printing changes colors?

Hi, I'm not sure whether this question belongs here...but yea, I'm doing a graphic for a box package in Illustrator. The background color is the #333333, with big words in grey using #666666. When I brought the image to a print shop to test it, the colors turned out kinda greyish green. The print file is in CMYK. Any ideas why this happened? and how do I fix it? Thanks

Understanding color between systems, RIP's and ICC's may be difficult, hopefully, a few basics to help,

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Why colors don't match -- No device in a publishing system is capable of reproducing the full range of colors viewable to the human eye. Each device operates within a specific color space, which can produce a certain range, or gamut, of colors.

The RGB (red, green, blue) and CMYK (cyan, magenta, yellow, black) color modes represent two main categories of color spaces. The gamuts of the RGB and CMYK spaces are very different; while the RGB gamut is generally larger (that is, capable of representing more colors) than CMYK, some CMYK colors still fall outside the RGB gamut. (See Color gamuts (Photoshop) for an illustration.) In addition, different devices produce slightly different gamuts within the same color mode. For example, a variety of RGB spaces can exist among scanners and monitors, and a variety of CMYK spaces can exist among printing presses.

Because of these varying color spaces, colors can shift in appearance as you transfer documents between different devices. Color variations can result from different image sources (scanners and software produce art using different color spaces), differences in the way software applications define color, differences in print media (newsprint paper reproduces a smaller gamut than magazine-quality paper), and other natural variations, such as manufacturing differences in monitors or monitor age.
Color numbers

Each pixel in an image document has a set of color numbers that describe the pixel's location in a particular color mode--for example, red, green, and blue values for the RGB mode. However, the actual appearance of the pixel may vary when output or displayed on different devices, because each device has a particular way of translating the raw numbers into visual color. (See Why colors sometimes don't match.) When you apply color and tonal adjustments or convert a document to a different color space, you are changing the document's color numbers.

Color profiles

An ICC workflow uses color profiles to determine how color numbers in a document translate to actual color appearances. A profile systematically describes how color numbers map to a particular color space, usually that of a device such as a scanner, printer, or monitor. By associating, or tagging, a document with a color profile, you provide a definition of actual color appearances in the document; changing the associated profile changes the color appearances. (For information on displaying the current profile name in the status bar, see Displaying file and image information.) Documents without associated profiles are known as untagged and contain only raw color numbers. When working with untagged documents, Photoshop uses the current working space profile to display and edit colors.

Viewing color around you.

View your documents in an environment that provides a consistent light level and color temperature. For example, the color characteristics of sunlight change throughout the day and alter the way colors appear on your screen


Understanding color models
You need a precise method to define colours. Colour models provide various methods to define colours, each model defining colours through the use of specific color components. There are a range of color models to choose from when creating graphics.

CMYK color model
The CMYK color model defines color using the following components:

C Cyan

M Magenta

Y Yellow

K Black


The cyan, magenta, yellow, and black components are the amounts of cyan, magenta, yellow, and black ink that a CMYK color contains and are measured in percent from 0 to 100.

The CMYK color model is a subtractive color model. Subtractive color models use reflected light to display color. Printed materials are produced using the CMYK color model. When you combine cyan, magenta, yellow, and black, so that the value of each component is 100, the result is black. When the value of each component is 0, the result is pure white.

RGB color model
The RGB color model defines color using the following components:

R Red

G Green

B Blue


The red, green, and blue components are the amounts of red, green, and blue light that an RGB color contains and are measured in values ranging from 0 to 255.

The RGB color model is an additive color model. Additive color models use transmitted light to display color. Monitors use the RGB color model. When you add red light, blue light, and green light together, so that the value of each component is 255, the color white displays. When the value of each component is 0, the result is pure black.

HSB color model
The HSB color model defines color using the following components:

H Hue

S Saturation

B Brightness


Hue describes the pigment of a color and is measured in degrees from 0 to 359 (for example, 0 degrees is red, 60 degrees yellow, 120 degrees green, 180 degrees cyan, 240 degrees blue, and 300 degrees magenta). Saturation describes the vividness or dullness of a color and is measured in percent from 0 to 100 (the higher the percentage, the more vivid the color). Brightness describes the amount of white that the color contains and is measured in percent from 0 to 100 (the higher the percentage, the brighter the color).

Grayscale color model
The Grayscale color model defines color using only one component, lightness, and is measured in values ranging from 0 to 255. Each Grayscale color has equal values of the red, green, and blue components of the RGB color model

thanks