Line width in inported graphics slightly diminishing in FM generated PDFs

[Steve Rickaby]

At 09:52 +0900 8/3/06, Yosuke Ichikawa wrote:

>We're using Acrobat's preflight feature to check for lines thinner than
>0.2 pts. The thinnest lines in our .eps graphics are exactly 0.2 pts,
>but when we import these graphics in FM and check the PDFs created from
>FM, Acrobat preflight says the graphics uses "0.199600pt" lines.
>
>PDFs of these individual graphics, created from Illustrator, do not
>have problems with Acrobat prefight, so it seems to be some sort of FM
>conversion problem.
>
>Why does this happen, and is there any way to prevent this on the FM
>side? If there is no way to fix this, we'd have to tell our illustrator
>to make the lines in the graphics slightly thicker.

This looks a lot like a rounding error problem due to two different applications using different precision math. In floating-point math, computers use a set number of bits to represent the complete range of natural numbers. As a result, some numbers actually cannot be represented precisely: the more bits you use, the closer you get, but there's always a compromise.

I guess you have two approaches:

. Ignore the preflighting and print anyway

. Make the lines a little thicker
-- 
Steve