Recommended Color Chart for Resolve 11

Is there a preferred color chart that anyone suggests for use with DaVinci's Color Match in Resolve 11?

Thanks.


LC

The BMD demo videos appear to be using this, for what it's worth.

-- Chris

Thanks for the link.


LC

How does one of these work? Is there a video that says how to use one somewhere.


Sent from my iPhone using Tapatalk

I think this is a great addition and a long time need. I have been doing a more manual process for over 15 years in Media Composer using a chart that I have outlined here in a blog:
http://24p.com/wordpress/?p=124

My method only uses the grayscale, but if the Resolve method also looks at the color patches, that's even better! Looking forward to trying this one out. There seem to be better charts for digital cinematography than the Macbeth chart as discussed by Art Adams: http://provideocoalition.com/aadams/sto ... cker-chart

The DSC Labs OneShot chart is designed for video and would be interesting to see if that will be supported in a future release of "chart analysis". Art discusses its use in this blog entry:
http://provideocoalition.com/aadams/sto ... s_oneshot/



Michael

this one ?

Variations on the original Gretag MacBeth (1976)... Probably doesn't much matter which one as long as you have a target value set that matches the card type. I'd wonder about the wisdom of using something labelled Adobe, since its probably intended as an sRGB reference for non-broadcast, non-cinema... print photography or camera-ready layup. The real issue is that all reference charts have to be produced and used correctly in order to work. The media they are printed on have to have the correct reflectance and dye metamerism characteristics, they have to be illuminated evenly and in context. All these things take time, care and patience... and then they age. They can have value, no question, but you are still going to have to use your eyes and judgement.

But its about what it has always been about -- hitting a recognized and published target value, whether its SMPTE color bars (which is the row of colours above the grey stairstep), or some kind of "flesh tone" "I-bar", which is the beige square second from the left in the top row. Does that look like "flesh tone" to you?

Its just another color, I think... of the trillions we can see and reproduce. There's also grass/tree "green" which some people see as yellow and often lands in a part of the vectorscope where there is a target box labelled "Yellow", and then there's sky "blue".... take your pick. Could be more cyan.

Charts aren't actually that valuable in practical use -- nice starting point and there is a certain legal appeal about them -- the bottom line is that they really don't help propel the storyline much... and if you are grading a locked cut of anything -- what is that chip chart doing in the shot? Better check the conform first, because maybe the color is not the biggest problem you have.

jPo

-- Michael

Informative links. Thanks for sharing.


LC

-- jPo

Good point about sRGB.


LC

Charts aren't actually that valuable in practical use -- nice starting point and there is a certain legal appeal about them -- the bottom line is that they really don't help propel the storyline much... and if you are grading a locked cut of anything -- what is that chip chart doing in the shot? Better check the conform first, because maybe the color is not the biggest problem you have.

The issue I've always had is that DPs and camera assistants on a fast-moving set tend to look on charts as an annoyance, and spent little or no time getting the chart in the right place. If it's way off to the side and partly in shadow, the chart is nearly useless; if the set is being illuminated by colored lighting, it's still useless.

I'm glad to get a grayscale chart at the beginning of the day if I'm doing a dailies project and if the seen is (mostly) in the same place, set in the same time of day. The Blackmagic rep I spoke to at NAB pointed out that this feature is intended only as a starting point and totally agreed that there will be situations where it just won't work. Under optimum conditions, it could be OK.

This is the first time I've seen the Macbeth chart be useful in a digital situation. Those colors made sense in a film lab, but I've never found a use for them in video. Grayscale charts, sure. The DSC charts are very good:

-- Marc,

Thanks for the input.


LC

I went to a session with Geoff Boyle at NAB. He made a point that using charts is useful to setup a standard for the media, not a standard for the scene.
He was referring to complaint amongst the colorists, that charts are never in the same light that the scene is in. His point was, however, that a real cinematographer would light the chart with the native light to the media (lets say incandescent) or whatever is the "normal" color temp for the stock as deemed by DoP, and then knowing what the image should be (ie "print the chart grey") and how the light differs in the rest of the scene, he could predict the result of his images.
In layman terms it's a "sunset" problem. Let's say I have my media (film or digital sensor) balanced to the daylight (most sensors are designed to have the best dynamic range when lit by daylight). If I were to white balance to the grey card during the sunset I will have possibly technically correct image, but it will not have a look of the sunset, as the white balance procedure in camera will compensate for warmer light.
I would want to light my chart by the light that is the film stock is rated for, and this way I would compensate for any issues the particular batch of film or the particular sensor would have as far as color rendition is concerned. I would have removed the variable of color temperature, by lighting with the light that the film or sensor are rated to. This way I would correct for any shifts and then reproduce the sunset filmed on the same stock truthfully.
It is TV news mentality to always white balance to grey, and simply white balancing and or using charts and treating them as a colorimetric absolute regardless the intent will cause one to have flat images with neutral greys, and no variation, which might be OK for ENG.

