Printer Lights

[neila]

Hey everyone, I'm new to this forum but I really like the discussions I'm seeing on here thus far. I'm always trying to learn so places like these are absolutely invaluable to me. So I'll start off by saying thanks!

I wanted to see if anyone had any insight on Printer Lights. I try to use them quite a bit for balancing and brightness, but I don't really know the best practice for doing so. For instance, for someone who isn't sending any renders out to a lab to be printed, I've never needed to change the default Density values. But I've seen different defaults in different programs (Resolve defaults to 1, Lustre defaults to 6.25), why is that? Is it simply a feel thing or is there a setting that makes more mathematical sense? I know they relate to f-Stop exposure levels, but the number of Steps and at what Density is equal to a 1-Stop change is fuzzy to me.

If anyone has insight on this or any other tips and tricks regarding printer lights I'd greatly appreciate it.

[Abby Bader]

Hi Neila,

Nice to see you here!

In this article by Dan Muscarella you can read that "A combination of one printer point on all the three primary colors is equal to a full 1/12 of a stop, also known as a full point of global density. " It means that if you add one point of red, one point of green and one point of green you have increased the brightness with 1/12 of a stop. If you instead add 12 point of red, 12 point of green, and 12 point of blue you have increased the brightness with 1 full stop.

Abby

Master Study in DaVinci Resolve Printer Lights - Insights - Lowepost

 

 

[neila]

Thanks Abby, that clears things up quite a bit. Just so I'm understanding it correctly, do you think that means adding 1 point to all 3 colors increases brightness by 1/12 of a stop when the density increment for each color is set to 1? Stop me if I'm overthinking this or have the wrong terminology, these kinds of things fascinate me.

Here are the default settings in Resolve and Lustre that I'm curious about:

I went down a bit of a rabbit hole researching how Baselight handles printer points. Found an interesting little tidbit in their Truelight/ACES tutorial video at the 17:50 mark. He says, "a stop in Film Grade is roughly 4.5 in ACEScc." So I guess an obvious thing I hadn't considered before was how the working space effects increasing/decreasing f-Stops.

[Abby Bader]

3 hours ago, neila said:

Just so I'm understanding it correctly, do you think that means adding 1 point to all 3 colors increases brightness by 1/12 of a stop when the density increment for each color is set to 1?

Correct. Add +1 in each color channel in the offset controls (+r +g +b) for one global density point. One global density point is 1/12 of a stop. 36 increments (+12r +12g + 12b) is a full stop. 

[Abby Bader]

Hi @neila, how are everyting going with your printer lights corrections? Please let me know if you have any further questions and I will try my best to answer.

[Thomas Singh]

I have a questions regarding printer light correction being altered through a log to linear 3D LUT. Will the LUT affect the density in a way that makes it more imprecise than if the correction was not altered through a LUT? In other words, if One global density point is 1/12 of a stop, is that still display true if the correction is altered through the LUT?

[Abby Bader]

The use of printer lights in digital processing is not an accurate science. The photomechanical process was affected by so many random parameters that we don't know how that mathematically transfers to digital data. The important thing is that you can make precise corrections in the color channel of choice, both if the correction is altered through a LUT or not. But, it certainly helps if the input data is log.

Edited January 30, 2018 by Abby Bader

[dermot.shane]

Print stock filled the role of a ouput LUT/RRT, we called printer lights while viewing a answer print,  looking at something though an effective  RRT/LUT

try looking as something through a 2383 lut, then a 2393 lut, the print stock is your lut in a lab finish

that said, i prefer subtractive color and tend to use the a & b channels of L*a*b to ballance an image

i've used printer lights for real, and see no reason to turn back to 1941 tech

Edited January 30, 2018 by dermot.shane

[Amada Daro]

Old tech but the only primary controls with full tonal range control. 

[Sam Gilling]

1 hour ago, Amada Daro said:

Old tech but the only primary controls with full tonal range control. 

I've started using the offset control in Resolve a lot for this very reason, you can move the entire signal around with one control and after a little practice can move pretty fast and do a lot with it.

Plus having only one parameter changing from shot to shot vs three with LGG means there's less to tweak on a per-shot basis as you're not pulling the signal in different directions as much. 

[dermot.shane]

10 hours ago, Amada Daro said:

Old tech but the only primary controls with full tonal range control. 

care to expand on that thought?

arn't printerlights in Resolve nothing more than a diffrent ui for Offset?

Baselight's "Exposure", Nucoda's  "Brightness", Resolve's "Offset" are all the same thing?

here's a rip from Nucoda's manual on the tool;

Density is Printer Lights ganged together and a density reset makes each of the RGB Printer Light values neutral. Density works the same as the Brightness tool in Brightness/ Contrast and is also known as offset in some other systems.

This control affects all pixels equally, regardless of luminance, color or position. Its affect is similar to camera exposure and it is useful for adjusting the source image dynamic range to a pleasing level. Since it does not squeeze or stretch the dynamic range it causes no artifacts and is a great control to start grading raw or flat scanned images.

Some use Density to set black levels and others to use it to assign the mid range. Both methods are correct.

