!!Peer Project!! Foundational Activities - Learning, Teaching, and Toast ! - Page 12

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# Thread: !!Peer Project!! Foundational Activities - Learning, Teaching, and Toast !

1. Weeeeeeeell, look, this smiley demostrates how i feel and this one and this one i leave with my tale between my legs hehe

2. Hehe, sorry man - didn't mean to or you!

We were just discussing our point of view, same as you were - if you think you're right, try to prove it Even if you're wrong there is still much to be learned from other's thoughts.

3. I hope my post wasn't aggressive. Perhaps I should have left out the part with kinkade. In this context one could think I'm comparing you with kinkade. didn't want to insult you.
nahh... just ignore me if I sound stupid.

anyway back to the topic
http://en.wikipedia.org/wiki/Purkinje_effect
ever read this? I think this is a good start for some new color rules.

4. I didnt know your intentions, and that changes everything, i would have been "right" if your intentions where others, so, keep up the good work

5. I found this really helpful:

HSV (hue, saturation, value), also known as HSB (hue, saturation, brightness) is often used by artists because it is often more natural to think about a color in terms of hue and saturation than in terms of additive or subtractive color components. HSV is a transformation of an RGB colorspace, and its components and colorimetry are relative to the RGB colorspace from which it was derived.

HSL (hue, saturation, lightness/luminance), also known as HLS or HSI (hue, saturation, intensity) is quite similar to HSV, with "lightness" replacing "brightness". The difference is that the brightness of a pure color is equal to the brightness of white, while the lightness of a pure color is equal to the lightness of a medium gray.

http://en.wikipedia.org/wiki/Color_space

Edit, this too:

"Saturation in RGB color space

In an RGB color space, saturation can be thought of as the standard deviation & sigma; of the color coordinates R(red), G(green), and B(blue). Letting μ represent the brightness, then

\sigma = \sqrt{ (R - \mu)^2 + (G - \mu)^2 + (B - \mu)^2 \over 3}.

An example of saturation in layman's terms in the RGB color model is one in which a person has maximum saturation if he or she has 100% brightness in the red channel while having 0% brightness in the other channels; he or she would have no saturation if all the color channels were equal. Thus, saturation is the difference between the values of the channels.

In term of absolute colorimetry, this simple definition in the RGB color space exhibits several problems. The RGB color space is not an absolute colorimetric space; therefore, the value of saturation is arbitrary, depending on the choice of the color primaries and the white point illuminant. For example, the RGB colorspace does not necessarily have an unitary Jacobian in term of absolute colorimetry."

http://en.wikipedia.org/wiki/Saturat...olor_theory%29

6. ## Saturation and Brightness, (again, again)

I'm hoping that most of the questions and objections that have come up should be answered by thinking about these colour relationships in the context of a three-dimensional space. Feel free to raise any of those questions again, but first please take care to read through the points below carefully and in turn:

1. The diagram above shows the gamut of RGB colours arranged in a colour space in which the vertical axis (Y) represents perceived lightness (=tone or luminance). The three views show the same space from different directions. Notice guys that in this space the RGB colours no longer form a simple cube, because the three primaries at full intensity do not have the same tone. This is because different wavelengths of light impress our visual system to different degrees. So no, the simple concept of R, G and B each being at 1/3 of the tone of white, and so on, doesn't work. Maximum green (G255) looks lighter than maximum red (R255), which in turn looks lighter than maximum blue (B255). Among the secondaries, quite logically, maximum yellow (R 255 G255) looks lighter than either red or green, maximum cyan (G255 B 255) looks less light than yellow, but lighter than either green or blue, and maxiumum magenta (R255 B255) looks less light than yellow or cyan, but lighter than red or blue.

Incidentally in my copy of Painter ( 8 ), these differences in tone are ignored, and V is set at 50 % for all colours at their maximum intensity. So V is not tone, and tells you nothing absolute about tone: colours having V = 50 % range in tone from as dark as pure blue to as light as pure yellow. S in Painter is also defined very differently to S in HSB for colours above V = 50 %, so lines of uniform S in Painter are not shading series. Painter's HSV space is not just another name for HSB, but is a completely different system. (Someone please bring me up to date here if necessary).

