Questions on some basic definitions and concepts.
Hi again, everyone. I have done quite a bit of research but haven't found the answer to two questions. Any help or guidance you can provide will be very appreciated. Here they are: 1. A textbook with a chapter on color theory (the book itself is not about color technology) has a reference for daylight but I haven't been able to find the source for this reference. Here it is: " A full-spectrum light source, as recommended, is one with a color temperature close to 5500 K (D55) that is specifically balanced throughout the visible spectrum. This light source is defined as equivalent to daylight in Washington D.C. (Bureau of Standards) in the month of June, during the hours of 12:00 noon to 1:00 pm, when there is a slightly overcast sky; the CRI of this light source should be 90 or higher. " Do any of you know the source for this reference ? 2. I have been trying to understand the difference between a color model and a color space but haven't found any text or any source that provides a good definition for either one or explains both in a manner that is clear and simple to understand. I am trying to understand the following: 2.a. Is Lab a color model or a color space ? 2.b. Is the Munsell Color system a color model ? In this case is the Lab a color space based on the Munsell color system (color model) ? 2.c. Is RGB a color space ? 2.d. How can I draw graphs comparing the color spaces defined by RGB, Adobe RGB and ProColor ? In case I have a raw file created by a 12-bit and another created by a 14-bit camera, how can I draw a graph depicting the difference in the color spaces of these two cameras ? Thank you again in advance for your help. Joseph.
2a and 2b - Have a look at Color Management & Quality output - Tom P Ashe. 2c - RGB is a sort of colour model. ie you can make almost any colour by mixing a combination of red and green and blue light. If you need to define a colour by its numbers, you need an RGB colour SPACE like sRGB, Adobe 1998 RGB and Pro Photo. 2d - Have a look at chromix.com or look at the colorsync utility on a Mac. Also you can plot Lab_a vs Lab_b in Excel Best Matthew Ward ________________________________ From: Joseph Chamberlain <drjchamberlain@gmail.com> To: "colorsync-users@lists.apple.com" <colorsync-users@lists.apple.com> Sent: Monday, 10 March 2014, 11:41 Subject: Questions on some basic definitions and concepts. Hi again, everyone. I have done quite a bit of research but haven't found the answer to two questions. Any help or guidance you can provide will be very appreciated. Here they are: 1. A textbook with a chapter on color theory (the book itself is not about color technology) has a reference for daylight but I haven't been able to find the source for this reference. Here it is: " A full-spectrum light source, as recommended, is one with a color temperature close to 5500 K (D55) that is specifically balanced throughout the visible spectrum. This light source is defined as equivalent to daylight in Washington D.C. (Bureau of Standards) in the month of June, during the hours of 12:00 noon to 1:00 pm, when there is a slightly overcast sky; the CRI of this light source should be 90 or higher. " Do any of you know the source for this reference ? 2. I have been trying to understand the difference between a color model and a color space but haven't found any text or any source that provides a good definition for either one or explains both in a manner that is clear and simple to understand. I am trying to understand the following: 2.a. Is Lab a color model or a color space ? 2.b. Is the Munsell Color system a color model ? In this case is the Lab a color space based on the Munsell color system (color model) ? 2.c. Is RGB a color space ? 2.d. How can I draw graphs comparing the color spaces defined by RGB, Adobe RGB and ProColor ? In case I have a raw file created by a 12-bit and another created by a 14-bit camera, how can I draw a graph depicting the difference in the color spaces of these two cameras ? Thank you again in advance for your help. Joseph. _______________________________________________ Do not post admin requests to the list. They will be ignored. Colorsync-users mailing list (Colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/matthew%40matthewwar... This email sent to matthew@matthewwardphotography.com
1. Standard Illuminants were created from a pretty large number of differing locations and averaged. Certainly NOT just the daylight in Washington DC at the time specifed. I've got an email from this list a few years back specifying the various locations and I'll see if I can dig it up. But the idea it's one measurement taken in one location at one time doesn't seem correct. 2. My take is a color space is a specific recipe of a color model, a color model is a much broader way to discuss the multiple color spaces. As such I consider RGB a color model like CMYK and Lab. I consider Adobe RGB (1998) to be a color space within the RGB color model. SWOP V2 is a specific color space within the CMYK color model. Best way to compare them visually using graphs or numerically if that's your thing would be with ColorThink from CHROMIX. Andrew Rodney http://www.digitaldog.net/ On Mar 10, 2014, at 8:20 AM, matthew ward <matthew@matthewwardphotography.com> wrote:
1. A textbook with a chapter on color theory (the book itself is not about color technology) has a reference for daylight but I haven't been able to find the source for this reference. Here it is:
" A full-spectrum light source, as recommended, is one with a color temperature close to 5500 K (D55) that is specifically balanced throughout the visible spectrum. This light source is defined as equivalent to daylight in Washington D.C. (Bureau of Standards) in the month of June, during the hours of 12:00 noon to 1:00 pm, when there is a slightly overcast sky; the CRI of this light source should be 90 or higher. "
Do any of you know the source for this reference ?
