Kerem,

You've got essentially no control over how your images look on other monitors. Ignoring the issue of color drift, keep in mind that the shape of pixels is not even the same between one resolution and the next on the same monitor, let alone across different monitors.

It sounds like, rather than calibrating your monitor, you are using pre-packaged, company-supplied profiles. Consider that these numbers have nothing to do with how your monitor emits color, or what environment they emit color in.

Without calibrating your monitor in a room light as you always light your monitor, there is no way to guarantee color consistency. You need to calibrate your monitor based on the specific conditions of your editing environment before any reasonable attempt can be made to solve any other problem. You monitor probably has a manual system for doing this, where you make adjustments until you can distinguish between one box of color and an adjacent one, or the like. This option, while not optimal, would be a significant improvement over the choice you are making now.

Adobe 1998 is a theoretical color model. sRGB is another one. They are the two most popular ones in use today, with sRGB being the default assumption about images that do not include a color profile. They are an abstract set of definitions regarding how to distinguish between one color and another. The advantage to using either one is only realized if you include it in the file itself (thereby telling other computers how to render each color on the specific monitor they are attached to).

An image file is essentially a collection of numbers, describing each pixel of color. When a profile is attached to an image (or, when sRGB is assumed because you haven't included one), the program opening it knows how to relate the color information in the file to the way the attached monitor displays these colors. If the monitor has not been calibrated, it will display these colors incorrectly. In your case, the problem is that our computers begin with an incorrect assumption: we think you're editing in sRGB, when you're actually editing in a color model that no one but you knows.

Most professionals use Adobe 1998 as a working color profile, under the assumption that their image will be printed at some point. If your images are only going to be seen on a monitor, then sRGB is fine. If your images are only going to be seen on your own (regularly calibrated) monitor, then this is the only time when using Monitor Profile is an appropriate choice.

As you may have guessed by now, I'm a huge advocate of color calibration, and I've probably spent quite enough time on that soap box for now. If you're interested in learning more, I can go into greater detail. But for now, let me step off the soap box and answer your question directly:

In order to get fewer people complaining that your images are too dark, then I suggest you start working in the sRGB or Adobe 1998 profile. Next, you must calibrate your monitor, either using a third-party strategy, or the inexact option built into your monitor's menus. You need to recalibrate your monitor, at an absolute minimum, once every three months (I know people who calibrate their monitors weekly, and some who do it even more often than that). Finally, when saving your images for web display, you must NOT optimize them for web output, and be sure to include your profile in the saved file.

If you do this, then if people still complain that your image is too dark, you can tell them that they need to calibrate their monitor.

They had chained him down to things that are, and had then explained the workings of those things till mystery had gone out of the world....And when he had failed to find [wonder and mystery] in things whose laws are known and measurable, they told him he lacked imagination, and was immature because he preferred dream-illusions to the illusions of our physical creation.
      -- HP Lovecraft, The Silver Key