2. See that the triangular diagram in my brightness/saturation post is in effect a vertical slice into this solid, representing all variations of a single hue, in this case, red. For any hue, the full range of variations can be represented on a similar traingular slice, differing only in shape - the point of maximum chroma will be high in tone for yellow, and low in tone for blue. Strictly speaking I should have put the pure red point a little lower down on my diagram.

3. Any colour that you can see on a screen can be represented by a point in this solid. The position of this point can be described in terms of hue, chroma and tone, or in terms of its RGB components, or in terms of H (hue), S (saturation) and B (brightness). These are just different ways of the specifying the colour using different attributes, not different "theories" of colour.

4. Other colours having the same balance of wavelengths as that colour, and differing only in the quantity of light emitted, will fall along a line originating from the black point, and running through that point. Expressed in terms of hue, chroma and tone, points along this line steadily increase in chroma as the tone increases. In RGB terms, the ratio of R:G:B, stays the same, but the actual numbers for all three components change. In HSB terms the relationship is quantified very simply and directly: all points on the line have the same values of H and S, and differ only in B.

5. As a coloured surface turns away from a white light source, the surface receives less light per unit area and so the amount of diffuse reflection diminishes, but the balance of wavelengths reflected remains the same. Consequently the series of colours we use to represent that surface, which I've been calling a shading series, should follow one of these lines of uniform hue and saturation. Under a coloured light source, the colours should still tend to follow a line of uniform hue and saturation until the terminator is reached, the hue and saturation being determined by the interaction of the local colour of the object and the colour balance of the light source. A small departure might be noticeable where the main light becomes very weak close to the terminator, especially if the secondary light source is of a strongly contrasting colour. Beyond the terminator, both the saturation and the hue may well change dramatically, depending on the colour of the main secondary light source.

6. It might help to understand the colour solid if you think of it as having a ceiling and a floor. The ceiling consists of three planes meeting at three edges, each of which runs from the white point to the yellow, cyan and magenta points respectively. The floor consists of the remaining three planes, which also meet at three edges, running from black to red, green and blue respectively. The ceiling is nothing other than the set of points for which B = 100. There is nothing arbitrary about having "so many" colours with B = 100. The floor is nothing other than the set of points in which S = 100.
The ceiling is particularly important as it marks the upper limit of brightness of every shading series. For example, in a shading series of saturated reds, we can go brighter and brighter until we hit R255 (S = 100); beyond that there simply is no red that is both lighter in tone and still fully saturated. Similarly on every other shading series we can move upwards until we reach B = 100; beyond that point there is just nowhere higher we can go without changing the balance of wavelengths/ ratio of R:G:B/ hue and saturation. The value of B of a colour very usefully tells us where we are in the range of possible values between black and that maximum.

7. Some of the comments that have come up on these matters of basic colour definitions seem to have a subtext along the lines of "but my favourite program can still beat up your program, right?". Painter's HSV I'm sure is a very convenient colour space to use for painting from life; I've said nothing whatsoever to question that. It may well be the MOST convenient space to use for painting from life, for all I know about digital painting (not much). All I've been saying here is that HSB makes it incomparably easier to create shading series, and thereby to create vivid effects of light.

7. Wow, thanks Mr. Briggsy, I really appreciate it and I know it must have taken a lot of time to write this reply as well as the many others. I'm starting to get it haha.

Quick question on #5: "Follow a line of uniform hue and saturation", this meaning that the hue and saturation do not change, or that they change in a pattern? This one in particular has me thinking...

I'm trying to think of the best way to, think about this in terms of simplicity - not just for the new introduction to the Peer Project, but for ease of use @_@.

Should I attempt to explain all the differences between brightness, tone, luminence, value, chroma and saturation do you think?

Or can you think perhaps of a good if not best standard on which to learn? This option seems simpler and less likely to confuse new-comers.

Also, Mr. Briggs - I've become a bit curious now as how you've come to "master" these things, and where did you go to school if you don't mind me asking?

8. thats a great post! Now I think this is showing us the big picture of colorsystems. A complete colortheory needs to include this.

