My coworkers and I have been befuddled by something strange since we switched to CS5 and a new content management system.
Grids we create on seemingly-simple pages end up being off by thousandsths of an inch. For example:
Our pages are 66p0 x 23.5in. Margins are set at 0.75in top and bottom, and 3p4 inside and outside.
This means the dimensions of the working space on the page are 59p4 x 22in.
Because of the way our ad software works, standard columns have to be set at 6 columns with p8 gutters. We make these columns white, so they look invisible on the page.
On an open page without ads, we typically design on a four- or five-column grid. We use the Layout > Create Guides option to make the grid, on a separate locked layer.
If I make a four column grid, the first grid line (left edge of the working space) is at 0p0.004.
The next grid line (right side of col 1) is 11p0.804.
It's like this across the page. The rightmost grid line (right edge of working space) is at 59p4.004.
WHY? It's driving us crazy, yet we can't see any reason why this should be.
For what it's worth, we're working in a Windows 7 environment. Key units/increments prteferences are:
origin: page
horizontal: picas
verical: inches
points/inch: PostScript (72pts/inch)