I have a Mac computer with an Epson printer and was trying to print a copied image using my color cartridges only since my black ink level was too low. Normally I would copy and paste and try to edit the image so that I could easily change the font color and boom it would automatically print in that color HOWEVER because this was a copied image, every time I clicked on it, it just allowed me to move the image etc but not change the preset black color. HOW FRUSTRATING. So using the LibreOffice app for Mac I pasted the image and did the following so that it would change the color.
There is a little paint drop looking icon on the top far right of the toolbar. I simply clicked that and a window popped up and it allows you to change the color of everything in the image. You can adjust the brightness and shading as well as the individual colors of red, green and blue.
Viola, within seconds I had my image color changed so it used my color cartridge only.
Not sure if this is useful to anyone else but thought I would throw it out there.