I wonder if there is a tool to control gamma on crt monitors that works for DOS.
See on windows98 for example you are given control over the gamma, you can change RED , GREEN AND BLUE manually.

I think my monitor is so old that has its issues.
For example the monitor built in menu only gives me "Color temperature":
Variable + 5000K + 9000K, one is too warm, the other one is very blueish.

anyway my problem is that depending on brightness and contrast settings that i choose, the screen shows a REDISH like black color. more like a a black mixed with red wine. If i increase the contrast to 85% and keep brightness level to 70% aprox, the redish color on black dissapears a lot.

but that redish should not happen for example on good crt monitors, if you increase the brightness and constrast you actually see grey or black or white. But in this case increasing the brightness and contrast looks good and if you lower it .. the blacks start to look black-redish.

On other colors the screen just looks perfect, for example win98 the screen looks with all colors nicely, including red, but i noticed it on DOS command prompt, because the background is black.