How to see colors on my Mac the way a PC user sees them

I doubt you could ever truly match colors between computers if only because the monitors are not likely the same nor are the video cards.

There are tables of so-called web-compatible colors. If you open the OS X color selector and choose the Color Palettes icon in the toolbar, then select the Web Safe Colors from the drop down menu. You can access the selector from within the Appearance preference pane.

If you have the proper .icc configuration files installed on each computer, then you can create ICC profiles that can be used to match the colors across different hardware, and of course there's ColorSync but it's not supported on every PC.

This has been an 'issue' for decades. Windows uses different gamma than Macs. Always have. Graphics designers have always had to remember that Windows users are intentionally crippled in the graphics dept. (IMHO).

When Mac designers are sending their finals to Mac printing houses, everything is fine.

What I would suggest trying is to make a new Color Profile with a 2.2 gamma and test the images you make then on the PCs. That has been the usual answer for Mac-heads that are forced to design for Windows (poor things).

That way you can switch Profiles for making Windows-compatible graphics that will render better.

Keep in mind that the colors will NEVER match 100% between macs and PCs. But at least you won't be guessing...

Yes, I understand. But I think you may find it a difficult problem to overcome because of monitor differences. I've seen this just between the LCD display on my MacBook Pro and my Mac Pro. The latter drives a Viewsonic monitor and certain colors render quite differently on the two monitors. It's not a Colorsync problem nor an ICC profile problem, it appears to be a monitor problem. I have a couple of friends who have reported similar color differences.

The native Gamma for Macs is supposedly 1.8, but for PCs it's supposed to be 2.0 or 2.2 (not sure which.) Different white point settings can also cause differences in color and brightness.

You could alter the color calibration of your monitor by using the Calibrate option in the Displays preference. I suspect, however, that even if you get the images to display the way you want on one PC they may not display that way on another.

In Windows, the default gamma is a much darker 2.2 with a bright bluish white point of 6500K. Change your Mac's display profile to match those settings and the images you create under those settings should look much closer to how you see them on your Mac in Windows.

Profiles are very important in RGB. They let color management software (Kodak in Windows, ColorSync in the Mac OS) know what to do with the image when you open it. That is, when the source and destination profiles don't match (both the monitor and image profiles), the software knows how to alter the image values so the picture looks close to the same on one computer as another. With no profiles embedded, the color management software can't determine the original color spaces. As such, how the images will display on any given monitor will vary slightly, or a lot. It all depends on how that monitor is set up. But this pertains more to color then overall contrast, though it does affect both.

Some (not all) web browsers are aware of profiles. Safari is one. So even if your files have a gamma of 2.2, and a person visiting your web site has their monitor set to a 1.8 gamma, Safari can adjust the color of the images on the fly to have them view correctly by knowing the difference between the embedded image profiles and the user's monitor settings. It's not perfect, but works pretty well.