Two deep K -band ( 2.2 ~ { } { \mu m } ) images , with point-source detection limits of K = 25.2 mag ( one sigma ) , taken with the Keck Telescope in subfields of the Hubble Deep Field , are presented and analyzed .
A sample of objects to K = 24 mag is constructed and V _ { 606 } - I _ { 814 } and I _ { 814 } - K colors are measured .
By stacking visually selected objects , mean I _ { 814 } - K colors can be measured to very faint levels ; the mean I _ { 814 } - K color is constant with apparent magnitude down to V _ { 606 } = 28 mag .