In photography an increase in saturation can DECREASE contrast
It is mind-boggling, judging from the opinions presented on the internet, the lack of understanding regarding color saturation in photography. Most of the so-called experts seem to be mindlessly reciting mantras they have heard somewhere without understanding the topic. They all self-confidently proclaim that an increase in saturation INCREASES contrast. In reality, when two colors are similar in that in both colors the same element of the RGB (red-green-blue)components dominates, an increase in saturation DECREASES contrast; but when two colors are dissimilar in that in one color one element of the RGB dominates while in the other color another element of the RGB dominates, an increase in saturation INCREASES contrast. This is important because so many photos of persons are wrecked by an excess of contrast between two similar colors such as on a person's face.
In digital photography colors are composed of a mix of R for red, G for green, and B for blue values. I here prove to you that when two colors both feature the R value being dominant, or when two colors both feature the G value being dominant, or when two colors both feature the B value being dominant, an increase in saturation results in a DECREASE, not an INCREASE in contrast between the two colors; and when two colors feature in one color one of the rgb values being dominant and in the other color another of the rgb values being dominant then saturation INCREASES contrast between the two colors.
All except one of the definitions of saturation I found on the internet I found to be incomprehensible; they all sounded as if someone was reciting a mantra he had memorized that he did not understand. The definition I found to be comprehensible was:
"What is saturation, and why it is so important?
The saturation defines the level of pureness or a color. by a mix of the tree primary colors - red, yellow and blue (or Red, Green and Blue in the common RGB color space). The more a color is saturate, the more it is close the one of the primary colors : theoretically, if you raise the saturation to its upper limit the photo would be composed by just red, green and blue."
-- http://www.juzaphoto.com/eng/articles/color_management.htm
From my personal experience I have seen how an increase in saturation makes a color in which the R value is dominant more red. From working with HTML I have seen what the photography gurus seem to fail to understand, which is that in shades of gray, the R G and B values are equal. The photography gurus all agree that as saturation is decreased the colors draw closer to being shades of gray as you can see working with saturation on a photo editor.
Thus when there is zero saturation, or shades of gray, that means that in each color, the difference between r and g and b, is zero, ie rgb(192, 192, 192), rgb(127, 127, 127), rgb(67, 67, 67). This means (my personal inference) that as saturation is decreased, the differences in the r and the g and the b in the color decrease as the r g and b values all draw closer to an average of the r and the g and the b values in the color.
As saturation is increased, the difference between the r g or b element that is strongest in the color and the other colors in the rgb trinity is increased, as I can tell from my own personal experience and from the quotation from www.juzaphoto.com included above.
Thus, an increase in saturation will DECREASE the contrast between two colors both of which have say the r component amongst r g and b dominating the g and b components; and an increase in saturation will increase the contrast between two colors when one color has say the r component dominating the g and b components, and the other color has say the b component dominating the r and g components.
Take for example two colors found in a man's face. One is rgb(210,131,118); the other is rgb(233,164,135). In both colors the r dominates. The difference between the r's is 23, between the g's is 33, between the b's is 17 for a total differential of 73. If, increasing saturation, you push the r's half way to the maximum 255, and the g's and the b's half way to the minimum of 0, you end up with the first color being 232,65,59 and the second color being 244, 82, 67 so that the difference between the colors has declined from 73 to 37, a decrease in contrast. Check out what these colors look like in even a simple program the internet gurus are too good for such as Microsoft Paint and you can see the decline in contrast with your own eyes.
Again, take for example two numbers 249 and 55; the difference between the two is 194. Push 249 half way to 255 and you get 252, push 55 half way to 255 and you get 155; the difference between the two numbers declines from 194 to only 97.
Yet again, take for example two numbers 150 and 100; the difference between the two is 50. Push 150 half way to 255 and you get 202, push 100 half way to 255 and you get 177; the difference between the two numbers declines from 50 to only 25.
Now take two colors, with one featuring the R or red component dominating the G and B components, and the other featuring the B or blue component dominating the R and G components, say rgb(210,131,118) and rgb(55,85,121). The difference between the r's is 155, between the g's is 46, and between the b's is 3, for a total differential of 204. If you increase saturation pushing the first color's dominating r value half way to 255 and the first color's g and b values half way to zero you change the first color to 232,65,59. If you increase saturation pushing the second color's dominating b or blue value half way to 255 and the second color's r and g values half way to zero, the second color changes to 27,42,188. The overall differential between the two colors becomes 205 in the r's, 23 in the g's, and 129 in the b's for a total of 357, whereas previously the total differential was only 204, and the contrast INCREASES instead of decreases because in this case in one color the R value dominates and in the other color the B value dominates.
I find it significant and incredible that the digital photography world has apparently failed to understand this key point, that increasing saturation decreases contrast between two similar colors while increasing contrast between two dissimilar colors. Many of my photos of humans were unacceptable using a digital camera that a short while ago sold for $600 but now sells for only $100 (I wonder why?)--until I cured the hyper-contrast in the face portrayed, by increasing saturation and then brought the tint back to normal. Using this camera, my photos of a person would make the person look like a different person from photo to photo. Photos of humans can be wrecked by hyper-contrast between two similar colors in a person's face resulting from a lack of saturation, but all you ever hear from the internet photography gurus is that increasing saturation INCREASES contrast.
