iMac G3, CRT monitor doesn't show dark colors well - dark clors appear black

[StevenBram]

I can barely see digital pictures and the likes. But websites and such i can see fine so long as the colors are light and looking on this site... http://www.momentskept.com/MonitorCalibration.htm

the first image i absolutely cannot see, it is 100% pitch black.. the other bellow it shows up just fine. But the two left/lowest squares on the color table on the very bottom the page both appear the same shade of pitch black.

I can see light but not dark. I tried callibrating and adjusting brightness and contrast.

 

[DeltaMac]

I work at a school system which has hundreds of those iMac models. I see dim displays quite often.
Unfortunately, your CRT is getting old...
An older CRT will lose brightness over time, some will age faster than others. The only fix is to replace the CRT, or maybe the video board. On an iMac with a Slot-loading CD drive, (and not an older model with a tray-type drive) that board has the power supply, and the high voltage video drive (it's called a PAV). One of those (or both PAV and CRT) will fix the brightness. I doubt that you will find good replacement parts for a reasonable cost now. Easier to find a used complete iMac like yours that still has good parts - then swap your hard drive into that better iMac.
There is an internal adjustment for brightness on the same assembly where you can adjust the video focus - but that may not help, or will make the whole screen very washed out, or won't last very long until you need to adjust again.

 

[icemanjc]

I work at a school system which has hundreds of those iMac models. I see dim displays quite often.

Same with ours, that's the reason as to why we tossed many of the earlier iMacs we had.

And actually hitting the iMac was actually a temporary fix for the screen and it'd stay fine for about an hour.