IPP2 Contrast and Roll-Off Illustration

[Gavin Greenwalt]

I've seen a lot of uncertainty over what the IPP2 Contrast and RollOff settings are doing so I put together a simple illustration of what's happening under the hood.

Relative to a rec709 output this is graphing what each of the settings is doing to the image. It's pretty simple when you can just look at the curves (like you would use in photoshop). The contrast setting defines an S-Curve to add contrast to the image and the Roll-Off modifies how the top 50% luminance of the contrast curve rolls off to white.

Note: These curves are assuming rec709 is baked in as a starting point vs. the "real" IPP2 curves which include the Log3G10 -> sRGB/rec709 (based on your preferences) display output conversion curve as well. Displaying the full Log3G10 to Rec709 w/ contrast & Rolloff is technically what happens in software but it's in my opinion not as easy to understand from an illustrative standpoint since even the None/None correction would still have a strong curve to it (to convert from Log3G10 to Rec709) and the curves are relatively much more similar in log space. So all of these curves are relative to a None/None Rec709 output.

 

[Mike P.]

Cool, thanks Gavin!

 

[Martin Stevens]

NICE. Thanks, Gavin!

 

[Christoffer Glans]

I'm always using high contrast with very-soft or soft roll-off. The smoothness of the image with very-soft rolloff and high contrast makes the images almost filmlike. It's a shame Resolve still don't have true settings for IPP2 yet.

 

[Mike P.]

I've been doing the same; it's contrasty but still holds colour in the highs...

 

[Michael Tiemann]

I'm always using high contrast with very-soft or soft roll-off. The smoothness of the image with very-soft rolloff and high contrast makes the images almost filmlike. It's a shame Resolve still don't have true settings for IPP2 yet.

I started there (High Contrast/Rolloff 4, but I think mostly because I had been addicted to the Crack that is DC2/RG4. Over time I've been shifting to Medium Contrast/Rolloff 2 and changing my base ISO to put the shadows where I want. Not saying there's a right vs. wrong way, but IPP2 has made such better options available that it's been more rewarding for me to explore.

P.S. philmColor V1 has also been a treat.

 

[Josh Birch]

A while back I came across a thread that demonstrated with picture examples the differences between the IPP2 Contrasts and Roll Off curves, but I can't seem to find it? Any help finding it would be much appreciated!

 

[Christoffer Glans]

I started there (High Contrast/Rolloff 4, but I think mostly because I had been addicted to the Crack that is DC2/RG4. Over time I've been shifting to Medium Contrast/Rolloff 2 and changing my base ISO to put the shadows where I want. Not saying there's a right vs. wrong way, but IPP2 has made such better options available that it's been more rewarding for me to explore.

P.S. philmColor V1 has also been a treat.

I usually create an input LUT for each project based on the general look and environment that was used. Using IPP2 as an output LUT makes it irrelevant if the blacks are crushed by the high contrast since you can easily lift it in the Log3G10 data until you get a pleasing shadow level. The amount of control that IPP2 gives you in grading is awesome.

 

[Marcus Friedlander]

Very useful! Thanks Gavin!

 

[rand thompson]

You can get a nice look from all three with a -1 or -2 log shadow.



Low Con-Very Soft

[/url]low con-very soft by rand thompson, on Flickr[/IMG]


Medium Con-Very Soft

[/url]Med con -Very soft by rand thompson, on Flickr[/IMG]


High Con-Very soft

[/url]High Con-Very Soft Roll-Off_1.1.3 by rand thompson, on Flickr[/IMG]

[/url]Screenshot (125) by rand thompson, on Flickr[/IMG]

 

[Matt Beardsley]

I'm a little late to the IPP2 party, but totally loving it... it's super helpful to see the curves!

 

[Matt Beardsley]

EDIT: accidental double post