2. I have been trying to understand the difference between a color model and a color space but haven't found any text or any source that provides a good definition for either one or explains both in a manner that is clear and simple to understand. I am trying to understand the following:
2.a. Is Lab a color model or a color space ?
2.b. Is the Munsell Color system a color model ? In this case is the Lab a color space based on the Munsell color system (color model) ?
2.c. Is RGB a color space ?
2.d. How can I draw graphs comparing the color spaces defined by RGB, Adobe RGB and ProColor ? In case I have a raw file created by a 12-bit and another created by a 14-bit camera, how can I draw a graph depicting the difference in the color spaces of these two cameras ?
On Mar 10, 2014, at 8:43 AM, Andrew Rodney <andrew@digitaldog.net> wrote:
I've got an email from this list a few years back specifying the various locations and I'll see if I can dig it up. But the idea it's one measurement taken in one location at one time doesn't seem correct.
Check the archives for a topic called: The history of Standard Illuminants, June 2011. Posted by John (No last name), it was quite interesting. A portion of what John wrote is below:
The series of D-illuminants was adopted by the CIE in 1971 based on 622 measurements from the early 1960s: 249 at Rochester, NY (Kodak); 274 at Enfield, England (Thorn Electrical Industries); and 99 at Ottawa, Canada (National Research Council). Each of these labs contributed spectral measurements taken with different kinds of instruments measuring at different spectral intervals over slightly different ranges. The data were combined into a master set consisting of averages over 10 nm intervals from 330 to 700 nm from which the average and four characteristic vectors were calculated. The average and first two of these vectors account for most of the variance in the observed data and live on as the S0, S1, and S2 vectors used to calculate the D-illuminants in the CIE standard (see Wyszecki & Stiles, 2nd. Ed., page 146). S0 is the mean, S1 provides a yellow-blue variation relating to cloud cover and inclusion/exclusion of direct sunlight, and S2 provides a pink-green variation which was thought at the time to derive from variations in atmospheric water vapor and haze.
All of this was reported by Judd, MacAdam and Wyszecki, J. Opt. Soc. Am., Vol. 54, p. 1031 (1964) and was incorporated without change into the 1971 CIE standard except for the addition of the formula for illuminant chromaticities in terms of correlated color temperature due to Kelly at NBS (now NIST, Washington, D.C.).
Andrew Rodney http://www.digitaldog.net/
Hi, Andrew. I am trying to find the source or origin of this older daylight definition. I tried to look up the post you referenced below but didn't have any luck. I looked at the list archives for June 2011 but couldn't find a thread under the subject 'The History of Standard Illuminants'. Are you sure this post is from June 2011 ? Thank you, Joseph. On March 10, 2014, at 7:51 AM, Andrew Rodney <andrew@digitaldog.net> wrote:
On Mar 10, 2014, at 8:43 AM, Andrew Rodney <andrew@digitaldog.net> wrote:
I've got an email from this list a few years back specifying the various locations and I'll see if I can dig it up. But the idea it's one measurement taken in one location at one time doesn't seem correct.
Check the archives for a topic called: The history of Standard Illuminants, June 2011. Posted by John (No last name), it was quite interesting. A portion of what John wrote is below:
The series of D-illuminants was adopted by the CIE in 1971 based on 622 measurements from the early 1960s: 249 at Rochester, NY (Kodak); 274 at Enfield, England (Thorn Electrical Industries); and 99 at Ottawa, Canada (National Research Council). Each of these labs contributed spectral measurements taken with different kinds of instruments measuring at different spectral intervals over slightly different ranges. The data were combined into a master set consisting of averages over 10 nm intervals from 330 to 700 nm from which the average and four characteristic vectors were calculated. The average and first two of these vectors account for most of the variance in the observed data and live on as the S0, S1, and S2 vectors used to calculate the D-illuminants in the CIE standard (see Wyszecki & Stiles, 2nd. Ed., page 146). S0 is the mean, S1 provides a yellow-blue variation relating to cloud cover and inclusion/exclusion of direct sunlight, and S2 provides a pink-green variation which was thought at the time to derive from variations in atmospheric water vapor and haze.
