Page bottoms not lining up

Just a quick comment on lining up text on the bottom of pages for say a 200 page novel. You will need a Paragraph Style for a Sub-Heading that is at the top of a page, and a Paragraph Style for a Sub-Heading that is not at the top of a page. 

 See above: Text lines up at bottom of page for Sub-heading not at the top of a page

For a Sub-Heading that is not at the top of a page, Set your "Paragraph Style Options" >> Space before and >> Space After for your headings to equal the multiples of the leading for your font. Example, if your leading for your font is 16pt; then use 16pt, 32pt, etc your heading. Works great. All text lines up at the bottom of the page. See below for set up in Paragraph Styles (Heading 3 is my Sub-heading not at the top of a page). 

If your Sub-heading is at the top of a page, you need another Paragraph Style to handle this. 

 See above: Text lines up at bottom of pages with Sub-heading at top of page.

Below is how I got it to work even though I don't understand mathematically how it works (Paragraph Style is called "Top page heading".

The Space Before and Space After do not add up to a multiple of 16 (like with headings not at the top of pages. But the above works for the whole book. 

Hope this helps someone.

Using the baseline grid is the "hard" or forced way to maintain even line and page spacing. What lies beneath it, sort of, is understanding how to give your set of paragraph styles harmonious line and other spacing, relative to the page's margin height, so that pretty much no matter what combination you use on any page (or in any column), the last line falls right at the bottom page margin. It's a learned art.

The takeaway here is that just turning on baseline grid might produce unwanted spacing results; it helps if you understand what it's trying to do and work with it. Adjust your styles' spacing with and without it, until there's no visible difference on most pages.

It can be related to the values you have used for leading, paragraph before/after spacing, and paragraph rule weight, and possibly more. Everything should line up at the bottom if the values are uniform, like leading is 12 points, paragraph spacing is 12 pt, etc. so that by the time the column hits the bottom of the text frame, the last lines end at the same vertical position. But what happens more often is after the variety of values used for leading, spacing, and rules are totaled for each column, the last lines can’t possibly align.

For example, if the left column has three paragraphs and the right column has two, and the paragraph Space Before value is 6 points, then the left column had 12 pt of total paragraph spacing and the right column has 18 pts, and if the leading is for example 4 pts, then after the spacing is totaled for each column, there is a very low chance that the last lines of the two columns will fall exactly at the same vertical position. The total spacing of the left column from its combination of leading, paragraph spacing, rules, etc. might add up to for example 624 points (just making up example values here), and the total in the right column might add up to 618 points.

One way to solve this is Will Adelberger’s suggestion of establishing a baseline grid and forcing all lines to align to it. Another way is to choose Object > Text Frame Options, and set Vertical Justification to Justify, which forces the top and bottom lines of columns to align by distributing their lines evenly from top to bottom.

Both of those solutions override whatever your spacing values are, because that’s the only way to force all lines to stick to a grid or line up at both the top and bottom. If you don’t want that to happen, then you must choose a combination of leading/spacing/rule weight values that mathematically line up every time. 

The disadvantage of vertical justification is that it only looks perfect if all columns have the same number of lines. Because if the left column as 10 lines and the right column has 11, then although they will align at top and bottom, they will have different spacing because across the same distance, there has to be more space between each of 10 lines than each of 11 lines.

Also be aware that other options can make it more difficult. For example, two columns might have enough lines of text to fill both columns equally, but the last paragraph in the left column only shows its first line in the first column and in its Keep options, Keep Lines Together is enabled with Start 2 Lines. To keep the first two lines together, the paragraph would be forced to start in the next column, leaving the left column short a couple lines compared to the right column.

So getting columns to always line up exactly at the bottom requires thinking through all these combinations of values and options, because it’s so easy to set up a combination that technically can’t work because of just one setting.

Use a baseline grid alignment. Make the width of the bottom border so, that it align with the baseline grid.