I think it is important that you mentioned the difference between the tone of R,G,B,C,M and Y. I think your explanation why it is like this is incomplete. (But it is correct, no doubt).

I have a theory based on this curve:

http://en.wikipedia.org/wiki/Color_vision

A particular frequency of light stimulates each of these receptor types to varying degrees. Yellow light, for example, stimulates L-cones strongly and M-cones to a moderate extent, but only stimulates S-cones weakly. Red light, on the other hand, stimulates almost exclusively L-cones, and blue light almost exclusively S-cones. The visual system combines the information from each type of receptor to give rise to different perceptions of different wavelengths of light.
Wouldn't this explain why yellow appears to have a higher tone than blue or red? It would also explain why green and orange have the same tone and why red and blue are of lower tone than green.

Nah... but then again this wouldn't change anything from an artist point of view.

@idiot:
Perhaps we need two color theories. The simplified version that explains how it is with links to the real version that explains why.

9. Mr Apathy

1. Would it help if I were to rework these posts into a single tutorial that you could link to more easily? Unfortunately I'm due to disappear under a mountain of undergraduate teaching again at the end of this week, but if it would help I could give it as much priority as possible (short of losing my job!).

2. See if you can write a simplified treatment of colour if you like, but I find these often lead to more confusion than just getting it right in the first place. Better to just organize things progressively, to work up to the more complicated bits step by step.

3. I went to school at the Julian Ashton Art School in Sydney, and I'm still there teaching (hence my name). Ashton's is a great school with a very strong basis in traditional drawing, but to be honest colour was not its strong point at the time I first went there. At its best it taught accurate observation but without a lot of emphasis on understanding, and the prevailing attitudes were mostly along the lines that colour is subjective and can't be taught, that as long as you get the tones right, you could really paint any colours you wanted etc. So really I've learnt about colour by trying to fill in that gap, at first for myself and later for my students. I've been giving regular colour workshops for I guess about seven years, mainly at Ashtons but also occasionally for Disney's Sydney studio (closing down this week, alas), where I was the life drawing teacher for six and a half years. Anything else you want to know? I got a Ph.D in Geology before drawing took over my life, so actually it's Dr Briggsy, by the way.

Originally Posted by Zaknafain
Wouldn't this explain why yellow appears to have a higher tone than blue or red? It would also explain why green and orange have the same tone and why red and blue are of lower tone than green.
Not quite. Colour vision is explained as a combination of the trichromatic model of input to the three cone types, and the opponent model of output to the brain as three colour signals: redness vs. greenness, yellowness vs blueness, and lightness vs darkness. So you can't offer an explanation purely in terms of the cone sensitivity curves; you need to factor in how that lightness vs darkness signal is computed from the cone inputs. The model that I'm familiar with postulates that the lightness signal is obtained by adding the L and M cone responses, with little or no input from the S cones. This is the reason (which I touched on, but didn't go into) why the green screen phosphor, which stimulates both the L and M cones, looks lighter than the red phosphor, which mainly stimulates the L cones, and why both look lighter than the blue phosphor, which only weakly stimulates the L and M cones.

Monochromatic yellow light has the maximum total impact of any wavelength on the M and L cones, which is why yellow looks lighter than any other colour in the spectrum. However the reason why pure yellow looks lighter than either red or green on a computer screen is far simpler, and doesn't require reference to cone sensitivites, opponent signals, or anything, really. In pure yellow on a screen, both the red and the green phosphors are glowing fully, so inevitably it looks lighter than either colour by itself! That very simple explanation is all that is needed to completely account for the tone of yellow, magenta and cyan in relation to R, G and B, and to each other, which is the point I was making.

10. Originally Posted by briggsy@ashtons
However the reason why pure yellow looks lighter than either red or green on a computer screen is far simpler, and doesn't require reference to cone sensitivites, opponent signals, or anything, really. In pure yellow on a screen, both the red and the green phosphors are glowing fully, so inevitably it looks lighter than either colour by itself! That very simple explanation is all that is needed to completely account for the tone of yellow, magenta and cyan in relation to R, G and B, and to each other, which is the point I was making.
However the rest of my post was a good example why I shouldn't post theories that I made up 5 minutes before based on some random internet information.

