# Why is \topfraction larger than \bottomfraction?

Somebody I worked with told me that he does not like to have floats “here” (`[h]`) but only at “top”, “bottom”, or “page” (`[tbp]`). After using this for my own documents for a while, I quite like it; the “here” floats often are stumbing blocks for the reading flow.

The thing with figures in the “top” placement is that their caption (below the image) and the body text looks very alike, I have the same font and the `scrreprt` `caption` by default indents additional lines. I thought that it might be a good idea to restrict float placement to `bp`. Then the figure would not be a stumbling block within the text but the reader can also continue reading the body text at the beginning of the new page instead of finding the end of the caption first.

Noticing that all slightly larger floats end up on separate pages now, I found that `\topfraction` is way larger than `\bottomfraction`. It seems the authors of those default values have had some reason do chose them like this. Usually the defaults lead to visually pleasing results, so I wonder what the background is here.

• Why are large floats at the bottom of a page discouraged by default?
• Would I do the reader a favor by setting `\bottomfraction` to the value `\topfraction` has and using `[bp]` as a float placement?

Either the "turn of a page" or the "gutter" provides a physical break between the text and the float when they are at the top of the page. In my opinion, this prepares the reader better for the possibility of the discontinuity being interrupted by something like a float since the break could happen mid-paragraph.

Placing a float at the `[b]`ottom of the page may leave the reader jumping to the caption as part of the textual flow if there is no visual distinction between the paragraph and caption text (something like Figure X.Y: in bold or a different font/colour for the caption)*.

This might be a (somewhat speculative) argument for discouraging floats at the bottom of a page in general. Setting `\bottomfraction` to be the same as `\topfraction` may also be in favour of placing content at the `[b]`ottom, may have little effect if precedence is given to placing floats at the `[t]`op. But then again, this depends heavily on the document layout.

*The same goes for `[h]`ere (which in some ways are similar to `[b]`ottom) unless there is a visual queue for the break, like a paragraph separation.

One general remark on the `h`ere placemnt: A figure can only be next to a reference to it when there is only a single reference to the figure in the text. If there is a second, maybe just one sentence below, the figure might still be close. This works well for things like "...see the following example".

However, if you refer to a figure, or maybe to parts of a figure, more than once or twice, there is no proper "here". Thus, one puts the figure to the top (or bottom) of a page. Then, at least as you are on the same page, you can read the text without any breaks and easily find the figure the text refers to. This, I think, works for top and bottom placement.

However, if your text that discusses the figure spans more than one page you will have to turn pages. Of course, readers are used to start reading at the top of a page, this is why I think that top placement is preferable: After turning the page, you will first look at the top and you will find the figure you are looking for. Even if you turn the pages backwards.

Of course, this requires an easy-to-recognize optical difference between caption and text. And this is not true for all publishing formats. While it's fine for anything on paper, if I read a pdf on the screen, I have to scroll over the entire text of the previous page to find the figure. Here, bottom placement seems to be better.