All of this was reported by Judd, MacAdam and Wyszecki, J. Opt. Soc. Am., Vol. 54, p. 1031 (1964) and was incorporated without change into the 1971 CIE standard except for the addition of the formula for illuminant chromaticities in terms of correlated color temperature due to Kelly at NBS (now NIST, Washington, D.C.).
Andrew Rodney http://www.digitaldog.net/ _______________________________________________ Do not post admin requests to the list. They will be ignored. Colorsync-users mailing list (Colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/drjchamberlain%40gma...
This email sent to drjchamberlain@gmail.com
Hi, Matthew and Andrew. Please forgive me for taking a little while to respond. I needed some time to absorb and process your answers. I also want to thank you and all others who provided answers to my posts. Your answers have been extremely helpful and I am grateful for them. Matthew and Andrew, I have a better understanding now of the difference between a color model and a color space. I would like to find a definition for both but haven't yet found a single reference that provides a straightforward and simple reference for them. Andrew, I do have your book and find it a great reference for color management. Congratulations and thank you for publishing it. I do own ColorThink Pro and need to learn a bit more about its functions to be able to use more productively. Thank you for recommending it. Can you recommend or suggest a simple way to create a graph comparing the color gamut of different devices such as an Apple 30" LCD Display and an Epson Photo printer ? I would like to demonstrate graphically how one is superior to the other for the purpose of color reproduction and fidelity. Thank you again for all your help, Joseph. On March 10, 2014, at 7:43 AM, Andrew Rodney <andrew@digitaldog.net> wrote:
1. Standard Illuminants were created from a pretty large number of differing locations and averaged. Certainly NOT just the daylight in Washington DC at the time specifed. I've got an email from this list a few years back specifying the various locations and I'll see if I can dig it up. But the idea it's one measurement taken in one location at one time doesn't seem correct.
2. My take is a color space is a specific recipe of a color model, a color model is a much broader way to discuss the multiple color spaces. As such I consider RGB a color model like CMYK and Lab. I consider Adobe RGB (1998) to be a color space within the RGB color model. SWOP V2 is a specific color space within the CMYK color model. Best way to compare them visually using graphs or numerically if that's your thing would be with ColorThink from CHROMIX.
Andrew Rodney http://www.digitaldog.net/
On Mar 10, 2014, at 8:20 AM, matthew ward <matthew@matthewwardphotography.com> wrote:
1. A textbook with a chapter on color theory (the book itself is not about color technology) has a reference for daylight but I haven't been able to find the source for this reference. Here it is:
" A full-spectrum light source, as recommended, is one with a color temperature close to 5500 K (D55) that is specifically balanced throughout the visible spectrum. This light source is defined as equivalent to daylight in Washington D.C. (Bureau of Standards) in the month of June, during the hours of 12:00 noon to 1:00 pm, when there is a slightly overcast sky; the CRI of this light source should be 90 or higher. "
Do any of you know the source for this reference ?
2. I have been trying to understand the difference between a color model and a color space but haven't found any text or any source that provides a good definition for either one or explains both in a manner that is clear and simple to understand. I am trying to understand the following:
2.a. Is Lab a color model or a color space ?
2.b. Is the Munsell Color system a color model ? In this case is the Lab a color space based on the Munsell color system (color model) ?
2.c. Is RGB a color space ?
2.d. How can I draw graphs comparing the color spaces defined by RGB, Adobe RGB and ProColor ? In case I have a raw file created by a 12-bit and another created by a 14-bit camera, how can I draw a graph depicting the difference in the color spaces of these two cameras ?
_______________________________________________ Do not post admin requests to the list. They will be ignored. Colorsync-users mailing list (Colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/drjchamberlain%40gma...
