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? What is the difference between RGB and CMYK colour?
 

RGB (Red, Green, Blue) colour is what is refered to as Additive colour, while CMYK (Cyan, Magenta, Yellow, blacK) is Subtractive color

                           

          RGB Colour                CMYK Colour

Computer monitors display colour as RGB light. Although all colours of the visible spectrum can be produced by merging red, green and blue light, monitors are capable of displaying only a limited gamut (or range) of the visible light spectrum.

Whereas monitors emit light, inked paper absorbs or reflects specific wavelengths. Cyan, magenta and yellow pigments serve as filters, subtracting varying degrees of red, green and blue from white light to produce a selective gamut of colour. In theory, CMY should be sufficient to reproduce the colours, but due to the physics of ink on paper, and reflected light, when the three colours are mixed, it forms a grayish-brown colour, so black ink is added to compensate. Like monitors, printing inks also produce a colour gamut that is only a portion of the visible spectrum, although the range is not the same for both. Because of this, the same art displayed on a computer monitor may not match to that printed in a publication. Also, because printing processes such as offset lithography use CMYK inks, files must be converted to CMYK colour for print.

The image below shows the difference in gamut (the amount of colour that can be reproduced) for visible light, RGB Monitors, and Offset printing.  You will notice that the gamut decreases as you move from visible light, to monitors, to presses.  This is why colours which are printed do not always match what you see on the screen, if they are outside the physical boundaries of the gamut being used.

As you can see, the amount of colour that CMYK printing on newprint provides is extremely reduced when compared to the amount of colour your monitor can reproduce.

Colour management systems, and colour calibration are ways to avoid this problem.  A proper CMS (colour management system) will adjust the image displayed on the monitor to match the physical properties of the CMYK press, so you have fewer surprises.

For more information on colour management systems, click on the CMS link in the FAQs

? What different kinds of paper do you use?
 

We normally stock 3 different types of paper:

A 30 lb standard newsprint,

A 35 lb high-bright (80 brightness) premium newsprint,

and a 50 lb bookstock.

? What type of software can I use?
 

We can accept almost any type of file, and we are cross-platform, which means that we accept both MAC and Windows files.

This includes native CorelDraw, QuarkXpress, PageMaker, InDesign, Illustrator, Photoshop, Acrobat (PDF), as well as MS Word, and MS Publisher files.

We prefer PDF files, however these can cause more problems than a native file if they are not prepared correctly. (see the next FAQ for instructions on how to properly create a PDF file).

If you have any questions about your files, or how to prepare them, please contact our prepress department, and one of our staff will be happy to assist you.

email: prepress@wellerpublishing.com

 

? How do I prepare a proper PDF file?
 

PDF files may now be created natively with most layout or desktop publishing software.

PDF stands for Portable Document Format.  The original (and most will say the best) PDF file format was developed by  Adobe Systems.

PDF standards and technology are derived from the original code developed by Adobe.

MOST types of DTP (DeskTop Publishing) software now support PDF creation.

The best (and usually safest) way to create a PDF file is using the Adobe Acrobat, and Adobe Distiller software.

When installed, Acrobat creates a virtual printer, and installs Distiller, which can be used to make an almost foolproof PDF file.

For instructions on how to use Adobe Acrobat or Adobe Distiller to create PROPER pdf files for print, download the PDF file (oddly enough) from this link:

In order to view this or other PDF files, you must have at Acrobat Reader installed for Windows PC's prior to Vista, or Mac OS lower than OS-X.

Mac OS-X and Windows Vista, or newer natively support displaying PDF files

 Acrobat reader may be downloaded from this link:

                                                        

Microsoft Office has an add-in available which will allow you to save your document (from any office application) as a PDF file.

It can be found at this link: http://www.microsoft.com/downloads/details.aspx?FamilyId=F1FC413C-6D89-4F15-991B-63B07BA5F2E5&displaylang=en   Once there, click the DOWNLOAD button, and follow the instructions.

 

? What is CMS?
 

CMS stands for Colour Management System.

This is method by which every device in a workflow, i.e. scanners, cameras, monitors, proofers, and printing presses are all profiled, and these profiles are used in the workflow to achieve accurate, and matched colour reproduction on all devices in the system.

Profiling means that a device is measured as to how much of a known colour range is reproduced, and that information is saved in a file known as a colour profile, or a device profile.

Once a device has been profiled, it can be calibrated so that it remains to the standards set by the profile.

As mentioned in the What is the difference between RGB and CMYK? FAQ, colour is represented by it's Gamut, or range of reproducible colour for a specific device.

Every colour in the visible light spectrum can be represented numerically, or mathematically using CIE L*a*b* colours

 

CMS adjusts the colour data of a file using the profiles created for the devices in the workflow, usually working backwards from the finished product.

For example:

For an accurate display on your monitor, or proofer, the CMS uses the profile from the printing press, and changes the spectral data (the numerical values the computer used to create the image) to match what the printing press is capable of reproducing.

 

? Do you have any useful, or otherwise cool links?
 

Welcome to the links page.

       file_library/userfiles/latest iphone 296(2).jpg

Here we have a collection of useful, informative, or otherwise cool links for our visitors.

We are continually updating them, and do welcome submissions from you.

www.gain.net     www.quark.com    www.adobe.com   www.microsoft.com/office  

  • How to make a printer's hat: click HERE (this is what printers used to wear to keep ink out of their hair)
  • Vocational film from the 1940's showing how printing was done: click HERE
  • Vocational film from the 1960's showing how typesetting was done:
    click HERE for part 1, click HERE for part 2
  • Vocational film about bookbinding from the 1960's click HERE
  • Start to finish of a newspaper story to final printing circa 1950 click HERE 
  • Click HERE to see how the Chicago Tribune used to do things
  • Click HERE to see how photos used to be sent across the telephone
  • Glossary of printing terms (online soon)

If you have a link you think we should take a look at, just email it to us:

coolstuff@wellerpublishing.com

 


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