Stupid me
thanks for your patient explanations. Good to have someone here who knows that kind of stuff.

11. Ha! Dr. Briggs - awesome and geology to boot, seems like that would apply a bit to artistic endeavors as well.

Briggsy, I don't want to create any work for you; you've already done more than enough for all of us. The way I see it, let the others and myself work on organizing and compliling, basically you're the big brain of the outfit - let us do the grunt work.

I'm going to try and write a draft of simple light and color that I hope will be effective and efficent enough for our basic purposes and still try to keep it open to hint at it's complexity, teaching for the effect of learning to teach oneself I suppose. I'll try and have this done soon and it would be great if I could send it to you and get your advice, or if you have any currently.

Sigh, too bad Australia is so far away! Ashtons seems to really be the scratch to my itch. I am at odds with the strict observation only techniques commonly taught, and was taken with your philosophy on the matter.

Out of curiousity, what do you think the practical application, for an artist - is to knowing the underpinnings of light such as you do on what seems to be a more scientific side?

12. It's great to be here Zaknafain. I really love this place.

Sorry Mr Apathy, I forgot about your quick question. Uniform hue and saturation means that both the hue and the saturation stay the same, as for example on lines AZ, AW and AF on that triangular diagram.

13. Ah thanks - that was bugging me haha.

You can call me Tom if you'd prefer -
Mr. Apathy is my fathers name. (Ha... ha... ugh, dumb joke)

http://www.poynton.com/ColorFAQ.html
Oooh, this one too:
http://www.poynton.com/notes/colour_.../GammaFAQ.html

36. WHAT ARE HSB AND HLS?

HSB and HLS were developed to specify numerical Hue, Saturation and
Brightness (or Hue, Lightness and Saturation) in an age when users had to
specify colors numerically. The usual formulations of HSB and HLS are
flawed with respect to the properties of color vision. Now that users can
choose colors visually, or choose colors related to other media (such as
PANTONE), or use perceptually-based systems like L*u*v* and L*a*b*, HSB and
HLS should be abandoned.

Here are some of problems of HSB and HLS. In color selection where
"lightness" runs from zero to 100, a lightness of 50 should appear to be
half as bright as a lightness of 100. But the usual formulations of HSB and
HLS make no reference to the linearity or nonlinearity of the underlying
RGB, and make no reference to the lightness perception of human vision.

The usual formulation of HSB and HLS compute so-called "lightness" or
"brightness" as (R+G+B)/3. This computation conflicts badly with the
properties of color vision, as it computes yellow to be about six times
more intense than blue with the same "lightness" value (say L=50).

HSB and HSL are not useful for image computation because of the
discontinuity of hue at 360 degrees. You cannot perform arithmetic mixtures
of colors expressed in polar coordinates.

Nearly all formulations of HSB and HLS involve different computations
around 60 degree segments of the hue circle. These calculations introduce
visible discontinuities in color space.

Although the claim is made that HSB and HLS are "device independent", the
ubiquitous formulations are based on RGB components whose chromaticities
and white point are unspecified. Consequently, HSB and HLS are useless for
conveyance of accurate color information.

If you really need to specify hue and saturation by numerical values,
rather than HSB and HSL you should use polar coordinate version of u* and
v*: h*uv for hue angle and c*uv for chroma.

Last edited by Idiot Apathy; July 25th, 2006 at 09:07 PM.

14. Poynton's FAQ is a goldmine of technical information, but be careful about taking this extract entirely at face value in the context of practical digital painting. The points about the lack of true device independence and the different computations around 60 degree segments seem to me just reflect the fact that our colour world on the computer screen is RGB space. The point about the inadequacy of computing lightness (not brightness!) as (R+G+B)/3 is absolutely right, but L is a parameter of HLS not HSB. The objection to using polar coordinates (0-360) to designate hue is an objection to the system that used by (I'm guessing) most or all major painting programs, where all we need to do is choose hues, not do calculations. The probable nonlinearity of B in relation to human vision is potentially relevant, though mainly if the nonlinearity is substantially different for R, G and B, but fortunately this factor does not seem to really affect the usefulness of HSB for creating shading series in practice. None of the other objections have any bearing on the fact along a line of uniform hue and saturation, the series of colours all consist of R, G and B in the same proportion, which is what makes the parameter of saturation, as I have been using it, so helpful in generating shading series. Unless I am mistaken Poynton is using the words saturation and chroma interchangeably in the last sentence.