This email sent to drjchamberlain@gmail.com
Hello Joseph, Here are answers which try to supplement the ones already given. D55 as daylight: D55 is not the only reference to "Daylight". Any illuminant with a "D" followed by a number, such as D50, D52, D65, D93, or D100, is daylight. The one you use depends on application; generic graphic arts applications usually select D50 while commercial paint applications are more D65. D55 is often seen as a reference for flash photography. The exact "daylight" (or even another Illuminant such as Illuminant-A) to use for a given application will usually be specified in a standard (such as ISO 3664, ISO 12646, etc) Note 1: The Standard Observer (2-degree or 10-degree) can also be different between applications, but this is just another variable.... Color model, space, system, etc: There is overlap, confusion and some distinctions that can be made in these terms. Pantone and Munsell are often referred as "systems" (Munsell Color System, Pantone Matching System) while RGB and CMYK (any flavour) are most often referred to as "color spaces", but sometimes also as "color systems". However, only RGB, CMYK and Munsell are color spaces, which can be specified in terms of coordinates. Pantone is more of a color collection, in this case as a series of colors which can be obtained by a mix of basic colorants. A further distinction is that Munsell is an absolute color space, like L*a*b*, XYZ, xyY, which can describe any color. This is not true of most RGB and CMYK spaces (and certainly not Pantone). The fact that L*a*b* equivalents of Munsell can be derived does not mean that they are the same space, but since both spaces are absolute, you can always find corresponding values. Note 2: Munsell equivalents of very saturated colors, near the chromaticity diagram periphery, are estimates at best and have not been thoroughly verified. Note 3: L*a*b* equivalents of Munsell colors will be different for different Illuminant/Standard Observer combinations. Note 4: Historically the Munsell system was "renotated" (i.e smoothed) in association with xyY coordinates under Illuminant C. The two systems remain distinct. 12 bit vs 14 bit color space: In principle there should be no differences in the gamut and 3D shape of these spaces (if generated with the same camera and software of course). There may be differences in smoothness within the space. However, I doubt that any 3D color space visualization tool will enable you to see differences, unless the data processing is not well done. Danny Danny Pascale www.babelcolor.com ----- Original Message ----- From: "Joseph Chamberlain" <drjchamberlain@gmail.com> To: <colorsync-users@lists.apple.com> Sent: Monday, March 10, 2014 7:41 AM Subject: Questions on some basic definitions and concepts.
Hi again, everyone.
I have done quite a bit of research but haven't found the answer to two questions. Any help or guidance you can provide will be very appreciated.
Here they are:
1. A textbook with a chapter on color theory (the book itself is not about color technology) has a reference for daylight but I haven't been able to find the source for this reference. Here it is:
" A full-spectrum light source, as recommended, is one with a color temperature close to 5500 K (D55) that is specifically balanced throughout the visible spectrum. This light source is defined as equivalent to daylight in Washington D.C. (Bureau of Standards) in the month of June, during the hours of 12:00 noon to 1:00 pm, when there is a slightly overcast sky; the CRI of this light source should be 90 or higher. "
Do any of you know the source for this reference ?
2. I have been trying to understand the difference between a color model and a color space but haven't found any text or any source that provides a good definition for either one or explains both in a manner that is clear and simple to understand. I am trying to understand the following:
2.a. Is Lab a color model or a color space ?
2.b. Is the Munsell Color system a color model ? In this case is the Lab a color space based on the Munsell color system (color model) ?
2.c. Is RGB a color space ?
2.d. How can I draw graphs comparing the color spaces defined by RGB, Adobe RGB and ProColor ? In case I have a raw file created by a 12-bit and another created by a 14-bit camera, how can I draw a graph depicting the difference in the color spaces of these two cameras ?
Thank you again in advance for your help.
Joseph.
Danny, Thank you for your help and the detailed nature of your reply. Just to clarify, I was under the impression that the Munsell system was a color model. When you say that Munsell, Lab, XYZ and xyY are absolute color spaces, I was aware of it. I was under the impression that Lab, XYZ and xyY were color models and Munsell a color system. Is this not the case ? In other words my impression was that color models were defined by mathematical formulas while color spaces provided different implementations of these color models. Based on your explanation my interpretation was wrong. Is this the case ? Thank you again, Joseph. On March 10, 2014, at 8:58 AM, dpascale <dpascale@babelcolor.com> wrote:
Hello Joseph,
Here are answers which try to supplement the ones already given.
D55 as daylight: D55 is not the only reference to "Daylight". Any illuminant with a "D" followed by a number, such as D50, D52, D65, D93, or D100, is daylight. The one you use depends on application; generic graphic arts applications usually select D50 while commercial paint applications are more D65. D55 is often seen as a reference for flash photography. The exact "daylight" (or even another Illuminant such as Illuminant-A) to use for a given application will usually be specified in a standard (such as ISO 3664, ISO 12646, etc) Note 1: The Standard Observer (2-degree or 10-degree) can also be different between applications, but this is just another variable....
