Newbiw question about dot gain

I'm preparing grayscale art for my publisher and the publisher has given me specifications for halftones as follows: 3% highlight; 90% shadow; 13% midtone. I know how (I think) to set up the 3% and 90% specifications, but how do I set up the 13% specification?

Also, the publisher has specified 18% dot gain. I see only 15% or 20% in the color preference settings for grayscale. How can I specify 18%.

Any help would be much appreciated.

Russ

Oh, I'm using Photoshop 6.0 for Windows.
"Russell Till" wrote in message

I'm preparing grayscale art for my publisher and the publisher has given me specifications for halftones as follows: 3% highlight; 90% shadow; 13% midtone. I know how (I think) to set up the 3% and 90% specifications, but how do I set up the 13% specification?

Also, the publisher has specified 18% dot gain. I see only 15% or 20% in the color preference settings for grayscale. How can I specify 18%.
Any help would be much appreciated.

Russ