Gradient Problems with colours

Question

Hi I am new to Illustrator (just bought CS5) and I am having trouble with the colours when using gradients (colours are generally duller as well) but when I make a gradient from red to black the computer automatically puts a grey inbetween, (photoshop has no problems the colours are clear and bright)  I recently did a tutorial http://veerle.duoh.com/design/article/illustrator_inset_effect_on_text_in_combination_with _clipping_mask (she had the same tutorial in photoshop, which worked great) but my colours in illustrator are having this grey issue and the image came out looking very dull. 
Is there some file setting I may have changed to cause this?
Thank you

Answer 1

The color setup in AI is trying to simulate the way CMYK actually looks in print. Sometimes the simulated display goes overboard, and it's impractical to write you a textbook on the whole color management (color calibration) subject in a user forum. (Plus, replies in a user forum are as often wrong as right.) There is plenty of reading material out there for you on this. (Start with the Help files, as the Color Settings dialog suggests.)
When designing for CMYK print, work in a CMYK document. Switching color modes is bad practice, especially if you intend for your on-press values to actually be the values you specify in the document. For example:
1. Set up your red (100M, 100Y) to black (100K) grad.
2. Change Document Color Mode to RGB.
3. Change Document Color Mode to CMYK.
4. Look at what has happened to your original CMYK values.
The best way to work in CMYK is to have a basic understanding of CMYK and the real-world principles of process printing. For example, if you do as Jacob suggests, and make the black end of your grad also contain the "red" (100M, 100Y), you will have a 300% total ink coverage at that end of your grad. That may or may not be a problem, depending on the target printing environment.
Generally speaking, yes; CMYK print is almost always "dull" compared to viewing RGB on a monitor (and you are always viewing RGB on a monitor, even if it is shifted to simulate CMYK). This is true regardless of color calibration. Common sense goes a long way. Monitors glow; paper doesn't.
One of the most overlooked facts is that human vision is highly adaptive. Even in RGB, your monitor never displays anything even approaching a true black. Yet your eye nonetheless sees a dark rich black.
CMYK process, for example, is very poor at reproducing brilliant blues. Yet the combination of knowledgeable image color correction (as opposed to mere calibration), quality printing, and the adaptive nature of human vision can nonetheless result in printed blues that seem to "glow."
If you're designing for commercial print, you should seek to understand the process enough that you would be comfortable assigning colors while working on a grayscale monitor. Again, that comes from both study and real-world exposure. Actually visit the press room whenever you have the opportunity. Maybe even take a course in commercial repro at the local tech school. You can't really gain the understanding you need in a software user forum. This is a huge subject.
JET