Last edited by briggsy@ashtons; July 26th, 2006 at 11:44 AM.

15. all of this talk totaly defeats my brain. what is it? is this something you should know for oil painting or the fine arts? or are the numbers related to photoshop??

16. Hehehe - Sirkenneth, I'm not entirely sure. I think, perhaps it's something you have to actually understand before you can grasp it's importance - I'm getting a glipse here and there, but yeah... it hurts my brain too.

I would strongly recommend, if you haven't already - to achieve a basic understanding of light and color theory. I think that at least is very vital to art.

17. Originally Posted by Sirkenneth
all of this talk totaly defeats my brain. what is it? is this something you should know for oil painting or the fine arts? or are the numbers related to photoshop??
The important thing to realize, as far as my own recent contributions go, is really very simple: when we paint a coloured surface turning out of a light source, the intensity of the colour diminishes as the tone drops, and does so at a definite rate. Get that relationship right and you can create powerful effects of light. It's very easy to get that relationship right in digital painting programs using HSB, all you have to do is create a series of colours with the same hue (H) and saturation (S), differing only in brightness (B). You can create the same kind of series with oil paints, it just isn't as easy, and I haven't yet gone into any of the methods that can help. Definitely don't get the idea that it is just a matter of physically mixing the colour with black: it doesn't work that way, not by a long shot. (You might start by creating some shading series in Photoshop to start to get a feel for what they look like). If you don't follow that last bit about the theoretical objections to HSB I wouldn't worry, personally; it's a good example of one of the many side issues I've left out to keep things as simple and practical as possible.

18. Mr. Briggsy,

Am I right to assume that a shading series with uniform hue and saturation would only occur in a white-light situation?

Edit:

I've been thinking hard about what terms to use for the PPvol2, what would be best to learn by and to teach with. I'm, really a bit confused with all the terminology, which is of course probably why the terminology come into misuse.

I'd like to at least establish a standard that we can use for the project, it doesn't need to ... perhaps rectify the misuse of terms - but it does need to make sense.

Here is what I use in my mind, I could use your advice - do you see any problems with using these three terms? and/or with their definitions? I wrote these up a week or so ago, before our in-depth discussions. Yeah, I really have no idea what I'm up to, I'm sure there are many flaws and misconceptions in here :|

Value:
A measure of the amount of light (brightness, with it's extreme at white) or the lack of light (darkness, with the extreme being black). I think it is perhaps proper to think, more light = more value, less light = less value. There are of course complications, but I think it still remains basically true. I believe value is the most important factor in the readability not only in form but in an image as a whole. Value is very important and should never be neglected.

From Left to Right, White to Black in 10% increments.

Hue:
Again from WordNet: The quality of a color as determined by its dominant wavelength. Again, get crazy scientific on your own time - I do recommend doing so. Check out the link to howstuffworks.com on light in the Links Archive. With any level of saturation will come hue, and at any value level with the exceptions of white and black hue will exist. Hue can often be a bit hard to discern at lower saturations and lower values, for example - ever seen a dark yellow? A good way to discern hue that I recently learned is a bit of a deduction game. You will of course have a decent idea of what hue any given color is - from here I think it is helpful to ask yourself is it more of this hue, is it perhaps an orange with a tendency towards red, or perhaps yellow? If yes, chances are you have a yellow-orange or red-orange to some degree, if you are positive in saying no - then you have orange. Seems simple but it was a neat revelation to me at the time

From Left to Right: Yellow, Orange, Red, Red-Magenta, Magenta, Violet, Blue, Blue-Cyan, Cyan, Green-Cyan, Green, Yellow-Green and finally white. The white symbolizes that in light these will combine to make white, that and I wanted it proportional . This selection may seem a bit odd to most of you familiar with traditional color wheels, here I have based my choices on the primaries of Red, Green and Blue - Secondaries of Cyan, Magenta and Yellow and Tertiaries as the remainders. I believe this is the most correct representation of light, but again - I'm still working on pinning this all down. I think it is also important to note that violet could perhaps be more properly named as blue-magenta, but what's in a name really?

