user3219: The program becomes harder to read (at least on my particular monitor) after upgrading. 
Any way to change font Color to darker color and/or Type to thicker stroke (like B in this question editor) for IDE 1.5.6r2?

user60: Yes.
Under the file menu select the preferences. From this you can find and than view/edit the preferences.txt file, which has the color settings.
Example preferences.txt

3219: <p>The program becomes harder to read (at least on my particular monitor) after upgrading. </p>

<p>Any way to change font <strong>Color to darker</strong> color and/or <strong>Type to thicker stroke</strong> (like B in this question editor) for IDE 1.5.6r2?</p>
 60: <p>Yes.</p>

<p>Under the file menu select the preferences. From this you can find and than view/edit the preferences.txt file, which has the color settings.</p>

<p>Example <a href="https://github.com/arduino/Arduino/blob/master/build/shared/lib/preferences.txt" rel="nofollow noreferrer">preferences.txt</a></p>