 

i tend to use the same controls, in Resolve the Nucoda/Baselight method of normalising using Exposure/Contrast/Sat are pretty rudementary, or needing workarounds... but still vastly preferable to LGG for my working methods

the only difrence is i often mapp *a and *b rather than G and B, to the controls, the maths are the same, the color science is substaintly diffrent tho, subtractive rather than additive, but the controls remain the same, i could type in printerlights to adjust *a, or turn a knob...  same tool, diffrent ui

 

 

Edited January 31, 2018 by dermot.shane

[Amada Daro]

1 hour ago, dermot.shane said:

Baselight's "Exposure", Nucoda's  "Brightness", Resolve's "Offset" are all the same thing?

Correct, except that brightness is a single global density control (all channels ganged together) while offset also offer individual color channel control. 

1 hour ago, dermot.shane said:

11 hours ago, Amada Daro said:

Old tech but the only primary controls with full tonal range control. 

care to expand on that thought?

Lift, gamma and gain is local controls who target specific tonal ranges, while offset controls is the only tool that adjust the entire signal. 

[dermot.shane]

i get all that - but where's the advantage to the "printerlights" ui?

 

 

 

 

Edited January 31, 2018 by dermot.shane

[cameronrad]

3 hours ago, dermot.shane said:

care to expand on that thought?

arn't printerlights in Resolve nothing more than a diffrent ui for Offset?

Baselight's "Exposure", Nucoda's  "Brightness", Resolve's "Offset" are all the same thing?

here's a rip from Nucoda's manual on the tool;

Density is Printer Lights ganged together and a density reset makes each of the RGB Printer Light values neutral. Density works the same as the Brightness tool in Brightness/ Contrast and is also known as offset in some other systems.

This control affects all pixels equally, regardless of luminance, color or position. Its affect is similar to camera exposure and it is useful for adjusting the source image dynamic range to a pleasing level. Since it does not squeeze or stretch the dynamic range it causes no artifacts and is a great control to start grading raw or flat scanned images.

 

 

 

And in Photoshop this is the "Constant" slider in Channel Mixer. Or the Brightness/Contrast tool set to legacy mode. 

Edited January 31, 2018 by cameronrad

[Amada Daro]

2 hours ago, dermot.shane said:

i get all that - but where's the advantage to the "printerlights" ui?

 

There are no printer light UI in DaVinci Resolve, but Offset are similar controls and gives control over both density (brightness) and the individual color channels. I might misunderstood the questions? 

[cameronrad]

Just now, Amada Daro said:

There are no printer light UI in DaVinci Resolve, but Offset are similar controls and gives control over both density (brightness) and the individual color channels. I might misunderstood the questions? 

There are "Printer Light Hotkeys" in resolve, they just adjust the offset tool. 

[dermot.shane]

my thoughts ran to why would someone prefer useing the num pad in 2018 to adjust exposure rather than useing a knob to get to the same place much faster + more interactive feedback?

as to the tools themselves, i turn to them first on any system, no matter what they are called....

 

Edited January 31, 2018 by dermot.shane

[Amada Daro]

Good point, not that precise for small increments but should be able to map each channel and the global control to four knobs. 

[dermot.shane]

one disadvantage of using the numpad ui is not being able to adjust say red down and blue up interactivly, you can adjust one -or- the other, and unless you have near endless time, you will never know how much better you could have made the image.. that interactivity thing

a worth tradeoff for precision? i'd say yes,  i use those tool early in the stack /layer / node tree, aim is to normiise the image cleanly there

For me precsion comes in later, the race is not won in the first corner, the grade is not finished in the first stack / layer /node

on all the surfaces i use when working in Resolve (Advanced/Mini/Elements/Color) they are mapped already, some better than others, not sure about Wave/Micro/Ripple tho

under Baselight, Color & Elements both offer the functional equliivent, as does Slate/Blackboard

under Nucoda Elements offers the functional equliivent, as does Precision

no idea about Luster and Scratch, id be surprised if exposure is not avb on a knob / ring / ball of some sort..

Edited January 31, 2018 by dermot.shane

[Nicolas Hanson]

How can I change the offset increments to half etc in the menu? 

[Anton Meleshkevich]

More (mathematically) correct way is to adjust gain knob in linear gamma. It's almost similar to adjusting exposure in RAW.
Long way - convert from log to linear (not rec709 which is sometimes called linear). Then adjust gain. Then from linear convert to log again.
Or you can just set node gamma to linear and set timeline colorspace to the colorspace of your footage.

[Craig Harris]

On 7/18/2018 at 7:32 AM, Nicolas Hanson said:

How can I change the offset increments to half etc in the menu? 

Once the Printer Lights hotkey's are turned "ON" you can use hotkeys to make full, half, and quarter adjustments. I recently added a Stream Deck to my setup and programmed the printer lights to it, which makes the process much faster.

[Nicolas Hanson]

Cool, it looks great! Will check out stream deck! Can full, half etc be configured in the software menus as well?

[Craig Harris]

Just now, Nicolas Hanson said:

Cool, it looks great! Will check out stream deck! Can full, half etc be configured in the software menus as well?

The DaVinci menu simply shows you what hotkeys control the various printer light steps. With Stream Deck, you can configure that any way you like with deep menus. Hope that helps. 

[Nicolas Hanson]

Great thanks!