The Dimensions of Colour - a colour theory discussion thread - Page 9

Join the #1 Art Workshop - LevelUpJoin Premium Art Workshop
Page 9 of 12 FirstFirst 1 2 3 4 5 6 7 8 9 10 11 12 LastLast
Results 241 to 270 of 333
  1. #241
    Join Date
    Oct 2006
    Posts
    14
    Thanks
    3
    Thanked 0 Times in 0 Posts
    Follows
    0
    Following
    0
    hi david,
    at the site it said,
    "Take a moment at this point to also ensure that you have completely eradicated from your mind every trace of the primary school notion that green is "made of" yellow and blue. Subtractive mixing doesn't work like that. We get a green mixture from yellow and cyan because our components are both in part "made of" green. If any colour can be said to be "made of" yellow and blue, it's white."

    "If any colour can be said to be "made of" yellow and blue, it's white" did you mean it black? cause yellow and blue has not wavelength in common.
    thanks before david.

    Reply With Quote Reply With Quote  


  2. Hide this ad by registering as a member
  3. #242
    Join Date
    Oct 2006
    Posts
    14
    Thanks
    3
    Thanked 0 Times in 0 Posts
    Follows
    0
    Following
    0
    is the additive mixing mean the mixing of two color of light, and subtractive mixing is the mixing of color of light with the color of surface (irrespective with the surface's material)?

    if the subtractive mixing of the light and the surface which the color of them doesn't have the same wavelength is it really result black?
    what if a blue skin creature (like the avatar movie) get pure yellow (R+G) light ? is it result black? i'm confuse with how come if one surface with the light can do subtractive color if the color of light and surface has no similar wavelength... how come it became darker as black? even there is a light...

    thanks before for the helping, david.

    Reply With Quote Reply With Quote  

  4. #243
    Join Date
    Oct 2006
    Posts
    14
    Thanks
    3
    Thanked 0 Times in 0 Posts
    Follows
    0
    Following
    0
    hi
    again david
    now i include the sample of my painting about subtractive and additive mixing
    it says if the red subtract with green surface or blue light subtract with green surface resulting "black" color did you mean by "neutral or gray" color?

    i want to ask, which picture is the correct one sir?

    The Dimensions of Colour - a colour theory discussion thread
    or
    The Dimensions of Colour - a colour theory discussion thread

    and why sir?
    thanks before

    Reply With Quote Reply With Quote  

  5. #244
    Join Date
    May 2005
    Location
    Sydney
    Posts
    832
    Thanks
    189
    Thanked 1,389 Times in 332 Posts
    Follows
    0
    Following
    0
    Ah, trick question! Both additive and subtractive processes are involved. Can you follow this? -

    Attached Images Attached Images  
    Reply With Quote Reply With Quote  

  6. The Following 2 Users Say Thank You to briggsy@ashtons For This Useful Post:


  7. #245
    Join Date
    Oct 2006
    Posts
    14
    Thanks
    3
    Thanked 0 Times in 0 Posts
    Follows
    0
    Following
    0
    hi david, thanks for the explanation
    did you mean by this?
    The Dimensions of Colour - a colour theory discussion thread

    at no 1. i see the green became more yellowish at the diffuse reflection, is that because the RED + GREEN? also the number two, the green became more blue (lets say cyan) is that because G + B?

    then what happened to the subtractive mixing theory that say if between two color that has no wavelength in common will appear black? EX. R + G = Black or G + B = Black?
    or is there any example in real object where we can see this "black" happen between light and surface color?

    what if a yellow surface got blue light?
    The Dimensions of Colour - a colour theory discussion thread
    how the subtractive mixing going on?
    the hue of yellow value is higher than the hue of blue light, is the yellow surface became lower in value if it got blue light?

    could you please include the formula for me like the one u've did before at the upper of this picture?
    The Dimensions of Colour - a colour theory discussion thread

    thanks before david for your helping. i really appreciate that.

    Reply With Quote Reply With Quote  

  8. #246
    Join Date
    May 2005
    Location
    Sydney
    Posts
    832
    Thanks
    189
    Thanked 1,389 Times in 332 Posts
    Follows
    0
    Following
    0
    With subtractive mixing you get the wavelengths that are in common to the two colours, so the result depends on the actual spectral distributions. With a non-monochromatic blue light and a typical yellow surface you're likely to get a green reflection (first example). With a desaturated red light and a typical green surface you might get a slightly more yellowish green than the local colour (second example).

