Is there any way to change the speckly black background of this screen photo to solid black?
This is a photo of a rectangular selection of a black screen that appears when a computer is booting. To the eye this screen has only three colors. OK is bright green, the other text is white and the background is black, however in this screen photo the background is mottled black and gray instead of solid black. In order to see the speckly background more clearly click anywhere on the image with the mouse.
I want to change the speckly black and gray background to solid black without losing image resolution. I tried using the Colors -> Threshold option in GIMP, but it results in losing too much resolution.
I have several different image editors, among them Photoshop, GIMP and Darktable, so the choice of software is not important to me as long as I can obtain a higher quality image. A general solution that works with other colors is not important to me either. If black, white or green is off color I can correct it myself, so for the purpose of answering this question you can assume that the image has already been color corrected to be similar to the image in this question.
I've already tried OCR, but it doesn't work for this situation because OCR introduces small errors into the boot screens which I'm not always able to catch. The boot screens can't have any errors because their purpose is to troubleshoot boot problems, and small errors in the boot screen can result in big problems with booting the computer, so all of the text has to be exactly the same as in the original images.