Color model, space, system, etc: There is overlap, confusion and some distinctions that can be made in these terms. Pantone and Munsell are often referred as "systems" (Munsell Color System, Pantone Matching System) while RGB and CMYK (any flavour) are most often referred to as "color spaces", but sometimes also as "color systems". However, only RGB, CMYK and Munsell are color spaces, which can be specified in terms of coordinates. Pantone is more of a color collection, in this case as a series of colors which can be obtained by a mix of basic colorants. A further distinction is that Munsell is an absolute color space, like L*a*b*, XYZ, xyY, which can describe any color. This is not true of most RGB and CMYK spaces (and certainly not Pantone). The fact that L*a*b* equivalents of Munsell can be derived does not mean that they are the same space, but since both spaces are absolute, you can always find corresponding values.
Note 2: Munsell equivalents of very saturated colors, near the chromaticity diagram periphery, are estimates at best and have not been thoroughly verified.
Note 3: L*a*b* equivalents of Munsell colors will be different for different Illuminant/Standard Observer combinations.
Note 4: Historically the Munsell system was "renotated" (i.e smoothed) in association with xyY coordinates under Illuminant C. The two systems remain distinct.
12 bit vs 14 bit color space:
In principle there should be no differences in the gamut and 3D shape of these spaces (if generated with the same camera and software of course). There may be differences in smoothness within the space. However, I doubt that any 3D color space visualization tool will enable you to see differences, unless the data processing is not well done.
Danny
Danny Pascale
www.babelcolor.com
----- Original Message ----- From: "Joseph Chamberlain" <drjchamberlain@gmail.com> To: <colorsync-users@lists.apple.com> Sent: Monday, March 10, 2014 7:41 AM Subject: Questions on some basic definitions and concepts.
Hi again, everyone.
I have done quite a bit of research but haven't found the answer to two questions. Any help or guidance you can provide will be very appreciated.
Here they are:
1. A textbook with a chapter on color theory (the book itself is not about color technology) has a reference for daylight but I haven't been able to find the source for this reference. Here it is:
" A full-spectrum light source, as recommended, is one with a color temperature close to 5500 K (D55) that is specifically balanced throughout the visible spectrum. This light source is defined as equivalent to daylight in Washington D.C. (Bureau of Standards) in the month of June, during the hours of 12:00 noon to 1:00 pm, when there is a slightly overcast sky; the CRI of this light source should be 90 or higher. "
Do any of you know the source for this reference ?
2. I have been trying to understand the difference between a color model and a color space but haven't found any text or any source that provides a good definition for either one or explains both in a manner that is clear and simple to understand. I am trying to understand the following:
2.a. Is Lab a color model or a color space ?
2.b. Is the Munsell Color system a color model ? In this case is the Lab a color space based on the Munsell color system (color model) ?
2.c. Is RGB a color space ?
2.d. How can I draw graphs comparing the color spaces defined by RGB, Adobe RGB and ProColor ? In case I have a raw file created by a 12-bit and another created by a 14-bit camera, how can I draw a graph depicting the difference in the color spaces of these two cameras ?
Thank you again in advance for your help.
Joseph.
Joseph, As I said there is confusion on the terminology and how it is used and I would not bet on a unique set of descriptive words. Munsell is a system which is implemented as a 3D color space (Berns), so whether we call it a space or a system is both OK. I have seen L*a*b* being described as a system (Hunt), and as a color space (Berns). Lets say we agree that Munsell and L*a*b* are color spaces. Then, according to what you wrote, they should be different implementations of a color model. Unfortunately, Munsell does not have mathematical formulas similar to what we have behind L*a*b*. So Munsell is both a color system and a color space and Pantone a color system but not a color space. Munsell and L*a*b* can represent any color using a set of three orthogonal coordinates, so they both are 3D color spaces. There is a one-to-one match between Munsell and L*a*b*, even if this match cannot be mathematically defined (conversions require successive approximations).. Not a simple semantic problem... As for your search for the first reference for daylight illuminants, go to books.google.com search for contributions to color science the article Spectral Distribution of typical daylight as a function of correlated color temperature is in there (plus a lot of other interesting stuff!). Danny ----- Original Message ----- From: "Joseph Chamberlain" <drjchamberlain@gmail.com> To: <colorsync-users@lists.apple.com> Sent: Sunday, March 23, 2014 11:30 PM Subject: Re: Questions on some basic definitions and concepts.
Danny,
Thank you for your help and the detailed nature of your reply.
Just to clarify, I was under the impression that the Munsell system was a color model.
