle changes too because it's already had significant mathematical changes applied.

Basically a LUT is just a preset correcting that get's a type of footage in a known look, like RedLogFilm back to another preset based on a known viewing device. Redlog Film is based on an older known look, Cineon 10 bit Log - http://en.wikipedia.org/wiki/Cineon) which is then a good starting point to mess around with the files and has many known conversions in pieces of software, mostly compositing and grading software that previously dealt with film, to get it back to a look that looks 'natural' on your monitor.

RedColor3 and RedGamma3 in comparison bring an image more in line with regular HD footage when viewed on a screen from the get go (http://en.wikipedia.org/wiki/Rec._709) It's not a perfect match to HD TV, because Rec.709 is based around a non RGB color system and makes all sorts of assumptions about your display device and what the real world should look like on a monitor etc that really only makes is really useful for calibrating broadcast signals for live broadcast, not creative film making where more subtle looks are often the aim. Rec.709 is Really not an intermediate colorspace, it's much more of a display or target colorspace, a guideline for where your picture should end up within if it's playing on TV, not where you should start grading from to get it within that space.
 
Redlog Film is not a color science. It's a tonal distribution that conform to known Cineon 10bit specs for film workflow. Red calls it as gamma space. It's got nothing to do with color gamut in anyway. Your color science i.e. redcolor, redcolor2, redcolor3.

If you want to see the image raw without any gamma space. Activate your advanced control in redcine-x and you should see extra gamma space which call linear, that's what your sensor see (after debayering and matrixing).

Rivai
 
They are all LUTs.
 
Color science is definitely not LUT, except gamma space from red are all 1d lut

Rivai
 
Craig, that's the best most comprehensive explanation of the options that I've read/heard to date. Gives me a better idea of what I hould be doing, and what I should leave alone. I know there are different workflows for getting from camera to finished edit as far as color goes, but I'm still trying to figure that one out. But this helped me make a little more sense of it all. Thanks!
 
Craig Parkes said:
You don't HAVE to view this through a LUT, you could do color corrections directly from the RedLogFilm master, but your corrections would have to be more extreme to achieve a real world look (compared to viewing through a LUT and tweaking subtly, or alternatively going with say RedColor3 which may be pretty close to the look you want anyway.)
Click to expand...

Where do I find these LUTs? Does RCX Pro have LUTs built in, the preset curves perhaps?

So if I am using RedLogFilm as a starting point, where do I go to find the LUTs I might be looking for, or to try out? Without creating my own, or is that kind of the point? Create my own LUTs based on the projects/shoots and save them?
 
How do I activate "advanced control" in RCX?

RivaiC said:
Redlog Film is not a color science. It's a tonal distribution that conform to known Cineon 10bit specs for film workflow. Red calls it as gamma space. It's got nothing to do with color gamut in anyway. Your color science i.e. redcolor, redcolor2, redcolor3.

If you want to see the image raw without any gamma space. Activate your advanced control in redcine-x and you should see extra gamma space which call linear, that's what your sensor see (after debayering and matrixing).

Rivai
Click to expand...
 
You may find some help and insight here: http://www.lightillusion.com

Regarding Log (any version) : you can even define it as a kind of compression, since the re-distribution of values is helpful to squeeze a large DR into 12 bit instead of keeping it in huge linear 16 bit files.
It preserves very fine shades where humans perceive them at their best while discarding some information where we'd hardly notice anyway.
 
If I understand it correclty you can not see raw, raw is a black and white color pattern.. that is later going trough debayering and can then be viewed... So the big deal about RED is that however you choose to look at the r3d file the image is driven directly from the captured black and whites from the sensor. other cameras not using raw is looking down the debayering in the camera... then that process can not be rewersed later on... like looking on your old red one files with red gamma 3 debayering for example...
 
Black and white? Seriously? How about red, green and blue?
One more thing I don't get:
If redlogfilm lifts the black and compresses the highs it's compressing, so effectively cutting the dynamic range top and bottom.
how is this better?
 
OptiTek;
One more thing I don't get:
If redlogfilm lifts the black and compresses the highs it's compressing, so effectively cutting the dynamic range top and bottom.
how is this better?
Click to expand...

I hope you are beside right now and i can show why it is better. Practical approach always the best, It wont take more than 20 minutes of your time to witness it yourself. However in short, log 10bit contained 12 bit linear (some argue 16bit) worth of dynamic range. It's a very efficient way of storing data. Think of it as Cineon Log 10 bit, where you store entire film dynamic range into dpx files. You dont need higher bit depth like in linear, typically extra 12bit to 16bit(?) equivalent. But it's got nothing to do with color gamut.

The other advantages is you can easily turn it into linear light using simple log to lin function, and it makes as friendly format for VFX work. Nowadays linear light is almost mandatory in VFX workflow. After you are done with it, you can turn it back as log using lin to log and pass it to DI and start grading using Log workflow.

Hope it helps
Rivai
 
RivaiC said:
I hope you are beside right now and i can show why it is better. Practical approach always the best, It wont take more than 20 minutes of your time to witness it yourself. However in short, log 10bit contained 12 bit linear (some argue 16bit) worth of dynamic range. It's a very efficient way of storing data. Think of it as Cineon Log 10 bit, where you store entire film dynamic range into dpx files. You dont need higher bit depth like in linear, typically extra 12bit to 16bit(?) equivalent. But it's got nothing to do with color gamut.

The other advantages is you can easily turn it into linear light using simple log to lin function, and it makes as friendly format for VFX work. Nowadays linear light is almost mandatory in VFX workflow. After you are done with it, you can turn it back as log using lin to log and pass it to DI and start grading using Log workflow.

Hope it helps
Rivai
Click to expand...
Thank you for the explanation (little too convoluted for a simple question I might add) . It doesn't really answer the (simple)question:
If there are no true blacks because they are lifted the bottom of the dynamic range is not there. How is it better?
It may be the convention, it may deal better with the limitations of displays, it may even match better the response of human eyesight. another words it may be easier or more convenient-but not better range or information.....
 
Log provides for an even distribution of code values per stop of dynamic range. By putting in a black offset the math works to stop high gain near zero which can lead to excessive image noise, and gives the grade "room to move" and is necessary for the log to meet the cineon spec so that it works as grading apps expect.

The reason log encodes have more range their even distribution of code values ensures each stop has enough precision. Keeping linear light is great for colour and VFX math, but it's ever-so-wasteful on code values as each brighter stop has double the code values yet it needs no more code values than the previous darker stop. A log encode allows you to fit more stops into the available code values because it doesn't waste excessive amounts of code values on the brightest stops.

Graeme
 
Thanks Graeme (and Rivai:yesnod:)- got it!!!
Convention necessitates lifting the blacks.
 
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