Is there any method of adjusting kerning overall in either Inkscape, Photoshop, fontforge, Illustrator, etc.? I have designed a font but the kerning on EVERY letter is too big. I know I can do some kerning pairs but I doubt I am willing to do the 2704+ different pairs. Is there a way to make the kerning for each letter smaller is my big question. I see plenty of tutorials on how to do it between something like "T" and "a" but none discussing how to adjust it in general. I have access to Photoshop, Inkscape, fontforge and Illustrator if need be but not other font-specific programs other than fontforge. I don't want to purchase any software so open source will do.

I have a Windows OS but I run mostly on a Linux OS. Thus, open source software is always nice.

First thing is to set the advance widths, left and right, for every glyph to get an overall correct letter spacing. then you will need far less kerning pairs.
When done make a document in a word processor or anything else that uses kerning with a text like aa ab ac ad ae af etc. all the way from AA to zz. There you can see which letter combinations need kerning or not.

Best solution, get yourself a font editor that has a auto kerning function. that will take care of some 80% of the work.

I think I got it in fontforge; thanks. It turns out that the values were off by a whole lot so all I needed to do was to modify some numbers to fix it. Now that it works with all letters, I have to focus on T...some of the lowercase letters are too close to capital T. I know how to fix it, though.

Thanks, again.

FYI, overall character-to-character spacing in a font is called "tracking". "Kerning" is an adjustment made to the tracking, on a case-by-case basis for manually defined character pairs.