Cyan = Blue

Discussion in 'Digital Darkroom' started by micah_oliver, Mar 18, 2008.

  1. I am in a trivial debate with someone over the question of if Cyan is the same
    as Blue. I have lurked around the forum and I see many people saying
    'cyan(blue)' or 'cyan-blue'. Are Cyan and Blue the same color?

    This person claims they worked with people in the print industry and overheard
    them use Cyan and Blue interchangeably as it would seem people do here on these
    forums. Does this mean they are one in the same? No matter which color model I
    look at, I can tell a difference, quite notably, between the colors Cyan and
    Blue. What do print/photo professionals mean then they say 'cyan(blue)' or
    'cyan-blue' or 'blue-cyan'??

    The same questions follow for the other colors of the color models.

    Thanks for your help.
  2. Very different. There is a remark about cyan-blue here:
  3. No, cyan and blue are not the same color. Granted , cyan as a color is a SHADE of blue, but really more of a turquoise, and
    I often hear it referred to it as "blue ink" in the press room here where I work, though technically they are not, and should
    not be, interchangeable.

    Cyan is simply one of the primary colors used in process (or "4 color") printing along with Magenta, Yellow and Black (or
    K). If one is referring to "blue" ink, I would have to ask for clarification, as they could mean just the Cyan, or be referring
    to a "spot" color; a Pantone color for example.
  4. So when she was around people in the print industry, and used similar semantics as what I find here, as I have exampled above, was she merely misunderstanding them? Because of her lack of knowledge of the color spaces and the technical jargon which printers use, did she mistakenly think they meant that Blue and Cyan are the same color?
  5. Probably. My best guess would be the people she was around were using inaccurate
    terminology, but everyone "knew what it meant" and it was simply never corrected. For
    example, around here, we have digital presses, and when someone says "blue ink" I know
    they mean Cyan, because there is no blue ink available for those machines. Magenta became
    "red" in the same fashion. I just gave up saying anything.

    The wiki link above has a good explanation of it.
  6. Blue is blue. Cyan is blue green mix. Most definately NOT the same.

    Yellow-magenta-cyan are subtractive primary colors

    Red- green blue are additive primaries.
  7. Process printing uses layers of transparent CMYK inks and/or halftone effects, as opposed to "spot" color, which lays down areas of specific color: if you need medium teal, you use medium-teal ink.

    Printers therefore often speak of "process colors": process-blue (cyan), process-red (magenta), process-yellow (oddly enough, yellow), and, of course, process-black. There is no process-green. I imagine they get tired of saying "process" all the time and just shorten it down.
  8. If you take 2 floodlights, one with a blue gel filter, the other with a green, and play their lights on a white wall so that they overlap, the overlap will be cyan. Add a 3rd floodlight, with a red gel filter, overlap all 3, the overlap will be white. Red, green and blue are the 3 primary colors, from which you can mix any of the secondary colors (magenta, yellow, and cyan), via the above *additive* process. Red+Green yields yellow, Red+Blue: Magenta, and Green+Blue: Cyan. You can arrange the colors like a Star of David:
  9. This looks better:
  10. sorry, too big:
  11. That said, in practice most printing cyans I've seen seem to be significantly more blue than green. In truth Cyan is supposed to be Anti-Red, Magenta Anti-Green, and Yellow Anti-Blue.
  12. I agree. Any of the secondary colors (yellow, cyan, magenta) is the *addition* of it's 2 primary color (red, green, blue) neighbours, and the absence of the primary color across from it, on the star.
  13. I suspect that in the printing industry concentrated cyan dye looks dark blue but as Mendel has shown very clearly they are NOT the same.
  14. The addition of any two primaries (red, green, or blue), invariably produces a "brighter" secondary. Add the third primary, and you've got (brightest) white.

    This is counterintuitive to mixing paints, which is a *subtractive* process. There: mix the three primaries and you get black. The additive process requires floodlights with filters, or similar.

    I took a few lithomasked posterized shots many years back, making multi-exposures on a single frame of slide film, with red, green and blue filters, which is also an additive process, and that helped me undertand this.

    The main reason "The Wizard of Oz" movie survived the years with pristine color was that 3 copies were saved in silver oxide emulsion black and white, one for each of the 3 color primaries. A fresh color version could be re-created by projecting all 3 films simultaneously on the same target, each with the appropriate color filter.

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