A method of dispensing reagent onto a biological sample comprising: overlaying a protective fluid layer onto a biological sample , the biological sample being disposed on a support medium; dispensing reagent droplets of between about 1 pL to about 50 pL such that the reagent droplets penetrate the protective fluid layer and contact the biological sample ; wherein the reagent droplets comprise a reagent composition selected from the group consisting of a primary stain reagent composition and an antibody reagent composition; wherein a mass of the reagent deposited onto the biological sample is variable based on a particular biological sample and/or assay by (i) applying reagent by multiple passes of a dispensing mechanism, (ii) varying the dots per inch (dpi) of reagent dispensing, (iii) varying the droplet volume, and/or (iv) varying the reagent concentration, wherein the reagent droplets are dispensed at a velocity of between about 5m/s to about 15 m/s, wherein a kinetic energy of the reagent droplets is greater than a surface tension of the protective fluid layer, wherein the primary stain reagent composition comprises a dye, a surfactant, and a viscosity modifier, wherein the composition has a viscosity ranging from about 0.001 Pa·s (1 cp) to about 0.04 Pa·s (40 cp) and a surface tension ranging from about 25·g/s 2 (25 dyne/cm) to about 45·g/s 2 (45 dyne/cm), wherein the antibody reagent composition comprises a primary antibody, a surfactant, and a viscosity modifier, wherein the composition has a viscosity ranging from about 0.004 Pa·s (4 cp) to about 0.007 Pa·s (7 cp), and a surface tension ranging from about 20·g/s 2 (20 dyne/cm) to about 40 g/s 2 (40 dyne/cm). overlaying a protective fluid layer onto a biological sample , the biological sample being disposed on a support medium; dispensing reagent droplets of between about 1 pL to about 50 pL such that the reagent droplets penetrate the protective fluid layer and contact the biological sample ; wherein the reagent droplets comprise a reagent composition selected from the group consisting of a primary stain reagent composition and an antibody reagent composition; wherein a mass of the reagent deposited onto the biological sample is variable based on a particular biological sample and/or assay by (i) applying reagent by multiple passes of a dispensing mechanism, (ii) varying the dots per inch (dpi) of reagent dispensing, (iii) varying the droplet volume, and/or (iv) varying the reagent concentration, wherein the reagent droplets are dispensed at a velocity of between about 5m/s to about 15 m/s, wherein a kinetic energy of the reagent droplets is greater than a surface tension of the protective fluid layer, wherein the primary stain reagent composition comprises a dye, a surfactant, and a viscosity modifier, wherein the composition has a viscosity ranging from about 0.001 Pa·s (1 cp) to about 0.04 Pa·s (40 cp) and a surface tension ranging from about 25·g/s 2 (25 dyne/cm) to about 45·g/s 2 (45 dyne/cm), wherein the antibody reagent composition comprises a primary antibody, a surfactant, and a viscosity modifier, wherein the composition has a viscosity ranging from about 0.004 Pa·s (4 cp) to about 0.007 Pa·s (7 cp), and a surface tension ranging from about 20·g/s 2 (20 dyne/cm) to about 40 g/s 2 (40 dyne/cm). <EOS>