Colour Grading “Continuum”

Alex (whose face will feature heavily in this post) and I wrote and filmed “Continuum” for a uni assignment back at the start of the year. Watch it here (this version is not the same grade as will be described below):

Originally, it was shot with the intention of being black and white, but I decided to play around with the footage much later in DaVinci Resolve. I took an early shot from the film and started to play around with it.

Continuum_flat

The above is a still of the raw footage of a shot from early on in the film. I used the CineStyle picture style alongside Magic Lantern on my Canon 60D in hopes that it would give me a more grade-able image. By that I mean more dynamic range and a higher bit rate. However, I haven’t found any noticeable difference when increasing the bit rate. For me, the only difference was a larger file size. I will experiment further with this at a later date.

In DaVinci, I did the basic simple things such as lowering the shadows, setting the Gamma and raising the highlights. Thus, increasing contrast.

Continuum_contrast


Then I applied a 3D LUT (Look Up Table) on a new serial node (Atl + S) from the top menu.

new_node

 

Applying the LUT:

applying_LUT

As far as I understand, you would normally apply a LUT first so that you can quickly see the “potential” of the raw footage without having to do much initial correction. However, the LUT I used was an emulation of film (as in celluloid film). After doing some research (here’s a link to an informative blog post about LUTs), it seems that these film emulations are used to see what the digital image will look like when printed to film. However, I liked the look it gave me as a starting point.

Initially it was way over the top.

too_much_LUT

I fixed this by using the “Key” panel in Resolve to essentially turn the opacity down and lessen the effect of the LUT.

Key_window

Changing the Gain in the Key panel resulted in this:

less_LUT

I’m guessing a more skilled or professional colorist wouldn’t have used a LUT, but instead used that as inspiration and achieved a similar look manually.

I’ll be doing a lot of research into colour grading in the coming months so I’ll see if my guess is right.


After this I was looking at my scopes and the image and decided I wanted more contrast and a less saturated look. To do this I would use a technique called the Bleach Bypass. This is a technique commonly used in both movies and photography. A famous example is Saving Private Ryan.

In DaVinci Resolve it is done by creating a Layer Node (Alt + L), and removing all saturation from one of the layers.

add_layer_node

Then changing the Composite Mode to Overlay.

composite_mode

 

The origin of this technique comes from the development of celluloid film. A quote from an old ASC article (1998) explains it: “The procedure of bleach bypass entails either the partial or complete skipping of the bleaching function during the processing of a film.” I don’t know much about the processing of film other than black & white 35mm photography film.

That explanation doesn’t mean much to me.

However, after a small amount of googling it seems that what happens is the silver particles in the film are left behind along with the colour dye. Normally the silver would be stripped. The result is a black and white image over the top of a colour image. Not so surprisingly, this is exactly what is done in the digital domain.

This is the result of the bleach bypass technique.

bleach_bypass_result

At first the effect is a little strong, so I increased the saturation back again and decreased the contrast on the black and white node (the bottom node out of the two in the layer node).

bleach_bypass_less_contrast_more_saturation

bleach_bypass_less_contrast_more_saturation_RESULT

Again, I want to mention that I am probably doing these techniques in the wrong order. So don’t take any of this as gospel. I’ll keep researching and learning about the proper techniques as I go along.


At this point I’m happy with the way it looks. But I noticed that the colour balance is a little off.

Scopes_high_blues

Looking at the scopes (which you must do regularly), you can see that the shadows (bottom of the upper graph, far left of the lower graph) on the blue channel are higher than the others. The red shadows are lower. To correct this I simply dragged the Lift wheel on the Primaries page in colour wheel panel. You could also do this on the Shadow wheel on the Log page.

Right now, I do not know the specific difference. I can guess and can see what they do. But I would like to know what exactly it is they do differently (mathematically).

Colour_wheels

It is easier to only go in one direction on the colour wheels at first, instead of diagonally. It makes it much easier to get your bearings. I heard this tip from Curtis Judd on his youtube video on correcting colour balance in DaVinci Resolve.

However, this correction barely made a noticeable difference. I believe the reason the blues aren’t as wide as the reds is because of the LUT. I deleted that node, removing that correction.

Result+Scopes_corrected_blues


You may have noticed that I completely blew out the highlights in the sky in the background of the image. Whoops.

You learn something everything time you hit the record button, I suppose.

Fortunately, DaVinci has a tool that can help to make this look less jarring and garish. Blown highlights are next to impossible to fix properly, but you can help a little. Ideally I would have exposed properly in the first place (Fix it in Pre, not Post!) and shot raw (as in uncompressed).

highlight_panel

This tool essentially creates a slight gradient with the highlights and/or shadows. Just change the High Soft or Low Soft values until you see your scopes change and then check the image.

My highlights were completely blown so all this was doing was changing white values (255, for example) to greyer values (less than 255). This did make them look less noticeable though.

corrected_highlight_panel


The last thing I did was a add a subtle vignette to the image.

This served two purposes:

#1 Make the blown highlights less distracting.

#2 Draw the eye towards the camera. Although, the composition already does this to some extent.

To do this I made a new serial node, went to the Window (oval shape with an outline) panel and clicked the On button on the circle. This brings up a circular power window.

Power windows are used to apply correction to specific areas.

power_window_1

To change the shape of a Power Window, simply drag the dots on the blue lines.

power_window_2

A vignette (in this sense) is simply darkening the outer edges of an image.

So, instead of brightening the middle image (bad), I inverted the power window so that everything outside of the power window would be effected by corrections. I then darkened the edges of the image by dragging the Gain wheel down (darkening the image).

I then increased the amount of feathering of the Power Window by dragging the pink dots on the outer line. This creates a smoother and less noticeable transition.

power_window_3

Below is the before:

before

This is after:

after

It’s subtle.


That is one shot of the film done (albeit rushed). I’d probably make it brighter, looking back at it. The darkness may suit the film though.

Of course, every single shot doesn’t need the same amount of correction. This was only light correction. I didn’t even do any secondary grades (more on this in another blog post at a later date).

Reminder: This is not the same grade as the uploaded youtube video. I may upload it again with the new grade at a later date.

Links and References

Alex Arditti’s WordPress | http://alwayslovedfilm.wordpress.com/

TechniColor CineStyle | http://www.technicolor.com/en/solutions-services/cinestyle

Magic Lantern | http://magiclantern.fm/

Premium Beat: Colour Grading: LUTs | http://www.premiumbeat.com/blog/color-grading-tutorial-luts-in-davinci-resolve/

IMDb: Saving Private Ryan | http://www.imdb.com/title/tt0120815/

ASC. (1998). Soup Du Jour. Available: http://www.theasc.com/magazine/nov98/soupdujour/pg3.htm. Last accessed 17th May 2014.

 

 

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