TECHNOLOGY FOCUS - IMAGING AND COMMUNICATION - Preferred Ink: The ink is a paste exhibiting non-newtonian rheology.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The silicon/germanium-based inorganic nanoparticles comprises elemental silicon, elemental germanium, their mixtures or alloys. The inorganic nanoparticles comprise a dopant. The silicon/germanium-based nanoparticles comprise silicon oxide, silicon nitride, and/or silicon oxynitride. The substrate comprises a silicon wafer. The acidified aqueous solution comprises solubilzed HCl and a solubilized carboxylic acid.    TECHNOLOGY FOCUS - POLYMERS - Preferred Method: The separating is performed with centrifugation. The method (M2) further involves adding solvent to the separated polymer to form a re-suspended polymer and performing an additional separation on the re-suspended polymer to form a further purified polymer. The method (M2) further involves mixing the acidified polymer solution for at least 10 minutes prior to performing the separation. The method (M2) further involves performing initial processing of the polymer prior to forming the acidified solution, where the initial processing involves: forming a suspension of the polymer in a solvent; separating the polymer to form an initially purified polymer; and suspending the initially purified polymer in an acidic solution to form the acidified solution. The filtration is repeated to further reduce transition metal contamination of the polymer. The purified polymer has an iron contamination, chromium contamination, copper contamination and nickel contamination individually of no more than 40 ppb, as evaluated in a 7 wt.% solution of polymer. The polymer solution during purification has a concentration of 0.01-15 wt.% of polymer. Preferred Components: The organic polymer comprises a cellulose-based polymer. The polysaccharide comprises a cellulose ether. The cellulose polymer comprises ethyl cellulose. The cellulose polymer has metal contamination for any individual metal of no more than 400 ppb as evaluated in a 7 wt.% polymer solution; has iron contamination, chromium contamination, copper contamination or nickel contamination individually of no more than 50 ppb as evaluated in a 7 wt.% polymer solution; has metal contamination levels of no more than 100 ppb for any metal as evaluated in a 7 wt.% polymer solution. The polymer comprises an ether cellulose and the acidified solution comprises water. The polymer solution comprises an alcohol. Preferred Nanoparticle: The nanoparticle paste further comprises an alcohol solvent. The nanoparticle paste comprises 0.5-15 wt.% of inorganic nanoparticles and at least 2 wt.% of polymer, and where the polymer comprises ethyl cellulose. EXAMPLE - No suitable example given.