I want 18% middle gray what do I tell the paint guy at home depot?

jtm6 said:
You need to lower your expectations. The days of walking into a hardware store and talking to someone who can actually help are over, especially at Lowe's.....Do your research beforehand to understand how to make true 18% paint. ..... Don't go there with questions. Go there knowing exactly what you need. ..... Listen to that inner voice. 🙂
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Haha great post. Listen to you inner voice. Nice. My inner voice is very cynical. I've been trying to be more positive lately. You sound like me about 6 months ago. I know. Denial. hahaha

Yes Im trying to do research how to make 18% paint thats what this thread is about and I think Im getting close. ahahahahah This is too funny.

"Dont go there with questions" haha thats awesome. and of course true.
 
Peter_wrote: said:
...
so what would be 100% white? something that reflects 100% of the light. that wouldn't be something like a white colour at all, but something like a mirror.
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Oh yea I hadn't thought of that.

I knew about texture but Im assuming we are talking about unpolished painted residential darkroom walls.

Nice artwork! 🙂

So how much of the light does pure semigloss white on drywall reflect?

and black?

Once we know that we can come up with a ratio and have 18% paint right?

How do you measure reflectivity anyway? If I have a gray wall in my bathroom is there some device you can point at it that tells you "this wall is 23.4% reflective" ?
 
Roger Hicks said:
First of all, 18% grey is nothing to do with the ISO standards for calibrating exposure meters. It's a Munsell mid-tone. That's all.
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Then why do they make such a big deal of using a 'gray card' to check for proper exposure.

You have a board with three big squares. One black square one 18% gray square and one white square. You have someone hold it up and meter the gray quare. Then bracket some photos and write down what the meter said was correct. Then you develop them and see which shot was actually correct (knowing what was black and what was white in the photo) and if it matched what the meter said.

They always say 18% gray card 18% gray card. I never knew why 18% I assume its the card they used when they designed the film and determined its asa to some standardized lighting and exposure settings.
 
Give him a Kodak gray-card and say: "this color!"
Then drive him crazy with your complaints about the not matching color... 😀
 
68degrees said:
Then why do they make such a big deal of using a 'gray card' to check for proper exposure.

You have a board with three big squares. One black square one 18% gray square and one white square. You have someone hold it up and meter the gray quare. Then bracket some photos and write down what the meter said was correct. Then you develop them and see which shot was actually correct (knowing what was black and what was white in the photo) and if it matched what the meter said.

They always say 18% gray card 18% gray card. I never knew why 18% I assume its the card they used when they designed the film and determined its asa to some standardized lighting and exposure settings.
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Many people assume this, generally on the basis of widespread misinformation, and they assume wrong. Read the link I gave and you'll see. The simple truth is that most people have never actually studied sensitometry, or indeed, bothered to think. Instead, they recite half-digested articles of faith. They've studied simplifications of simplifications -- or sometimes, as in the case of the Zone System, complications of simplifications.

There's also the point that NO speed system is geared to a grey, whether 18% Munsell mid-tone or the overall average reflectance of outdoor scenes near Rochester NY (12-14%). Neg speed systems are keyed to the minimum exposure required to give a useful density at a useful contrast; slides and digi are geared to not 'blowing' the highlights to a featureless white. For more about film speeds, take a look at http://www.rogerandfrances.com/subscription/ps iso speeds.html

Also, what are you calling 'black' and 'white'? Both cover VERY wide ranges of reflectance -- and subject brightness range, http://www.rogerandfrances.com/subscription/ps subject brightness range.html , is often more important in any case.

You may also care to take a look at http://www.rogerandfrances.com/subscription/meters and metering.html which is an introduction to metering and contains the following observation Before you read any further, it is important to realize that just about any meter or metering technique can be made to work, as long as you know what you are doing, and as long as the meter isn't broken or defective. Ignore anyone who tells you that their metering technique is the only one that works: this is a subject that attracts a lot of gurus, monomaniacs and armchair theoreticians. The main difference between the different meters and systems is the type and extent of the corrections you need to make with out-of-the-ordinary subjects.

Cheers,

R.
 
I can't be bothered looking it up but it was arrived at by a chap called Munsell in the 19c, who was a tad obsessive with these things, and it was arrived at by finding the average choice of a group of people looking at a range of greys and picking the perceptive mid-tone ... so the answer is the one on the colour-card that looks to be in the middle.

The only really accurate way to asses colour is in a light box with the same colour-value lamps as the environment the object will be viewed in, or with an expensive colour analyser.

Having said the a studio is best with a northern light and painted white ... and any monitors should be set-up Contra-Jure and calibrated under the lighting they will used in.
 
Roger Hicks said:
Many people assume this, generally on the basis of widespread misinformation, and they assume wrong. Read the link I gave and you'll see. The simple truth is that most people have never actually studied sensitometry, or indeed, bothered to think. Instead, they recite half-digested articles of faith. They've studied simplifications of simplifications -- or sometimes, as in the case of the Zone System, complications of simplifications.