    You might like to try out other combinations yourself with the online applet I used to make these diagrams. Choose the option you want (e.g. "Run with browser Java) and then click and drag on the diagrams to create your spectra.

    http://www.cs.brown.edu/exploratorie...ion_guide.html

    Attached Images Attached Images    
    Reply With Quote Reply With Quote  

  9. The Following 2 Users Say Thank You to briggsy@ashtons For This Useful Post:


  10. #247
    Join Date
    Oct 2006
    Posts
    14
    Thanks
    3
    Thanked 0 Times in 0 Posts
    Follows
    0
    Following
    0
    thanks dave, but i'm not really understand how to used the diagram, the incoming light, reflectance, and product.

    Reply With Quote Reply With Quote  

  11. #248
    Join Date
    May 2005
    Location
    Sydney
    Posts
    832
    Thanks
    189
    Thanked 1,389 Times in 332 Posts
    Follows
    0
    Following
    0
    No problem g. In each set of three graphs, "Incoming Light" represents the spectrum of the coloured light source (I don't know why they didn't add the spectrum colours to that graph - it's a bit confusing), "Reflectance" represents the wavelengths of the spectrum that the colored object can reflect, and "Product" is the result of multiplying those two graphs together, wavelength by wavelength, and represents how much of that coloured light will be reflected by that coloured object. (For example, in the second diagram, for a middle green wavelength we get incoming light (0.4) times reflectance (1.0) gives a product of 0.4, while for an extreme violet wavelength we get incoming light (0.4) times reflectance (0.0) gives a product of 0.0).

    I just made up the reflectance spectra, but they represent rather ideal bright yellow and bright green objects.

    Last edited by briggsy@ashtons; April 25th, 2012 at 08:00 AM.
    Reply With Quote Reply With Quote  

  12. #249
    Join Date
    May 2003
    Location
    Hudson River valley, NY
    Posts
    16,212
    Thanks
    4,879
    Thanked 16,675 Times in 5,021 Posts
    Follows
    0
    Following
    0

    Tristan Elwell
    **Finished Work Thread **Process Thread **Edges Tutorial

    Crash Course for Artists, Illustrators, and Cartoonists, NYC, the 2013 Edition!

    "Work is more fun than fun."
    -John Cale

    "Art is supposed to punch you in the brain, and it's supposed to stay punched."
    -Marc Maron
    Reply With Quote Reply With Quote  

  13. #250
    Join Date
    May 2005
    Location
    Sydney
    Posts
    832
    Thanks
    189
    Thanked 1,389 Times in 332 Posts
    Follows
    0
    Following
    0
    I don't know what it is, but I want one! It's described in the article both as "stone" and "glass" but it looks very pale for a volcanic glass, so it seems more likely to be artificial.

    Very cool site!

    Reply With Quote Reply With Quote  

  14. #251
    Join Date
    May 2003
    Location
    Hudson River valley, NY
    Posts
    16,212
    Thanks
    4,879
    Thanked 16,675 Times in 5,021 Posts
    Follows
    0
    Following
    0
    I suspect it is, although I've seen similar, but less dramatic, effects with moonstone.


    Tristan Elwell
    **Finished Work Thread **Process Thread **Edges Tutorial

    Crash Course for Artists, Illustrators, and Cartoonists, NYC, the 2013 Edition!

    "Work is more fun than fun."
    -John Cale

    "Art is supposed to punch you in the brain, and it's supposed to stay punched."
    -Marc Maron
    Reply With Quote Reply With Quote  

  15. #252
    Join Date
    Oct 2006
    Posts
    14
    Thanks
    3
    Thanked 0 Times in 0 Posts
    Follows
    0
    Following
    0
    yes, the incoming light got no color
    do we identify the color by seeing the highest mount at the diagram?
    let say, what monochromatic blue light beam into monochromatic yellow surface

    does the diagram look like this?
    The Dimensions of Colour - a colour theory discussion thread

    then what the result of product's diagram saying?

    thanks for helping dave.

    Last edited by grapholic; April 27th, 2012 at 03:16 AM.
    Reply With Quote Reply With Quote  

  16. #253
    Join Date
    Jul 2007
    Location
    Valencia Spain
    Posts
    28
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Follows
    0
    Following
    0
    Wow, this is great, thanks for sharing!!!