-- Dmitry,

Thanks for the detail.


LC

Out of curiosity, why—in many cases—the exorbitant prices for a color chart?

LC

Completely agree with everything mentioned above.

However I would like to point out the added value of using these charts in:

A. Multicam situations. (at least until ACES becomes a (post)household name)
B. Art reproduction. No point in creatively interpreting what has already been creatively interpreted.

why—in many cases—the exorbitant prices for a color chart?

Fair enough. The answer is that the charts themselves have to be printed to an exact value with an extremely narrow tolerance, at a specific reflectance. The dyes have to be stable enough to stay relatively neutral to each other (metamerism) under the wide range of illuminants that exist in the real world. Pretty sure I've never been on a set that was exactly 3200K or D65 -- usually cross-lit with a bewildering array of practicals -- fluorescent office with halogen or nowadays LED desklamps with day spill flooding half the space, and a candle of hope burning on somebody's prayer alcove. All those non-uniform spectra with absorption interference -- there will be colors in the shot that don't make it to the glass.

Easier demonstration would be to screen grab any or all of the charts illustrated above and print them on a variety of inkjets, or your color laser printer and see what you get. Probably not the same.

We used to telecine something called a "ground glass" at the beginning of a project, and then either daily or weekly to check the relative framing between the telecine XYZ alignment and the cinematographer's eyepiece. I once got a photocopy of a framing chart, and the nonlinearities were laughable -- except, of course, the result was only tears.

. Multicam situations. (at least until ACES becomes a (post)household name)
B. Art reproduction. No point in creatively interpreting what has already been creatively interpreted.

ACES. Not any time soon, and yes, if all the cameras get the same chart at the same time, and one of them isn't picking up a flare or bounce from some random direction... kind of like common sticks for a take -- you have to point the chart /slate in the direction of each camera,... and that's when the light changes and you don't get a match.

Point B. Go into the Louvre and find Room 77 in the Denon wing which contains the Delacroix "Liberty" as well as Géricault's "Raft of the Medusa". You will find a couple of Delacroix's tigers there. If you look at some of the examples that come up on Google, you might think that the ruff (chest) fur of the tigers should be pure white. That is wrong, but its what everybody's pocket digital cameras will do. Of course, if you had a chart, white balanced to the chart, locked the color balance and then framed the tigers you should get a nice buff cream yellow. Delacroix himself probably would have shot anyone on sight if they showed him the "corrected" digital image, because he himself abhorred the idea of anything "pure" titanium white.


jPo

LOL

I never sad it would makes things easier. Just that if you take the time and do the things you need to do, the end result will probably be more color-accurate.

Anyway I'll be sure not to fall in that trap the next time they ask me to shoot professionally in the Louvre.

ACES is pretty popular here in The Netherlands BTW.

today I was looking a scene that had no chart and the slates was illuminated by a flashlight...

good luck in that case for your auto-correct....

I personally do not like the idea... I feel that the 10000 hours of practice I did to learn a craft now is somewhat useless... salvo having the client running here at the end of the day with no money left to "save the project" from a bad color home brewed session...

-- jPo

Thanks for the clarification.


LC

I personally do not like the idea... I feel that the 10000 hours of practice I did to learn a craft now is somewhat useless... salvo having the client running here at the end of the day with no money left to "save the project" from a bad color home brewed session...

Doh, been there done that. Very sad when that happens.

I was just telling a friend of mine that I'd like to jettison everything I did in the first ten years of my career (all standard-def, thankfully), because I could do all of it much better today. I think 10,000 hours of color-correction is where you get to the point where you're useful. In the next 10,000 hours, if you're lucky, you start to get good.

I agree with the premise: that the idea of a color chart being useful is going to depend very heavily on how well the chart is used by the crew. If there's a flashlight, or if it's off to the side... there's a thousand different ways the chart could be completely useless. If they put it right next to the actor's face in the key light, and there's no colored gels or filters being used, you have a chance that it'll be OK. But at best, it's just a starting point.

LOL... that is... making record time doesn't count if you're lost.

jPo