I confess to being proud that I, an amateur dabbler, have been able to figure out how a lack of saturation can result in hyper-contrast, without any help from anyone, so as to make fools of the photography gurus who proclaim that increasing saturation increases contrast. Too bad the employers are so mindlessly concerned with credentials, experience, and coddling those whom the rude refer to as 'dorks', that they de-emphasize all kinds of important qualities and under-value persons such as myself.
@2006 David Virgil Hobbs
In digital photography colors are composed of a mix of R for red, G for green, and B for blue values. I here prove to you that when two colors both feature the R value being dominant, or when two colors both feature the G value being dominant, or when two colors both feature the B value being dominant, an increase in saturation results in a DECREASE, not an INCREASE in contrast between the two colors; and when two colors feature in one color one of the rgb values being dominant and in the other color another of the rgb values being dominant then saturation INCREASES contrast between the two colors.
All except one of the definitions of saturation I found on the internet I found to be incomprehensible; they all sounded as if someone was reciting a mantra he had memorized that he did not understand. The definition I found to be comprehensible was:
"What is saturation, and why it is so important?
The saturation defines the level of pureness or a color. by a mix of the tree primary colors - red, yellow and blue (or Red, Green and Blue in the common RGB color space). The more a color is saturate, the more it is close the one of the primary colors : theoretically, if you raise the saturation to its upper limit the photo would be composed by just red, green and blue."
-- http://www.juzaphoto.com/eng/articles/color_management.htm
From my personal experience I have seen how an increase in saturation makes a color in which the R value is dominant more red. From working with HTML I have seen what the photography gurus seem to fail to understand, which is that in shades of gray, the R G and B values are equal. The photography gurus all agree that as saturation is decreased the colors draw closer to being shades of gray as you can see working with saturation on a photo editor.
Thus when there is zero saturation, or shades of gray, that means that in each color, the difference between r and g and b, is zero, ie rgb(192, 192, 192), rgb(127, 127, 127), rgb(67, 67, 67). This means (my personal inference) that as saturation is decreased, the differences in the r and the g and the b in the color decrease as the r g and b values all draw closer to an average of the r and the g and the b values in the color.
As saturation is increased, the difference between the r g or b element that is strongest in the color and the other colors in the rgb trinity is increased, as I can tell from my own personal experience and from the quotation from www.juzaphoto.com included above.
Thus, an increase in saturation will DECREASE the contrast between two colors both of which have say the r component amongst r g and b dominating the g and b components; and an increase in saturation will increase the contrast between two colors when one color has say the r component dominating the g and b components, and the other color has say the b component dominating the r and g components.
Take for example two colors found in a man's face. One is rgb(210,131,118); the other is rgb(233,164,135). In both colors the r dominates. The difference between the r's is 23, between the g's is 33, between the b's is 17 for a total differential of 73. If, increasing saturation, you push the r's half way to the maximum 255, and the g's and the b's half way to the minimum of 0, you end up with the first color being 232,65,59 and the second color being 244, 82, 67 so that the difference between the colors has declined from 73 to 37, a decrease in contrast. Check out what these colors look like in even a simple program the internet gurus are too good for such as Microsoft Paint and you can see the decline in contrast with your own eyes.
Again, take for example two numbers 249 and 55; the difference between the two is 194. Push 249 half way to 255 and you get 252, push 55 half way to 255 and you get 155; the difference between the two numbers declines from 194 to only 97.
Yet again, take for example two numbers 150 and 100; the difference between the two is 50. Push 150 half way to 255 and you get 202, push 100 half way to 255 and you get 177; the difference between the two numbers declines from 50 to only 25.
Now take two colors, with one featuring the R or red component dominating the G and B components, and the other featuring the B or blue component dominating the R and G components, say rgb(210,131,118) and rgb(55,85,121). The difference between the r's is 155, between the g's is 46, and between the b's is 3, for a total differential of 204. If you increase saturation pushing the first color's dominating r value half way to 255 and the first color's g and b values half way to zero you change the first color to 232,65,59. If you increase saturation pushing the second color's dominating b or blue value half way to 255 and the second color's r and g values half way to zero, the second color changes to 27,42,188. The overall differential between the two colors becomes 205 in the r's, 23 in the g's, and 129 in the b's for a total of 357, whereas previously the total differential was only 204, and the contrast INCREASES instead of decreases because in this case in one color the R value dominates and in the other color the B value dominates.
I find it significant and incredible that the digital photography world has apparently failed to understand this key point, that increasing saturation decreases contrast between two similar colors while increasing contrast between two dissimilar colors. Many of my photos of humans were unacceptable using a digital camera that a short while ago sold for $600 but now sells for only $100 (I wonder why?)--until I cured the hyper-contrast in the face portrayed, by increasing saturation and then brought the tint back to normal. Using this camera, my photos of a person would make the person look like a different person from photo to photo. Photos of humans can be wrecked by hyper-contrast between two similar colors in a person's face resulting from a lack of saturation, but all you ever hear from the internet photography gurus is that increasing saturation INCREASES contrast.
I confess to being proud that I, an amateur dabbler, have been able to figure out how a lack of saturation can result in hyper-contrast, without any help from anyone, so as to make fools of the photography gurus who proclaim that increasing saturation increases contrast. Too bad the employers are so mindlessly concerned with credentials, experience, and coddling those whom the rude refer to as 'dorks', that they de-emphasize all kinds of important qualities and under-value persons such as myself.
@2006 David Virgil Hobbs
posted by David Virgil at 6:37 AM
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