log to lin

[finaldesign]

"log to lin"in the scratch what does mean? thanks

[John Tissavary]

"log to lin"in the scratch what does mean? thanks

It is an inverse log curve used to 'linearize' a log colorspace image. Most film is scanned to a log colorspace DPX file, so log to lin is quite important. Some will use a log to lin monitor LUT, but I prefer to linearize the footage, grade it, then convert it back to log space as the very last operation.

log to lin is not useful for Red footage, as Red does record in log, even Redlog is, essentially, a linear colorspace.


regards,

John T.

[Graeme Nattress]

First, gamma curves are not colour spaces!

Second RedLog is log - the curve is a log curve.
Linear means a straight line - neither video gamma nor log is linear

Linear is often abused and some people, who should know better, use it to refer to a video gamma. They are incorrect and they confuse people.

Graeme will now step down from his soapbox - normal service will be resumed presently.

I don't know what the log to lin in scratch does - perhaps Lucas would tell us precisely?

Graeme

[Colin Hubick]

I don't know what the log to lin in scratch does - perhaps Lucas would tell us precisely?

Graeme

would love to know myself...

Colin

[Lucas Wilson]

would love to know myself...

Colin

Hey guys... just a Cineon transfer curve.

In the 3D LUT section of SCRATCH, you can also adjust Soft Clip, Gamma, De-Sat., and Black/White Gamma Balance, per the Cineon spec.

Lucas

[Graeme Nattress]

Lucas, does "lin" in log to lin refer to linear light or video gamma - ie, what does it linearize to?

Graeme

[Lucas Wilson]

Lucas, does "lin" in log to lin refer to linear light or video gamma - ie, what does it linearize to?

Graeme

Hi Graeme,

I've attached a screengrab of the generic 3D LUT interface in SCRATCH, so you can see for yourself. Short answer - you can customize gamma.

Lucas

[Graeme Nattress]

So Lucas, what you're saying is that in "log to lin", the "lin" can be set to 1.0 and hence be really linear, or it can be set to 2.2 and only be linear to people who call curvy things linear?

Graeme

[Lucas Wilson]

So Lucas, what you're saying is that in "log to lin", the "lin" can be set to 1.0 and hence be really linear, or it can be set to 2.2 and only be linear to people who call curvy things linear?

Graeme

Correct. :)

There is also another setting in the "Project Settings" menu in SCRATCH that sets Neg Density, which also affects this transform.

Lucas

Lucas

[Jason Diamond]

here is a great way of looking at it:

http://prolost.blogspot.com/2005/05/log-is-new-lin.html

[finaldesign]

thanks a lot

[finaldesign]

So lucas ,what does "de-sat" mean in your screengrab of zhe generic 3D lut interface ?