Expert: Amy - 5/12/2009

Question
Hi do know how blend 2 spot colours without it going into CMYK

Answer
Hi Keith,

To make a gradient from two spot colors, the method you use depends on the particular colors and what file format you are giving your printer, somewhat.

Before CS2, I believe, Illustrator used CMYK colors between the spots. This was a problem. With CS2 and later, you can just create your gradient using colors from your Pantone color book swatches. Although I cannot say for sure, I think that as long as you or your printer adjusts the angles of your spot colors, your gradients should come out nicely. When in doubt, call the printer and ask. I find that they generally enjoy having well-informed customers.

To create gradients with spot colors, open the spot color swatch book window, the color window, and the gradient window. Create spot gradients by dragging spot colors onto the Gradient Slider bars. You can also drag spot colors over from your swatch window. If you need to adjust the tint of a spot color used in your gradient, just click on the gradient slider bar that uses that spot and adjust its tint in the color window. That is all you have to do. Then drag your gradient onto the object you want to fill.

I will tell you the other method you can use, just in case you are curious how it was done a few years ago. Instead of creating one gradient that goes from spot color A to spot color B, you can make gradients by layering two gradients.

First fill the object with a gradient of 100% to 0% of the lighter spot color. Then duplicate the object and fill it with a gradient of 100% to 0% of the darker spot color. Set the top object's blending mode to multiply. Make sure to turn on your View > Overprint preview to see the results.

No matter which method you use, overlapping spots need to have different screen angles when you print or you will get a moire pattern on your product. The angles will be set to 45 degrees to start. To change this, choose print, select AdobePDF or a postscript printer, then choose output, then change the mode to separations. Talk to your printer about what angles to use or ask them to set the angles for you to eliminate any moire that might occur.

Good luck!
Amy Pace