    Miguel Angel Valenzuela Solís/ Nick: Alenz

    www.alenz01.blogspot.com
    Reply With Quote Reply With Quote  

  17. #254
    Join Date
    May 2012
    Posts
    22
    Thanks
    5
    Thanked 7 Times in 7 Posts
    Follows
    0
    Following
    0

    Thanks, Thanks and again Thanks

    I'm just on page 1 of the web site and I'm a very happy person because I have allways thought of colour as spatial and have created representational paintings based on these theories-once I've fully read the site will post images with theoretical explaination.
    thanks David Biggs

    Reply With Quote Reply With Quote  

  18. #255
    Join Date
    Oct 2006
    Posts
    14
    Thanks
    3
    Thanked 0 Times in 0 Posts
    Follows
    0
    Following
    0
    a very special thanks to Doctor Briggs for give me such a wonderful color study

    now my artwork is getting better and better.
    now i'm more understand about the subtractive and additive mixing
    all this time i was confuse because i was miss the monochromatic intensity about color... when i understand it more... all the mixing suddenly magically fit into the color stimulation.

    i feel that My feelings can not be uttered in words now,
    all my artwork is always dedicated for you doctor briggs
    my respect.

    Reply With Quote Reply With Quote  

  19. #256
    Join Date
    May 2005
    Location
    Sydney
    Posts
    832
    Thanks
    189
    Thanked 1,389 Times in 332 Posts
    Follows
    0
    Following
    0
    Thanks for the encouragement guys. Hopefully you'll be pleased to know I'm planning to work through the site this year, adding some new images and trying to improve the text. I've recently finished revising the two introductory pages:

    http://www.huevaluechroma.com/011.php
    http://www.huevaluechroma.com/012.php

    Attached Images Attached Images            
    Reply With Quote Reply With Quote  

  20. The Following 3 Users Say Thank You to briggsy@ashtons For This Useful Post:


  21. #257
    Join Date
    May 2012
    Posts
    22
    Thanks
    5
    Thanked 7 Times in 7 Posts
    Follows
    0
    Following
    0

    Question

    Thanks again for your fantastic website its excellent!!!!!!!!!!!

    Q.1.What is the logic of a painter "muting" a colour by mixing it with its complementry instead of GRY especially if its NOT to change hue i.e. mixing YEL and BLU for GRN but rather to desaturate it?
    Q.2.Putting aside overly literal abberation of actual pigment and generalising theoretically is it true that you could arrive at a reasonable approximation of say yellow/blue mixed red/violet just by looking for the appropriate hue (if the colour wheel was "blended infinitely")and adding a GRY?

    P.S.I think there is a yellow/orange light from the blue glass stone because the light entering the stone is refracted in internal dispersal therefore the concentrated beam of light that eventually emerges is of a different wavelength and that also means colour difference.But I might be wrong.

    Reply With Quote Reply With Quote  

  22. #258
    Join Date
    May 2005
    Location
    Sydney
    Posts
    832
    Thanks
    189
    Thanked 1,389 Times in 332 Posts
    Follows
    0
    Following
    0
    C.M.

    Glad you like the site. I'm not sure if this answers your first question, but it is possible to find or mix a pigment-mixing complementary for any coloured paint that will neutralize it, but this sometimes will not be the same colour as the additive complementary. For a yellow, for example it will be not blue but a particular violet paint or paint mixture.

    I'm afraid I can't even guess what you mean by your second question, so for me to answer it you'll need to rephrase it completely.

    Reply With Quote Reply With Quote  

  23. #259
    Join Date
    Jun 2012
    Posts
    1
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Follows
    0
    Following
    0

    Thumbs up

    Wonderful & helpful info.
    Thank you very much

    Michelle Elle.

    www.jolini.com
    ______________________________
    The most Beautiful Artwork is YOU.
    Reply With Quote Reply With Quote  

  24. #260
    Join Date
    Oct 2006
    Posts
    14
    Thanks
    3
    Thanked 0 Times in 0 Posts
    Follows
    0
    Following
    0
    hello briggsy
    does this site precise? as you give me the one before?
    http://graphics.stanford.edu/courses...lormixing.html

    Reply With Quote Reply With Quote  

  25. #261
    Join Date
    May 2005
    Location
    Sydney
    Posts
    832
    Thanks
    189
    Thanked 1,389 Times in 332 Posts
    Follows
    0
    Following
    0
    Overall the applets and explanations on that site are very good, but just on that last page you linked to there are a couple of things that could be confusing to students. I don't think it is stressed enough that all actual yellow, cyan amd magenta pigments are of the second, "broad C,M,Y" type, and I doubt that the narrower, essentially theoretical CMY colours in the first applet would be as bright as they are shown. (In fact the displayed colours are definitely not accurate, because when I add light from the red and orange parts of the spectrum to the narrow "yellow" spectrum, the displayed colour gets darker). Also in the summing up at the end, while it is correct to say that the additive/subtractive primaries "don't need to be" R,G,B/C,M,Y respectively, it is potentially misleading not to emphasize that those primaries do give the maximum gamut.

