There are a few considerations here:
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Black ink in this printer model is pigmented while the color inks are dye based. The pigmented ink is not compatible with photo paper. If photo paper is selected (or automatic paper type is selected and detected as photo paper) the printer will use only the color cartridges to print.
The black ink is designed for text printing and the ink droplets are much larger than the color droplets. To print better quality color ink is typically used for printing graphics as it gives better print quality with less visible dots.
Depending on the printer model and operating system some drivers have an option for "print in grayscale" and "use black cartridge only". I do not know if this is available for your printer in a Mac OS. You may have better results asking your question in the more appropriate Mac Printing/Scanning forum.