Saturation:
A measure of how pure a hue is. If a hue is mixed with any other hue it will loose saturation. There are exceptions but only if you are mixing say a low saturation color with a high saturation color - but you will still loose the saturation in your original color. If you say your object is at the absolute maximum saturation possible you are in effect saying that the object is reflecting only one hue and absorbing all others.

Top Bar: From left to right, 100% value 100% saturation Yellow to 100% value 0% saturation Yellow in 10% increments. It is important to note that with 0% saturation it is a misnomer to actually call it yellow, it is in fact no longer color - simply value, white to be exact. This bar would simulate taking your purest yellow paint straight out of the tube and mixing it with pure white, for better or for worse - paint just doesn't work so perfectly.

Middle Bar: From left to right, 60% value 100% saturation Yellow to 60% value 0% saturation Yellow in 10% increments. Again, with no saturation it is actually no longer color only value, we can not properly call this yellow. This bar would simulate taking your purest yellow paint, somehow reducing the value to 60% without reducing saturation and then mixing it with a perfect 60% gray.

Bottom Bar: From left to right, 100% value 100% saturation Yellow to 0% value 0% Yellow in 10% increments. Again, it is no longer color once we have removed saturation, in this case it has become pure black. This bar would simulate mixing your purest yellow paint with pure black paint - and again, for better or for worse, paint just doesn't work so perfectly.

Last edited by Idiot Apathy; July 27th, 2006 at 02:33 AM.

19. I think I've already given an opinion on your first question:

Originally Posted by briggsy@ashtons
Under a coloured light source, the colours should still tend to follow a line of uniform hue and saturation until the terminator is reached, the hue and saturation being determined by the interaction of the local colour of the object and the colour balance of the light source. A small departure might be noticeable where the main light becomes very weak close to the terminator, especially if the secondary light source is of a strongly contrasting colour. Beyond the terminator, both the saturation and the hue may well change dramatically, depending on the colour of the main secondary light source.
As long as one light source is dominant then the balance of wavelengths being reflected sholudn't change until a point at or near the terminator, because the colour balance of the light source doesn't change substantially until that point, and the reflectance curve of the surface is constant. Of course if there are two strong and overlapping coloured light sources that is different: you will get noticeable additive mixing in the overlap.

I'm going to have to get hold of Painter 9 before I can comment on your text, as I gather it must use a completely different definition of V to my Painter 8. In Painter 8 the pure yellow from your third diagram has a value of 50%, not 100%. In fact all of the colours in your middle diagram (excluding white) have basically the same V in Painter 8 (49-50%), showing that V there is not "a measure of the amount of light" or of the perceived lightness. If, as you say, in Painter 9 pure yellow and white both have V = 100%, then V can't be "the amount of light" there either, because white contains more light and looks lighter than yellow. In any case I can't really comment on your efforts until I know the answer to this very important question:

Do you want to make PP2 as simple as possible for Painter users by defining all of your basic colour terms to coincide with the parameters of that program, even though this will be useless or at best highly misleading to people working in Photoshop or traditional media, who use words like value, brightness, and saturation with quite different meanings?

OR

Do you want to begin with the basic colour concepts that are independent of any program or medium, and then explain how those universal concepts relate to the terminology of Painter, Photoshop, and traditional media respectively?

Obviously I hope you decide on the second option. If you stick with the first one it would probably make more sense to put PP2 in the Painter forum.

By the way, have you tried making one of your strips showing a line of uniform hue and saturation yet? I suggest you make a few in Photoshop and compare them with series of uniform S in Painter. That should get the idea across better than any amount of words.

