Results 1 to 3 of 3
  1. #1
    Platinum Lounger
    Join Date
    Feb 2002
    Location
    A Magic Forest in Deepest, Darkest Kent
    Posts
    5,681
    Thanks
    0
    Thanked 1 Time in 1 Post

    RGB v CMYK (Excel 97 SR2)

    I belong to a company that has very strict branding regulations in respect to colour of logo's and reports. A team member is compiling a large number of excel workbooks that are being converted into pdf format for publication on our corporate intranet. I have customised her workbooks to have specific colour pallettes and are saved as book.xlt. This fine, no problems if viewed on screen! BUT

    The palettes are in RGB reference and look fine on screen but some of our directors want them in hard copy. Here's the question

    How can I convert/customise the RGB coded palette to recognise CMYK so that we can have printed options of the worksheets?

    Jezza <img src=/S/crossfingers.gif border=0 alt=crossfingers width=17 height=16>
    Jerry

  2. #2
    WS Lounge VIP rory's Avatar
    Join Date
    Dec 2000
    Location
    Burwash, East Sussex, United Kingdom
    Posts
    6,280
    Thanks
    3
    Thanked 191 Times in 177 Posts

    Re: RGB v CMYK (Excel 97 SR2)

    Hi,
    I don't know of any built-in VBA functionality to do anything approaching this. A quick rummage through the MSDN library produced this article, which seems to indicate that you may have a horrendous time trying to achieve this:
    "The process of converting colors from one color space to another is called color conversion. All colors in a color space are fixed relative to the color space's white point. Since the white point of a color space varies from device to device, a converted color must then be matched to its visually closest color in the destination color space. This process is called color mapping.

    For example, if you have a digital image that you created on your display, it may be in a device-dependent RGB color space. If you want to print it on a printer, it must be converted to the printer's color space. Since the printer probably uses a device-dependent CMYK color space, all RGB values must be converted to CYMK. This is color conversion. Once the values are specified in terms of the CYMK space, they need to be matched to the closest color that the printer can produce. This is called color mapping or color matching.

    Both color conversion and color mapping must take into account a number of device-specific factors. For instance, the building blocks of screen images are pixels. Each pixel has a set number of bits to store its color or color index value. The number of bits per pixel depends on the type of display and display adapter being used, and the mode to which that the adapter is set. Every printer type uses different inks and prints at particular resolutions.

    In addition, the human eye may perceive the same colors differently on different devices. For instance, when colors are produced by computer monitors, they appear different than they would if they were produced on a printing press. A correction factor, called gamma correction, is used to compensate for such perceived differences.

    The result of these device-dependent factors is that each color device has a particular set of colors that it can produce. This color set is known as its gamut. To perform color conversion and color mapping, the colors in an image must be converted from the color space and gamut of the source device into the color space of the destination device. They are then matched into the gamut of the destination device."


    You may find that your printer allows you to try and match its output to what you see on screen, which I suspect might prove a lot easier!
    FWIW.
    Regards,
    Rory

    Microsoft MVP - Excel

  3. #3
    Platinum Lounger
    Join Date
    Feb 2002
    Location
    A Magic Forest in Deepest, Darkest Kent
    Posts
    5,681
    Thanks
    0
    Thanked 1 Time in 1 Post

    Re: RGB v CMYK (Excel 97 SR2)

    Hi there
    thanks for the info, it looks an absolute nightmare <img src=/S/brainwash.gif border=0 alt=brainwash width=15 height=15>.
    We have had a fiddle with the printer set up now and found we can get the printer to do the conversions for us at it has built in colour management pallettes. Phew!

    Jezza
    Jerry

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •