Converting illustrator ads to grayscale

Question

Some of our ads that have images and gradients in them are printing horribly in newsprint and coming out dark and apparently in cmyk--Which look awful. The only way I can see to turn the ads to grayscale in illustrator is by exporting to jpg. Is there another way. There are images and gradients in these ads. Our preferred format would be in PDF. Any suggestions for creating good grayscale ads in illustrator that has gradients and images and saving to PDF

Answer 1

> Some of our ads that have images and gradients in them are printing horribly in newsprint and coming out dark and apparently in cmyk--Which look awful.
[Don't know what "and apparently in cmyk" means.]
There is no one-size-fits-all colorimetric/automatic "best" conversion from CMYK to grayscale, because software doesn't know what terms like "horribly" and "awful" mean.
You say "our ads", but you don't state who you are, the newspaper receiving the CMYK ads, or the creator of the CMYK ads. The following assumes you are the creator of the ads, and therefore have time and professional interest (and appropriate fees) to do it right.
Especially in a low-res, low-fidelity medium like newsprint, leaving the conversion from color to grayscale up to some "magic formula" is worse than the practice of placing RGB images in a document destined for offset-press and then entrusting the converstion to CMYK to automation.
A CMYK-to-Grayscale conversion table--no matter how numerically accurate and consistent--doesn't know text from sky, or red flower from green leaf. So the optimum conversion from color to grayscale depends highly upon the content and intent of each image. And if I read your post correctly, you said your ads have multiple images, not just one. If so, the conversion shouldn't happen at the whole-document level, either.
For example: Fully saturated red and fully saturated green have similar luminosity. So they both convert to similar grayscale values. That utterly kills any visual contrast between flower petal and leaf, and you end up with an unattractive, flat, and dead-uninteresting midtone blob. It shouldn't take much imagination to think of countless other examples of just-as-bad situations. Imaging an ad for a red car parked in front of a green hedge. Or an add with yellow text in front of a blue sky.
Even when working in Photoshop, conversion to grayscale is seldom best achieved by simply changing the mode from RGB or CMYK to Grayscale. Depending upon the image; depending upon what's
important in the image, a far better conversion is often the use of the green channel, instead of the L. Sometimes blending two or more channels results in a better grayscale conversion. And a curves adjustment is almost always called for.
So to answer your question correctly, one would have to see a specific example--or one would have to say build the grayscale ads correctly
for grayscale newsprint reproduction in the first place, so you can see the value contrast (because that's the only kind of contrast you will get in grayscale) before you actually go to press.
JET