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  • RGB – what’s the point?

  • John Childs

    Member
    February 21, 2010 at 11:16 pm

    OK, maybe showing my ignorance here, but what is the point of RGB as a colour standard?

    Surely, for any given values, the appearance will vary depending on the type and condition of the screen it is viewed on.

    For example, any given colour will look different on your modern whizzbang flat screen graphics monitor, to what it does on on the old CRT portable telly in my spare bedroom.

    Add in other variables, like the user adjusting the brightness and contrast values, and how can we rely on it to match to vinyl colours?

  • David Rowland

    Member
    February 21, 2010 at 11:23 pm

    exactly, no TV’s are the same (RGB)
    no printers are the same (CMYK)

    For a standard, it is not. It means Red gun in a telly is at 100% power or 0% is off. Solid Cyan is 100% of that colour printed, then fraction it back, but how do we know its that it is the cyan that you intended?

    RAL & Pantone books however are very close between them

    Welcome to colour profiling 😀

    For colour accracy we have two real measurements, one of them defined by LaB and the other by XYZ, these are the primary measurements of Spectrophotometer’s.

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

  • Lee Attewell

    Member
    February 22, 2010 at 5:11 am

    Isn’t it something to do with the larger colour gamut in rgb than is available in CMYK?

    Apparently if you use rgb to design in then you’ll get much more vibrant colours when you go to print.

    Having said that, we mainly use CMYK because Jenny likes to work in that 😉

    And I don’t argue with the designer 😛

  • John Childs

    Member
    February 22, 2010 at 8:35 am
    quote Lee Attewell:

    Isn’t it something to do with the larger colour gamut in rgb than is available in CMYK?

    Apparently if you use rgb to design in then you’ll get much more vibrant colours when you go to print.

    That may well be the case Lee, and I can see that that would be a good thing if you are designing something from scratch.

    But it won’t help us if a client gives us an RGB reference and expects us to be able to match the colour, either to a vinyl or for print. How do we do that?

    It’s not often that we get just RGB from a client but, when it happens, all I can do is to get a rough idea of the colour from MY screen, or the Pantone Colour Bridge book, then send them a sample of what I think is an acceptable colour for approval.

    That’s a long winded process, and really negates the whole point of standards.

  • David Rowland

    Member
    February 22, 2010 at 9:09 am

    if you get an RGB from a client, then tell them it will be near that colour as those colours are really designed for the screen (with exception of Durst Lambada type printers that are actually lasers of RGB)

    So in gamut order:-

    LaB – the widest, tho not suitable for PDF/Postscript files
    RGB – next
    CMYK – Last and can be colour accurate for our purposes

    Then references books like Pantone, as each printer operator and RIP designer is supposed to have printer profiles matched for each media they print on, so when you print a CMYK or Pantone item, you should get the best match from that machine to what you are hoping for.

  • John Childs

    Member
    February 22, 2010 at 9:23 am
    quote Dave Rowland:

    if you get an RGB from a client, then tell them it will be near that colour as those colours are really designed for the screen .

    That’s more or less what I do Dave.

    It just doesn’t seem very satisfactory, or professional. 🙁

    But, if it’s the best we can do, I suppose that we’re stuck with it.

  • David Rowland

    Member
    February 22, 2010 at 9:27 am

    i cant imagine that the client would be a professional design agency giving RGB, that sort of customer is likely to be the all singing designer sitting at home with some web skills and (legit or not legit) version photoshop installed.

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