Pushing Film - In the Scan Or in the Grade

[Jacob Zalutsky]

I recently shot a project where I exposed for a 1 stop push that I had planned to have happen when we scan the film.

I believe we had a miscommunication with the scanning house as it appears they didn't raise the exposure. That said this led me to a broader question - does it matter if you push the exposure in the scan or in the grade? Also, When scanning film to a flat Log workflow where should middle grey sit?

Edited December 19, 2015 by Jacob Zalutsky

[Adrian Sierkowski]

You would in reality push in the processing. That's what push processing really is.

 

As for your grade, it depends on what format you scanned into as to how much difference it would make. It would be better to do it in the scan, but 1 stop really isn't all that much.

[Tyler Purcell]

Yep, if you need to push, you'd do that in the photochemical process, not the digitizing process.

[Jacob Zalutsky]

sure I understand what "pushing" really means - Scan was Pro Res 4444 2K.

 

I am looking to know if there is any real difference in what is happening technically in the scan that would lead to a better result then in the grade or if there is not much difference. Especially from someone in that industry.

 

thanks.

Edited December 19, 2015 by Jacob Zalutsky

[Bill DiPietra]

I think I am looking to know if there is any real difference in what is happening technically in the scan that would lead to a better result.

 

...you mean as opposed to the photo-chemical push-process?...

[David Mullen ASC]

I thought there was some sort of standard for a scan in terms of brightness levels.

[Robert Houllahan]

I have made "standard" scan illumination profiles for various stocks, that said if the negative is very dense or very thin the scanner light levels will need adjustment. The idea of a data scan is to capture the full range of the films density without clipping and without adding any noise. Scanners generally achieve this more (a true RGB slow scanner) or less ( a fast cmos based machine ) and with a full representation of the film density the brightness should be achieved in the grade.

[Jacob Zalutsky]

Thank you for this info Robert - guessing the result of a scan that didn't properly adjust for a thin negative be increased noise when you do a color grade and lift the picture?

 

On the digital side I have become familiar with shooting LOG on the Alexa and other cameras and Middle grey might be around 40-45IRE - I'm wondering when you work with a scanner if you would be trying to achieve similar results with adjustments?

[David Mullen ASC]

I've just never heard of asking for a "1-stop push" from a scanner. Generally a scan goes to uncompressed DPX files and doing a 1-stop boost in color-correction from those isn't really going to increase the noise so much as it would make the grain in the shadows more pronounced.

[Robert Houllahan]

"Thank you for this info Robert - guessing the result of a scan that didn't properly adjust for a thin negative be increased noise when you do a color grade and lift the picture?"

 

This really depends, remember that the negative puts the shadows generally in the brightest part of the sensors DR so as long as the scanners sensor is low noise the digital grade wont really produce any more noise than printing up negative in a film to film workflow it will just increase the appearance of the inherent grain in the shadows of the negative. What is more common on the newer faster scanners with cmos sensors is getting sensor noise in the hilites of more dense negative.

[David Mullen ASC]

Yes, that's good to remember, that a thin negative actually causes more light to hit the sensor of the scanner.

[Perry Paolantonio]

The point of a scan is to get as faithful a reproduction of the film in digital form as is possible. So when you do a flat scan, most scanners will allow you to tweak lift, gamma and gain, but we only use those to ensure that nothing is crushed or clipped. That allows the colorist maximum flexibility later on, in tools that are meant to do that kind of work, on monitors that are properly calibrated.

 

 

While we could boost an underexposed neg during the scan, I generally wouldn't.'

 

And yeah - dense neg is where scanners start to have trouble, because you're essentially looking at a low-light situation for the sensor in the scanner, and that means more noise in the picture -- you're pushing the dynamic range of the sensor to its limits in those extremes.

[Robert Houllahan]

And yeah - dense neg is where scanners start to have trouble, because you're essentially looking at a low-light situation for the sensor in the scanner, and that means more noise in the picture -- you're pushing the dynamic range of the sensor to its limits in those extremes.

 

 

Well that is on CMOS machines, scanners with large pixel CCDs running 1-Tap or some Tri-Linear sensors won't introduce their own noise in this situation, those machines tens to be slow though.