    Reply With Quote Reply With Quote  

  26. #262
    Join Date
    May 2005
    Location
    Sydney
    Posts
    832
    Thanks
    189
    Thanked 1,389 Times in 332 Posts
    Follows
    0
    Following
    0
    I'd like some help to see if a diagram I'm working on is looking right for most observers/monitors.

    Please click on the link and observe each of the two finely-lined squares at the bottom of the diagram from a distance of a couple of metres or so, so that the vertical lines are no longer visible. Please check that your browser is set to 100% zoom, and very importantly, position yourself so that your line of sight to the square you are looking at is at exactly 90 degrees to the screen. If your browser resizes the diagram, please click on it to return it to full size. Do the squares look grey or coloured?

    http://www.huevaluechroma.com/pics/4.3.3.jpg

    Reply With Quote Reply With Quote  

  27. The Following User Says Thank You to briggsy@ashtons For This Useful Post:


  28. #263
    Join Date
    Aug 2005
    Location
    Kansas city, MO
    Posts
    1,167
    Thanks
    1,423
    Thanked 867 Times in 333 Posts
    Follows
    0
    Following
    0
    Quote Originally Posted by briggsy@ashtons View Post
    I Do the squares look grey or coloured?

    http://www.huevaluechroma.com/pics/4.3.3.jpg
    Square (A) looks colored (light purple) Square (B) looks grey to me.

    Jay's CA.org Sketchbook:
    Jay's Conceptart.org sketchbook

    Check out my portfolio:
    http://jasonrossart.carbonmade.com

    Check out my blog:
    http://mind2pixels.blogspot.com

    "Practice" DOES NOT make perfect...
    "Perfect Practice" makes perfect...
    Reply With Quote Reply With Quote  

  29. The Following User Says Thank You to Jason Ross For This Useful Post:


  30. #264
    Join Date
    Mar 2012
    Posts
    706
    Thanks
    519
    Thanked 239 Times in 172 Posts
    Follows
    0
    Following
    0
    Thanks first and foremost for your website, it was extremely informative and has helped me no end in my artistic growth. I am very much grateful.

    I have this idea, I want to desaturate the pure (100% saturation) colours in order to find out their values in black and white as a reminder.

    Would this be possible using the desaturate or greyscale function in ps? Would it be inaccurate or misleading?

    Reply With Quote Reply With Quote  

  31. #265
    Join Date
    May 2005
    Location
    Sydney
    Posts
    832
    Thanks
    189
    Thanked 1,389 Times in 332 Posts
    Follows
    0
    Following
    0
    You're very welcome, and thanks for asking your questions here, Care.

    The answer to your first question is that you can either use the desaturate command in Lab mode (not RGB mode), or convert to greyscale mode, among other methods that achieve the exact same result, i.e. conversion of each colour to a grey of the same "L".

    My answer to your second question is that it seems this conversion may sometimes be somewhat inaccurate or misleading for some colours (mainly high saturation blues), but there may not be any better general solution. Here's why:

    In the attachment each coloured square is on a background of a grey of the same value according to these methods.

    The red square may look at first glance to be lighter than the grey background, but if I squint I can see that it is actually similar, or at least much more similar in value than it first seems. So I think that this is probably just an example of the impression of extra lightness that strong colours seem to possess, which been called "chromatic luminance" or the Helmholtz–Kohlrausch effect.

    However, no matter how much I squint, the blue square still looks lighter to me than the grey surround, so I'd have to say that it actually is lighter. A possible explanation is that the blue "phosphor" of my laptop is less violet/less saturated than that assumed for the conversion, which would make pure blue (B255) relatively bright on my screen, and also pure yellow (white minus blue) a little less bright. So maybe there's no conversion that will be perfectly accurate for all monitors.

    If anyone has any ideas please comment!

    A separate issue is that on most laptops the relative values of the colours and the greys change alarmingly with viewing angle; my observations were made looking flat on to the screen.

