Adobe Illustrator TIP:
Sometimes, you can print a color to film and find that it is coming out in halftones.
There are many reason why this can happen. Here are a few common ones.
First know that there are two areas of a color that can be adjusted for output that pertain to opacity and therefore, create halftones. One is in the COLOR, and the other is in the TRANSPARENCY.
To print solid custom spot colors, the COLOR is set to 100% solidity. Once it is decreased in solidity at any amount, it creates halftones of that color to represent lighter shades.
Another area where this can happen is in “Transparency” If the opacity of the object or “type” is not 100%, it will come out in halftones. It can be 100% solid in the color, but the transparency can still be set lower than 100% or the opposite is true as well. Both of these areas create halftones in what can look like solid filled elements. If you are receiving art from a customer, you should check these areas to know for sure, by selecting the item in question, and check each of these areas. Sometimes, a grouped element may contain multiple sub layers of elements and those within the main group (could have the opacity or the color turned down)...and you would not knowby looking at the main grouped selection as that will tell you that “the group”is 100% solid while items within are not. You would not know for sure, unless you print your separations or if you were to break the grouped element apart and select each item and confirm it’s solidity.
It may help to know the differences also between a COLOR solidity and an items Transparency. Why do we have two different areas of percentages of color that create halftones?
The main difference between the two, is that reducing COLOR opacity, introduces computer white aka (computer/cmyk/rgb/default white), to the content of the item...and is opaque. In other words, during the separation process when you print to film, the white portion of that percentage will knock out any color behind it (since (computer/cmyk/rgb/default white), is NOT a real printing color). When you put a custom color - under that item that has color solidity turned down, the (computer/cmyk/rgb/default white) that is in it will knock out of the other colors below it. For this reason, a lot of people put the base white down under all of the spot color art in the layer stack, so that the spot colors can overprint the base white...and you can stroke or choke the base with a computer white that does not affect the top colors (because it is placed down under the top color).
Transparency on the other hand, does not introduce white of any kind. Both of these options are used for different purposes in design.
Computer/cmyk/rgb/default white, is not to be confused with a CUSTOM color, SPOT white. A custom color spot white can print as a separation of color, while with the (computer/cmyk/rgb/default white), nothing comes out. It’s a non printing white.