When you say that Munsell, Lab, XYZ and xyY are absolute color spaces, I was aware of it. I was under the impression that Lab, XYZ and xyY were color models and Munsell a color system. Is this not the case ? In other words my impression was that color models were defined by mathematical formulas while color spaces provided different implementations of these color models. Based on your explanation my interpretation was wrong. Is this the case ?
Thank you again,
Joseph.
On March 10, 2014, at 8:58 AM, dpascale <dpascale@babelcolor.com> wrote:
Hello Joseph,
Here are answers which try to supplement the ones already given.
D55 as daylight: D55 is not the only reference to "Daylight". Any illuminant with a "D" followed by a number, such as D50, D52, D65, D93, or D100, is daylight. The one you use depends on application; generic graphic arts applications usually select D50 while commercial paint applications are more D65. D55 is often seen as a reference for flash photography. The exact "daylight" (or even another Illuminant such as Illuminant-A) to use for a given application will usually be specified in a standard (such as ISO 3664, ISO 12646, etc) Note 1: The Standard Observer (2-degree or 10-degree) can also be different between applications, but this is just another variable....
Color model, space, system, etc: There is overlap, confusion and some distinctions that can be made in these terms. Pantone and Munsell are often referred as "systems" (Munsell Color System, Pantone Matching System) while RGB and CMYK (any flavour) are most often referred to as "color spaces", but sometimes also as "color systems". However, only RGB, CMYK and Munsell are color spaces, which can be specified in terms of coordinates. Pantone is more of a color collection, in this case as a series of colors which can be obtained by a mix of basic colorants. A further distinction is that Munsell is an absolute color space, like L*a*b*, XYZ, xyY, which can describe any color. This is not true of most RGB and CMYK spaces (and certainly not Pantone). The fact that L*a*b* equivalents of Munsell can be derived does not mean that they are the same space, but since both spaces are absolute, you can always find corresponding values.
Note 2: Munsell equivalents of very saturated colors, near the chromaticity diagram periphery, are estimates at best and have not been thoroughly verified.
Note 3: L*a*b* equivalents of Munsell colors will be different for different Illuminant/Standard Observer combinations.
Note 4: Historically the Munsell system was "renotated" (i.e smoothed) in association with xyY coordinates under Illuminant C. The two systems remain distinct.
12 bit vs 14 bit color space:
In principle there should be no differences in the gamut and 3D shape of these spaces (if generated with the same camera and software of course). There may be differences in smoothness within the space. However, I doubt that any 3D color space visualization tool will enable you to see differences, unless the data processing is not well done.
Danny
Danny Pascale
www.babelcolor.com
----- Original Message ----- From: "Joseph Chamberlain" <drjchamberlain@gmail.com> To: <colorsync-users@lists.apple.com> Sent: Monday, March 10, 2014 7:41 AM Subject: Questions on some basic definitions and concepts.
Hi again, everyone.
I have done quite a bit of research but haven't found the answer to two questions. Any help or guidance you can provide will be very appreciated.
Here they are:
1. A textbook with a chapter on color theory (the book itself is not about color technology) has a reference for daylight but I haven't been able to find the source for this reference. Here it is:
" A full-spectrum light source, as recommended, is one with a color temperature close to 5500 K (D55) that is specifically balanced throughout the visible spectrum. This light source is defined as equivalent to daylight in Washington D.C. (Bureau of Standards) in the month of June, during the hours of 12:00 noon to 1:00 pm, when there is a slightly overcast sky; the CRI of this light source should be 90 or higher. "
Do any of you know the source for this reference ?
2. I have been trying to understand the difference between a color model and a color space but haven't found any text or any source that provides a good definition for either one or explains both in a manner that is clear and simple to understand. I am trying to understand the following:
2.a. Is Lab a color model or a color space ?
2.b. Is the Munsell Color system a color model ? In this case is the Lab a color space based on the Munsell color system (color model) ?
2.c. Is RGB a color space ?
2.d. How can I draw graphs comparing the color spaces defined by RGB, Adobe RGB and ProColor ? In case I have a raw file created by a 12-bit and another created by a 14-bit camera, how can I draw a graph depicting the difference in the color spaces of these two cameras ?
Thank you again in advance for your help.
Joseph.
_______________________________________________ Do not post admin requests to the list. They will be ignored. Colorsync-users mailing list (Colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/dpascale%40babelcolo...
This email sent to dpascale@babelcolor.com
participants (4)
-
Andrew Rodney
-
dpascale
-
Joseph Chamberlain
-
matthew ward