Wall colors for color grading

[Prahlad Strickland]

I have a new space I'm working on,
I had originally planned to go a charcoal / grey roof with fabric over the acoustic insulation. But it's a low ceiling so I kind of want to use black for the roof and grey for the front wall / side walls.

Question is, will the black fabric on the roof have a negative effect on my eyes white balance while color correcting?

Any experience / suggestions would be creating appreciated.

Prahlad

 

[Phil Holland]

In my old office, I went 18% gray on the surrounding walls. Depending on the room and ceiling height, it likely doesn't matter what's up there as you will typically keep the room darker. Black, white, gray, whatever. If you have a big display that is getting closer to the ceiling I'd favor gray or black.

You might not even need gray walls if they are already white and your monitor is facing "into the void" if that makes sense, meaning facing into the room rather than into the wall.

The more important thing in my opinion is be mindful with any lights in the room. Try to keep them one color temperature, I prefer daylight, but mostly keep the lighting ambient so there are no point sources to irritate your eyes.

Lighting in my whole home is that way and it does make a difference for darker viewing experiences and long work days.

 

[Dermot Shane]

Quote from Daniele Siragusano:

put up a 5 nits grey patch, and see if it is roughly the same brightness as the background.If they do not match you need to calibrate both monitor and surround

read the thread at LGG:
https://www.liftgammagain.com/forum/index.php?threads/pantone-d65-stickers.12095/#post-120761

end game is if you want/need to view a image with accuracy, then you need accurate wall color, accurate bias lighting, acurate monitoring - they exist as a whole, one falls down, they all fall down...

but the defination of accurate is subject to the real world use case, screeening rushes at home may not call for the same level of accuracy as shipping masters from a gradeing suite

 

[Prahlad Strickland]

In my old office, I went 18% gray on the surrounding walls. Depending on the room and ceiling height, it likely doesn't matter what's up there as you will typically keep the room darker. Black, white, gray, whatever. If you have a big display that is getting closer to the ceiling I'd favor gray or black.

You might not even need gray walls if they are already white and your monitor is facing "into the void" if that makes sense, meaning facing into the room rather than into the wall.

The more important thing in my opinion is be mindful with any lights in the room. Try to keep them one color temperature, I prefer daylight, but mostly keep the lighting ambient so there are no point sources to irritate your eyes.

Lighting in my whole home is that way and it does make a difference for darker viewing experiences and long work days.

Thanks Phil, this is great info, cheers..

Prahlad

 

[Joel Voelker]

If you want to get really geeky (and expensive), this is proper:

https://www.rpimaging.com/store/manufacturers/gti/munsell-neutral-gray-paint.html

Keeping the room as neutral as possible and using very accurate 6500 degree lighting is critical. Either buy proper bias lights or invest in something lite Litegear Literibbon to light the room. That way you'll have a flicker free, dimmable solution for setting a proper ambient light level.

 

[Joel Voelker]

Or you can go cheaper. The good folks at FSI cooked up (or found elsewhere) a Behr formula for paint

http://flandersscientific.com/tech-resources/

 

[Björn Benckert]

Datlight balanced lights and neutral shades of gray. A red or green sofa in the room can very much spoil the whole thing. To me the level of gray on walls or such does not matter much if they dont reflect in the screen Always nice to be able to turn off/on the ”grade” setting for the suite as if you sit in there for long days the ash gray with cold lights is not going to make you last long.

Get the philips hue light system then you can swap between different temps and dim all light togeter or individually and make presets etc and run it all from an iphone or ipad.

My workspace is half floor to cealing windows with the streets outside and then I got thick gray lightblocking curtains so if I sit and work late at night or do stuff that is not about color I can open up and get rid of the cave feel that so many suites suffer from. Something I really recommend, as even if you are a full time colorist its nice to be able to open up when conforming or doing other stuff, just to remain sane

 

[Marc Wielage]

MixingLight.com did a series of articles basically on how to build a room purpose-built for color correction, and they hit on a lot of important points:

https://mixinglight.com/color-tutorial/anatomy-of-a-grading-suite-design/

[Note this is a pay site, but I think it's worth paying the small fee to get access to what they discuss here.]

