My eyes aren't as sharp as they used to be so I found the small fonts used in the N900 to be less than ideal. I searched for a way to increase them so that I can read them without wearing my reading glasses. The full credit for these techniques goes to b666m and Grant, I just compiled their info into a step-by-step form for us non-programmers. Thanks guys, now I can read them w/o glasses!

Basically the system fonts can be changed by editing the config file "gtkrc" for the theme you want to use. Each theme has it's own gtkrc file so if you want to switch between themes you have to edit them all.

The font sizes used in the SMS and IM conversations and in the single SMS view are controlled by 3 separate config files with a .css extension. You only need to do this once unlike in the above for themes.

To begin: first, you need to have access to the root. Download the file rootsh from Maemo.extras and install it. Also download and install the text editor Leafpad or you may use another text editor if you wish.

I will be using the theme 'marina' in this example, use whatever theme you want to modify, the steps are the same. So here is how I did it: Please type exactly as shown, as it is case-sensitive. Press 'Enter' after each command.

Part 1: Changing the theme fonts size
1. Open X-terminal
2. Type "sudo gainroot". If you had installed the rootsh mentioned above this will allow you to edit files
3. Type "cd /usr/share/themes"
4. Type "ls" to display the installed themes. This step is optional
5. Type "cd marina/gtk-2.0"
6. type "leafpad gtkrc" to edit the config file gtkrc
7. scroll down or use the search function until you see the section
**********************
*
* font definitions
*
**********************
8. Here you will see the fonts used in this theme. Just increase all fonts below 20 by 2 or 3 points higher.
Example I changed small fonts from 13 to 16
9. Do the same for the section
**************************
*
* new fonts for fremantle
*
**************************
10. When finished, use the pull-down menu to save or just press "x"
to exit. The program will prompt you if you want to save first before exiting

Part 2: Changing the SMS/IM conversation and single SMS font size
11. Type "cd /usr/share/rtcom-messaging-ui/html"
12. type "ls *.css" to see the 3 files you need to edit
13. type "leafpad MessagingWidgetsSMSConversation.css". This will load for editing the config file that controls the size of the fonts we see in the SMS conversation screen
14. Locate the section "div.message {". This is close to the top of the file
15. Place the blinking cursor after the "{" then press <enter> to insert a blank line under "div.message {"
16. type "font-size: 30px;" (without the quotation marks of course)
17. press <enter> again to create another blank line below (optional)
18. I used 30px (pixels) in my case but you can use any size. The size of the avatar is 64 pixels so 32 pixels is half height
19. Save the edited file by using the pull-down save command then "x" to exit after saving
20. Type "leafpad MessagingWidgetsChatConversation.css".
21. Repeat steps 14 to 19
22. Type "leafpad MessagingWidgetsSingleSMS.css"
23. Repeat steps 14 to 19 except for single SMS I used 32px instead of 30px for greater visibility
24. Done. Exit leafpad, exit X-terminal then reboot and enjoy the bigger fonts

This is how I did it. I cannot guarantee that it will work for you and of course I cannot be liable for any damages that may or may not happen to your phone. In my case it worked without a hitch and as you can see in the photos below, the fonts are much easier on the eyes!

Good Luck! If you want to modify another theme then just do Part 1 only. Part 2 is done one time only. It would also be a good idea to make back-up copies of the files before you modify them so in case something goes wrong you can restore.

My apologies for the poor quality pics and for the long post, I intended this post for non-expert people like myself who only wish to have bigger fonts the better to enjoy the N900. Oh I love my N900, what other phone allows me to tweak config files like this?

Thanks a lot for this post.. have been looking everywhere and probably must have spoiled my eyes. Appreciate it. Very well put

This is one of the best tips I've seen around here. Finally I don't need to press my nose against the screen to read what's there! Thanks a bunch.

Great post! I wish Nokia would add an option for this in settings...

I followed the steps and everything works fine

Great post, but nothing changed on my screen Followed your instructions exactly (for marina) but no increase on font size. Reading glasses are not always handy and I am especially interested if your solution given larger fonts on selecting contacts in phone application. Any more suggestions?

Did you reboot afterwards? That might be necessary. Also you have to use the Marina theme, since that's the one you edited.

Excellent. thank you.
Has anyone else noticed that sometimes the font size increases randomly on all windows? this only lasts a few seconds and then goes back to normal.

Just a suggestion, and I'm sorry I haven't the time to describe how, but it would be a great idea to copy the theme first, adjust for large fonts/hard of seeing, then send to the theme creators to publish them alongside the originals... perhaps it could even be a standard thing... then the standard user can easily choose a "large font" version of any theme.
It's not a lot of extra work for the theme designers really, and give them an additional market that might consist of people who don't care too much about the theme itself, but do want their phone to be easily readable..

Yes, I did. SMS and conversations fonts are increased, but not theme fonts

EDIT: Increased all fonts by approx %25 bigger size. Works perfect. Thanks all.

Thanks for this. You might like to use Ctrl+Shift+P to take screenshots, rather than using a camera.

A wonder if it is possible to make an app to do this?