Home Forums The Learning Center Color Theory and Mixing Which Blue is the real Blue?

Viewing 15 posts - 1 through 15 (of 64 total)
  • Author
    Posts
  • #462113
    crazyfly
    Default

        I’ve heard it said in training videos that there is no true blue, that all blues lean yellow or red. I don’t believe this is true. If I go to Photoshop and in color picker in rgb color space, or here http://web.stanford.edu/class/cs101/image-rgb-explorer.html and slide blue to max and green and red off, look, it’s BLUE. So my question, what paint color (like cobalt blue) is closest to blue? Neither yellow nor red tinted, neither warm nor cool, just blue? And yellow? And red? Sorry if I opened a can of worms, thanks for your help.

        #696157
        Richard P
        Default

            Ultramarine blue is closest. On that colour picker put the blue at 255, and then the green and red at 128. See how it looks purplish?

            #696127
            crazyfly
            Default

                Ultramarine blue is closest. On that colour picker put the blue at 255, and then the green and red at 128. See how it looks purplish?

                Interesting, and unexpected. Not true blue because it’s got red and green, but also not warm or cool because both red and green are equal.

                #696119
                Delofasht
                Default

                    Your criteria for a true blue is matching against a sensation of blue, that sensation will be different for different people.

                    - Delo Delofasht
                    #696113
                    Patrick1
                    Default

                        It sounds like you’re asking what is the psychological unique blue (no apparent leaning to either green or red). Of the single-pigment colors, probably Cobalt Blue or Phthalo Blue (Red Shade) for most people.

                        #696142
                        Humbaba
                        Default

                            Take a Prism, decompose light through it, you should see the true blue. Try to capture this blue and using nature make a copy of it.

                            #696137
                            Gigalot
                            Default

                                You might need Blue Laser beam to match proper zonal color of blue. No one real pigment have zonal blue color. Zonal interference filter can cut whole spectrum except blue line that you want. But hypothetic “zonal blue” pigment will be extremely dark. It can be even darker, that regular ivory black paint because it can reflect any light except an extremely short part of spectrum. So, if you like superior blue, go to laser illumination because even BLUE LED diodes have green and violet part in their light. :)

                                #696128
                                crazyfly
                                Default

                                    I honestly thought I was asking a simple question. Now I need a dictionary and a physics degree. :)

                                    #696148
                                    Pinguino
                                    Default

                                        The B of RGB is not real blue. It is not real blue on old-fashioned cathode ray monitors, and is not real blue on modern LCD flat panels. In fact, the B is two different colors (at least) on these technologies.

                                        That’s because there is no “real blue.” On the other hand, there is a “unique blue” determined by experiment using human subjects with normal color vision. They are asked to choose from numerous colors, and say which of them is what the subject would call a true blue. Different subjects provide different answers. The results can be averaged. Same applies to unique red, unique yellow, and unique green.

                                        Note that the unique colors are not necessarily spectral colors. In particular, no laser-red color meets the human criterion for being the reddest red. It’s psychological.

                                        If you have color-managed software (including Photoshop, GIMP, and some others), with a correct color profile *.icc file on a calibrated and profiled monitor, and are viewing under standard lighting conditions (odds are against that), then within limits the software knows which combination of RGB is needed to produce a theoretical color. But it still cannot produce “real blue” and many other colors, unless you have special, very expensive equipment.

                                        Likewise, in CMYK subtractive mixing (as with printing), Only the Y and K are reasonably close to theoretical colors. The C and especially M are merely approximations, based on best available ink technology. Print software knows this, and adjusts the amount of inks correspondingly.

                                        By “real blue,” do you mean the color of a dark, daylight sky? Sorry, that’s not entirely blue.

                                        If you would like five persons to agree on a color that you offer as “real blue,” do this: Purchase a 6-pack of beer. Open one for yourself. Then offer 5 others a bottle of beer, if they are willing to agree that your blue is “real blue.” I do not know of any other method that would be likely to work.

                                        #696143
                                        Humbaba
                                        Default

                                            I honestly thought I was asking a simple question. Now I need a dictionary and a physics degree. :)

                                            If you want your life simple, get the following blues:

                                            Ultramarine Blue
                                            Prussian Blue
                                            Cobalt Blue

                                            Those are the blues needed to paint portraits, Still Life, and Landscapes.

                                            #696158
                                            Richard P
                                            Default

                                                If you want your life simple, get the following blues:

                                                Ultramarine Blue
                                                Prussian Blue
                                                Cobalt Blue

                                                Those are the blues needed to paint portraits, Still Life, and Landscapes.

                                                As with everything to do with painting.. I disagree. ;)

                                                #696120
                                                Delofasht
                                                Default

                                                    Problem with simple answers is that they are rarely perfect correct answers. Any of us can specify this blue or that one, but we are very likely to disagree. It is better for you to identify that which is closest to a true blue for you, and then go with that. Even more complicated is that in physical paints you will find that something that might look perfect out of the tube suddenly changes hue when tinted, glazed, or mixed with other pigments. Worse yet, many colors labeled blue are closer to cyan right our of the tube, only looking blue because they are a dark valued paint out of the tube (see Phthalo or Prussian Blue which lean pretty heavily toward Cyan and PB15:3 is even used as primary cyan in many CMYK printers). True blue is only a sensation of blue compared to other colors and colors out of a tube will always be darker than the color you need because pigments absorb light, unlike that emitted from a monitor, which as explained above by Pinguino does not even have a pure proper blue either.

                                                    In short, echoing Patrick here, Cobalt or Phthalo Red Shade are generally considered close to a commonly accepted “true” blue, but Pinguino nails it with the six pack approach to generally accepted color. I drink microbrews usually, but will accept just about any beer you offer if it only costs me agreeing with your true blue.

                                                    - Delo Delofasht
                                                    #696159
                                                    Richard P
                                                    Default

                                                        I drink microbrews usually, but will accept just about any beer you offer if it only costs me agreeing with your true blue.

                                                        [ATTACH]859655[/ATTACH]

                                                        #696116
                                                        musket
                                                        Default

                                                            Cobalt.

                                                            #696149
                                                            Pinguino
                                                            Default

                                                                Cobalt.

                                                                No beer for you. :smug:

                                                              Viewing 15 posts - 1 through 15 (of 64 total)
                                                              • You must be logged in to reply to this topic.