20. Ah sorry, that first question was just something hard to grasp - pretty amazing to think about now... this changes some things... drastically

Painter 8 and 9 are just about the same as far as the color wheel goes. I think painters definition of value is just as broken, or mislabeled. It again seems to just be a system of uniform measurement on a computer rather than human perception. It does seem to be set up perhaps more for chroma to me, which could be nice. All colors that would be 100 S 100 B in Photoshop are 100S 50 V in Painter - I think this makes a little sense; being that one pure spectrum doesn't contain as much light as white, but it breaks down for many other reasons.

Value, was sort of my learned "academic" vocabulary - I didn't get it from HSV. I'm not strongly attached to the word and if there is a better label with less confusion attached to it that would probably be best.

As far as what I want to do for PP2;

Obviously option two I don't even use painter these days; and option two just plain makes sense. That was kind of what I was trying to do with value hue and saturation, but value and saturation can have so many meanings it seems whether they are right or wrong. Yes, lets use traditional academic terms, and how to translate them into photoshop.

Thanks Briggsy!

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My vote would be for the second option please Briggsy. Keeping free of any specific program for the foundation would greatly help those of us who have been confusing different approaches and terminology.

If painter requires V to be 50 in order to get pure yellow, or if V always is white at 100 and black at 0, it sounds like a HSL model.

With your establishing a standard Idiot Apathy the term value may be confusing if people think with a HSB/HSV approach, as value when used in HSV is the same as brightness in HSB, which will only produce that range with 0 saturation. Luminance or Tone are the other descriptions I’ve read in this thread. I would use tone in preference to Luminance because HSL could make luminance as confusing as V or B. –Assuming I’m not alone that is. At least for now I’d say tone, a week ago I’d have said brightness!

I’m finding this thread fantastic. Too much 3d work and RGB colour maths has left me a little stuck in how I’ve been viewing things. Really nice to see a colour cube arranged for perceived luminance (I nearly said brightness).

Thanks for taking the time to clarify this.

-FB

22. Thanks, IA. I did have the wrong idea about your degree of attachment to Painter. Here are some quick comments on your text:
1. You seem to be defining value as a synonym of tone/luminance, but using it as a synonym of brightness (when you assign V = 100% to both yellow and white).
2. I think that in the long run it will cause less confusion than otherwise if you deal with the saturation (= purity) vs chroma (= intensity) issue. The triangular diagram of reds that I posted makes the tone/brightness and saturation/chroma issues fairly clear - feel free to repost or rework it if you like (of course).
3. In the context of digital painting it would be fair to say that a fully saturated colour contains only one or two of the primaries of light (not just one hue necessarily).
4. The difference between colours in the digital world and mixing physical paints opens up a whole other can of worms - tread very carefully there!

Originally Posted by frumpy_bunyin
Firstly I should apologise, otherwise I’ll never be able to do one of Briggsy’s colour workshops!
Do you mean the five-day course at the Julian Ashton Art School in Sydney this December 18-22 and again on January 15-19? The one for only $330 AUS? Don't worry mate, you'll get most of it here for free eventually, way things are going. 23. True - there was a time I was deeply in love with painter After all, it was really valuable at a time when I actually had no concept of tone, hue or saturation etc. Seriously, no concept . 1: (Measure of light?) Is there a term that would encompass white being at the top, black being at the bottom and pure 100B 100S hues falling somewhere inbetween? I view this term in my mind to have little to be seperate from color, as if everything was converted to grayscale. To be honest, I think most people involved with the actual exercises won't even have a concept of HSB, HSV or any other system. I think what we need is a term to help people establish the right amount of light for say, full light vs reflected light etc. and way to describe how to fix it. So I'm thinking, tone? 2: I think I was still a little bit confused myself as to the difference of saturation and chroma. However, if we are seperating light into 3 terms - is chroma perhaps a little redundant and therefore potentially confusing? I can picture a situation where the "student" has the right tone(?) perhaps but not the right "purity" of hue - so saturation would be a better term perhaps to aid a student? However, I think chroma - the concept of chroma is something that should also be conveyed but perhaps more as a mechanism of light and not a instructional term? 4: Hmm yeah... I should take the bits about mixing paint out hahaha... Thanks as always for being patient and putting up with this untrained bumpkin. "Do you mean the five-day course at the Julian Ashton Art School in Sydney this December 18-22 and again on January 15-19? The one for only$330 AUS?"