SMPTE has done several good papers on designing rooms specifically for evaluating color video images:

SMPTE RP166-1995 Critical Viewing Conditions
SMPTE ST2080-3-2017 HD Viewing Environment

If you're seriously getting into this, read these papers.


As for paint, either the N7 or N8 Munsell paints work fine:

https://www.rpimaging.com/munsell-neutral-gray-paint.html

To me, calibration and lighting are more important than paint, but everything is imporant (at least in small steps). Every piece of furniture in our room is black or medium gray, and the carpet is dark gray as well. God help you if you walk out into the hallway, but the room itself is pretty neutral.

 

[DJ Meyer]

Whatever you do, do not set it up like it is in every DaVinci Resolve marketing image.

 

[Drew Thomas]

In my old office, I went 18% gray on the surrounding walls. Depending on the room and ceiling height, it likely doesn't matter what's up there as you will typically keep the room darker. Black, white, gray, whatever. If you have a big display that is getting closer to the ceiling I'd favor gray or black.

You might not even need gray walls if they are already white and your monitor is facing "into the void" if that makes sense, meaning facing into the room rather than into the wall.

The more important thing in my opinion is be mindful with any lights in the room. Try to keep them one color temperature, I prefer daylight, but mostly keep the lighting ambient so there are no point sources to irritate your eyes.

Lighting in my whole home is that way and it does make a difference for darker viewing experiences and long work days.

Phil, all the lights in your home are daylight balanced? I tried some 5600 LEDs and it just felt so cold to me in my house so I went back to 2800-3400 in the house. Did it take some getting used to?

 

[Marc Wielage]

Whatever you do, do not set it up like it is in every DaVinci Resolve marketing image.

Your image did not come through for some reason, but I think I would agree with your point on this BMD promotional shot:

Green lighting on the walls? What? And then there's this guy with all the windows open...

I would yell at the lady in the first picture about the coffee cup on the console. We have a strict "no open containers" rule in our color rooms. Especially with coffee.

 

[CaitlinColema]

Recently made a room for my photographs. I want to tell you that pay attention not only to the roof and walls, but also to the floor. Now there are concrete patios in san jose, which can significantly improve the lighting by displaying light.

 

[Adriano Castaldini]

Hi everyone,
I have a similar question.
My grading wall is painted with Munsell N5, and the backlights (on the reference-oled-tv's rear) are CRI 99. BUT... for various reasons I HAVE TO place a big object very near the reference-tv: it's a big cylinder (h 100cm, ø 50cm) with a fabric cover that surely will influence my eyes. I can choose between three colours for the fabric: a “generic” white cylinder, a “generic” anthracite-grey, or a “generic” black.
I don't have a deep knowledge about color science, but intuitively I'd go for black. The reason is that I suppose that anthracite-grey has its heaviest influence on my eye's shadows/mids range. I can suppose (but perhaps I'm wrong) that more the area of the image on tv is bright, less the anthracite cylinder should be influential.
For the same reason, I'd avoid white as well, since a white cylinder should be more influent when grading a bright area of the image.
A black cylinder should be influent mostly on very dark areas of the image on tv, but I usually tend to desaturate the very darks.

Is that so? Should I go for black fabric?

Thanks in advance.

 

[Blair S. Paulsen]

Black yes. Theoretically a "perfect" grey would be better, but the fabric available to you could easily be warmer or cooler than true neutral. BTW, the black fabric is likely to be a little purple, due to common dying techniques, but as long as its reflectivity is low its unlikely to bias your perception. YMMV.

Cheers - #19

 

[Adriano Castaldini]

Black yes. Theoretically a "perfect" grey would be better, but the fabric available to you could easily be warmer or cooler than true neutral. BTW, the black fabric is likely to be a little purple, due to common dying techniques, but as long as its reflectivity is low its unlikely to bias your perception. YMMV. Cheers - #19

MANY thanks Blair!
To be honest I found THIS website and also THIS one. I could buy some fabric to make a sort of “cover” for the cylinder near the tv. The first site says “neutral grey” without any spec. whilst the second site gives you the possibility of specify the CMYK values.
Two questions:
1. In your opinion is a reliable solution? (I mean... can I trust this kind of product?)
2. Which are the CMYK values for Munsell N5??? (I guess it's not 0 0 0 50...)

