Hi just looking for a recommendation for standard gutter width for a 2 column layout on an A4 page. The point size is 10pt the margins are 12.7mm (the default InDesign setting) I thought this would be easy to google but apparently not I guess its too specific a question
The purpose of the gutter is to separate the text enough that the reader's eye won't accidentally jump from one column to the next. This requires that the gutter width should be set to a value that is at least equal to the point size of the text, preferably equal to or greater than the leading. Anything less, and you'll need a vertical rule to achieve enough visual separation.
This isn't a hard and fast rule, but it's a good starting point and is worth sticking to unless you're trying to create a specific "look" in the layout.
Actually, it will depends of font size, leading, even font color. When you will put your content just try to have a feeling that columns is not struggle with each other, but looks organic and in harmony. And experiment a bit with a gutter to get the best feeling.