Quit teasing me, Austrailia is too far away...

24. This is such a great thread! I decided to help myself and join in the fun. Seems like a great way to learn more about color. I'll do the practices one by one, and try to get some feedback from you guys.

Here goes number one!
First try:

I was actually surprised at how much darker my colored ball was. I was expecting the saturated reds to become more light when they would be grayscaled. But Obviously, I was wrong

Second try:

I also tweaked the grayscale version to give myself a bit of a challenge. The result is a bit better although I'm still surprised how much white I needed for the highlight spot to make this look like my grayscale version. Also the red ball seems a bit flat in the greyscale version

Third try:

This would seem about right. Although I had to switch to greyscale in between to get a feel for where I needed more less dark or light spots. But At least I wasnt that far off this time. I didnt vary anything with the hues, I might give that a try next time.

There is so much white in that ball, Im surprised it's perceived as red. Is it possible to make the ball more intense red, while still keeping the same values as the greyscale version?

25. The first balls (which are actually shown on the bottom) turned out too flat and too BLAH (needed intensity) so I made the set (shown on the top) to be more vibrant.

26. mir
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I did two tries on one of the excercises.The second time I thought the things are clearer in my head but when I begin I messed it even though I tried to number my values first and was thinking to make the color more cooler at the distance but couldn't quite succeed.Anyway if I understand the things I think the former objects should be more intense and the distant more saturated.I think the most things I understand from the Idiot Apathy' picure.There it is clear the change of value and saturation in big shapes but.May be it will help if I mix my colors first and think how I will use each mixture in its place.I used prussian blue and yellow light for the first one and white,for the second again prussian blue and orange.
I felt the second was worse and I turned them into greyscale it is really worse.Those values

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Originally Posted by briggsy@ashtons
Do you mean the five-day course at the Julian Ashton Art School in Sydney this December 18-22 and again on January 15-19? The one for only \$330 AUS?

Don't worry mate, you'll get most of it here for free eventually, way things are going.
That's the one! It makes me want to take all of December off and go back to Oz for it.

Found an interesting link on colour histograms, (or at least to me)
http://www.cambridgeincolour.com/tut...istograms2.htm
And have also been toying with some photographs tring to see where I percieve relative colour luminance as it equates to greyscale tone.
I keep wanting to see more contrast in greyscale to match what I see in colour.
The botom picture in that link is interesting, with the red petals against green I feel like they shold still pop out of the background as much in greyscale as in colour. The green hardly seems to change, it's more like I notice the red going, but not the green, I guess there's a fair bit of red in the grass, but no blue or green in the flowers.
Out of curiosity I took a couple of pics I had, split out the RGB to individual channels and multed them down one by one, and recombined them to try get a lumanance ballance to match what I percieved in the colour. I'm a bit uncertan of the result, I'm wondering if I'd be better off with a lut/curve per channel as opposed to a mult.
It was interesting though to compare the result to a desaturation, it seemed a better match to mult RGB by .3 .59 and .11
I'm looking forward to the contents of your colour course being on here soon!

Cheers,

-FB

28. I'm finding it pretty hard to wrap my head around this whole value thing.

I gotta couple questions that'll hopefully clear some things up.

One thing is from the definitions of value and saturation I dont see what the difference is between them. If Sat is the purity of a color then whats the impurity? Most times I've seen it mentioned it was white or black. Which seems to me to be value. So value is just the greyscale with a color added?

What I think it might be is value is a term only useful in relation to the whole image and not to a single color. This is the reason for the B&W value scale renders I've seen guys do then colorize for pieces right? Value determines the colors overall readability within the entire image. Its what seperates one color fromthe next and lets them pop.

So value becomes the end result of sat. Is that anywhere near right?

29. Hi all,
I'm going to be joining in with this now, hope it's not too late and everyone has disapeared. Here are my spheres.
This is a fantastic thread idiot, I've learnt so much reading just the first few pages. thanks.

My red one was way too dark, trying again now.

30. argh still to dark

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