    Attached Images Attached Images  
    Last edited by briggsy@ashtons; December 6th, 2012 at 06:52 PM.
    Reply With Quote Reply With Quote  

  32. #266
    Join Date
    Mar 2012
    Posts
    706
    Thanks
    519
    Thanked 239 Times in 172 Posts
    Follows
    0
    Following
    0
    thanks briggs you always come through, i really enjoy how u manage to verbalize things that i suppose we must unconsciously recognize, everytime you explain something i get that aaaa now it makes sense moment...

    like i feared, there might not be an all encompassing way to accurately determine this. but its no big deal. i guess its just a case of learning the exceptions to the rule etc

    Reply With Quote Reply With Quote  

  33. #267
    Join Date
    May 2005
    Location
    Sydney
    Posts
    832
    Thanks
    189
    Thanked 1,389 Times in 332 Posts
    Follows
    0
    Following
    0
    This year my regular classes are (so far) all on late afternoons, evenings and weekends, which means I'll be available to run a few 5-day colour workshops more or less on demand at my studio in Sydney. The focus can be either on theory, or on putting the theory into practice using traditional or digital media. If anyone is interested please email me to discuss suitable dates.

    Here's a still life demo from the first one last week.

    Attached Images Attached Images  
    Reply With Quote Reply With Quote  

  34. #268
    Join Date
    May 2003
    Location
    Hudson River valley, NY
    Posts
    16,212
    Thanks
    4,879
    Thanked 16,675 Times in 5,021 Posts
    Follows
    0
    Following
    0
    Quote Originally Posted by briggsy@ashtons View Post
    In the attachment each coloured square is on a background of a grey of the same value according to these methods.

    The red square may look at first glance to be lighter than the grey background, but if I squint I can see that it is actually similar, or at least much more similar in value than it first seems. So I think that this is probably just an example of the impression of extra lightness that strong colours seem to possess, which been called "chromatic luminance" or the Helmholtz–Kohlrausch effect.

    However, no matter how much I squint, the blue square still looks lighter to me than the grey surround, so I'd have to say that it actually is lighter. A possible explanation is that the blue "phosphor" of my laptop is less violet/less saturated than that assumed for the conversion, which would make pure blue (B255) relatively bright on my screen, and also pure yellow (white minus blue) a little less bright. So maybe there's no conversion that will be perfectly accurate for all monitors.
    The value of that blue looks pretty good to me when I squint (at least equivalent to the red in terms of matching the ground), so I'd say your suspicion about the phosphors is probably right.


    Tristan Elwell
    **Finished Work Thread **Process Thread **Edges Tutorial

    Crash Course for Artists, Illustrators, and Cartoonists, NYC, the 2013 Edition!

    "Work is more fun than fun."
    -John Cale

    "Art is supposed to punch you in the brain, and it's supposed to stay punched."
    -Marc Maron
    Reply With Quote Reply With Quote  

  35. The Following User Says Thank You to Elwell For This Useful Post:


  36. #269
    Join Date
    Nov 2011
    Location
    Arlington, TX, USA
    Posts
    911
    Thanks
    308
    Thanked 418 Times in 362 Posts
    Follows
    0
    Following
    0
    Not sure if this is appropriate place to say it, but I appreciate the feedback on my SB and all the help you've given this community towards questions on color and light, sir.

    Reply With Quote Reply With Quote  

  37. #270
    Join Date
    May 2003
    Location
    Hudson River valley, NY
    Posts
    16,212
    Thanks
    4,879
    Thanked 16,675 Times in 5,021 Posts
    Follows
    0
    Following
    0
    Quote Originally Posted by Elwell View Post
    The value of that blue looks pretty good to me when I squint (at least equivalent to the red in terms of matching the ground), so I'd say your suspicion about the phosphors is probably right.
    Just a followup to that, I'm checking this thread today from a school computer, and the blue looks fine, but the red is appreciably darker than its corresponding gray.


    Tristan Elwell
    **Finished Work Thread **Process Thread **Edges Tutorial

    Crash Course for Artists, Illustrators, and Cartoonists, NYC, the 2013 Edition!

    "Work is more fun than fun."
    -John Cale

    "Art is supposed to punch you in the brain, and it's supposed to stay punched."
    -Marc Maron
    Reply With Quote Reply With Quote  

  38. The Following User Says Thank You to Elwell For This Useful Post:


Page 9 of 12 FirstFirst 1 2 3 4 5 6 7 8 9 10 11 12 LastLast
  • 424,149 Artists
  • 3,599,276 Artist Posts
  • 32,941 Sketchbooks
  • 54 New Art Jobs
Art Workshop Discount Inside
Register

Developed Actively by vBSocial.com
The Art Department
SpringOfSea's Sketchbook