About the 2nd question, the problem seems to be not only the difference between “theoretical” grey and “perceptual” grey, but also between different interpretations of “perceptual”:
HERE we see Munsell N5 is sRGB 124 124 124, that CONVERTED becomes CMYK 0 0 0 51.
But in THIS document page 32, you see that Munsell N5 is RGB 125 121 127 that CONVERTED becomes CMYK 2 5 0 50.
Whilst a 3rd SOURCE says that “neutral grey” is RGB 137 142 140 or CMYK 4 0 1 44.

In conclusion... which actually is the damn real CMYK equivalent of Munsell N5? Which are the CMYK values I should communicate to the fabric producer?

Thanks in advance.

 

[Marc Wielage]

In conclusion... which actually is the damn real CMYK equivalent of Munsell N5? Which are the CMYK values I should communicate to the fabric producer?

If you read the actual SMPTE spec (SMPTE ST 2080-3:2017), all it says is "A surround of defined luminance/illuminance is necessary for the correct perception of contrast in the displayed image. The surround provides a fixed neutral visual reference that prevents the eye from changing adaptation level." So they don't specify a shade of gray per se, only that it has to be neutral. The point is to have some color-balanced light from behind the monitor so your eyes don't get tired over a period of time.

After having used Munsell N5 paint on the walls in our previous room, we decided that was a little too dark, so we went to N7 in our current room and I think it's about right. What is the nature of this cylinder near the monitor? What exactly does it do? Can it not be moved to a corner of the room, out of your line of sight?

 

[Adriano Castaldini]

The point is to have some color-balanced light from behind the monitor so your eyes don't get tired over a period of time.

Hi Marc! Thanks for Your kind reply. Light from behind the monitor is good (99 CRI D65).

What is the nature of this cylinder near the monitor? What exactly does it do? Can it not be moved to a corner of the room, out of your line of sight?

If you saw my super-tiny-micro studio... The cylinder is a big bass trap (1m x ø45cm), and it's right in the angle of the room, but my room is 16 m3 (2,5 x 2,5 x h2,8) so even if the cylinder is on the angle, it's still in my line of sight. So the only thing to do is making a thin fabric cover in neutral grey. For this reason I need the CMYK values of the neutral grey.

So they don't specify a shade of gray per se, only that it has to be neutral.

That's the point! Infact my question simply is: what does “neutral” mean in CMYK values? Is it the “arithmetic” 0 0 0 51? Or the “perceptual” 2 5 0 50? Or 4 0 1 44? All these variants have more or less the same shade of grey, but they “interpret” how to be neutral in different ways... Which one is right for the fabric?

OK, let's image that you don't have a wall behind your monitor, let's image you have a curtain... Which CMYK values do you communicate to your fabric printer?

 

[Marc Wielage]

OK, let's image that you don't have a wall behind your monitor, let's image you have a curtain... Which CMYK values do you communicate to your fabric printer?

We fake it. My take in the real world is that it doesn't really matter. I ignore what's outside the monitor anyway and it has no bearing on my color correction. Bear in mind I've worked in some crazy rooms for 40+ years, some of which had no backlight, bad backlight, non-neutral colors (like blue or brown or beige), and only in the last 10-15 years have people really started caring about it. The facility I own is the first one I've ever worked in where every light in the room is 65D and we have neutral walls and high ceilings, and the backlight is 65D. The speakers are black but I ignore them.

We worry more about the pictures than what's around it. Honestly, it makes very, very little difference in the real world. I know people who have open windows and open doors and all kinds of light spill, and yet somehow they manage to turn out good-looking shows and commercials week after week.

 

[Simon Dunne]

https://www.bristolpaint.com/paintcategories - these alchemists can mix colour correctly