There's also the point that NO speed system is geared to a grey, whether 18% Munsell mid-tone or the overall average reflectance of outdoor scenes near Rochester NY (12-14%). Neg speed systems are keyed to the minimum exposure required to give a useful density at a useful contrast; slides and digi are geared to not 'blowing' the highlights to a featureless white. For more about film speeds, take a look at http://www.rogerandfrances.com/subscription/ps iso speeds.html

Also, what are you calling 'black' and 'white'? Both cover VERY wide ranges of reflectance -- and subject brightness range, http://www.rogerandfrances.com/subscription/ps subject brightness range.html , is often more important in any case.

You may also care to take a look at http://www.rogerandfrances.com/subscription/meters and metering.html which is an introduction to metering and contains the following observation Before you read any further, it is important to realize that just about any meter or metering technique can be made to work, as long as you know what you are doing, and as long as the meter isn't broken or defective. Ignore anyone who tells you that their metering technique is the only one that works: this is a subject that attracts a lot of gurus, monomaniacs and armchair theoreticians. The main difference between the different meters and systems is the type and extent of the corrections you need to make with out-of-the-ordinary subjects.

Cheers,

R.
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Oh thats great Roger thanks. Looks like I have a lot of good reading to do. Thank you. Is this your site? rogerandfrances?
 
68degrees said:
Oh thats great Roger thanks. Looks like I have a lot of good reading to do. Thank you. Is this your site? rogerandfrances?
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That's it!

You may also find the following amusing to read first, about why to avoid gurus: http://www.rogerandfrances.com/subscription/ps ignore gurus.html . A quote from it:

Photography sometimes attracts people with a very high opinion of their own expertise, and a predilection for bossing others about. Listen to some of them, and you will be amazed that silver halide photography ever succeeded at all, given that it is so difficult, complicated, and expensive.

Except that it isn't


Cheers,

R.
 
"The Horror."

Trying to emulate ink on paper with paint on ______ (fill in the blank) seems like an exercise in futility. The mythical 18% card is indeed based on reflectivity. Not color alone. For that matter, any color could be used as long as the surface reflects 18% of the incoming light.

I would try to find a locally owned paint store in the hope that the owner knows his craft and actually cares about his service and product. George Kirby IV comes to mind if you are in the Boston area.

Wayne
 
venchka said:
"The Horror."

Trying to emulate ink on paper with paint on ______ (fill in the blank) seems like an exercise in futility. The mythical 18% card is indeed based on reflectivity. Not color alone. For that matter, any color could be used as long as the surface reflects 18% of the incoming light.

I would try to find a locally owned paint store in the hope that the owner knows his craft and actually cares about his service and product. George Kirby IV comes to mind if you are in the Boston area.

Wayne
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Dear Wayne,

Highlight: No, for at least two reasons. First, the sensitivities of films to different colours vary widely, and second, because the sensitivities of meter cells and films can diverge very widely indeed. Consider a meter with a high sensitivity to red (not unusual) and an ortho film with no sensitivity to red...

Cheers,

R.
 
68degrees said:
Id be interested to hear how you would exactly phrase the question if I did inquire there. How would you phrase it? In your own words. Just curious.
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" Have you ever needed to paint a set or wall to match 18% grey, and if so, could you kindly give me the paint formula that was used, or the name of the paint store that mixed the paint for you? Please and thank you."
 
Roger Hicks said:
There's also the question of why a large commercial studio would know or care. When are they ever going to need 18% grey paint?

Cheers,

R.
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I haven't a clue.
However, the OP seems to be getting nowhere with paint stores, so I merely suggested another avenue he might explore.
You are correct in that a studio may not know or care, but it's worth a phone call or email.
 
rbsinto said:
I haven't a clue.
However, the OP seems to be getting nowhere with paint stores, so I merely suggested another avenue he might explore.
You are correct in that a studio may not know or care, but it's worth a phone call or email.
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Highlight: Not really. I started work in a hire studio. We had requests for just about everything -- and as the junior assistant, I did the paint-outs. Black; white; orange, even greys -- but never a request for an 18% grey. In the nine or a dozen books I did for Rotovision, 18% grey backgrounds never came up. It's an obsession of amateurs and Zonies. I mean, yes, it is prima facie a perfectly reasonable suggestion for another avenue, but I'd be truly astonished if anyone had ever tried it.

Cheers,

R.
 
I strongly doubt any studio ever did it (i.e. paint the backdrop or props 18% grey) voluntarily, as mid greys (and 18% is as mid as it gets) are most prone to show up colour casts. There are of course cases where some client has a poor choice of a corporate or product colour scheme, with mid greys in it - but these will have been defined in Pantone, HKS, RAL or whatever, nobody outside camera calibration has ever named a colour by percentage of grey...

In my studio days I've generally avoided mid grey backgrounds like the plague - and in my experience so does anybody further downstream in processing, publication and printing, so that even studio photographers inclined to mid grey backgrounds will soon be told to stop that (elegant, but unprintable) nonsense.
 
rbsinto said:
" Have you ever needed to paint a set or wall to match 18% grey, and if so, could you kindly give me the paint formula that was used, or the name of the paint store that mixed the paint for you? Please and thank you."
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This is the formula I have for Home Depot 18% gray

Behr ULTRA
8 oz. sample
Deep Base
B - 0 - 85
C - 0 - 11
F - 0 - 4
KX - 0 - 170
 
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