Adjustments to the concentration of water and salts within the urine takes place mainly in the distal parts of the tubules and in the collecting tubules, by altering the permeability of the membranes of cells lining the nephron walls. These changes are brought upon to two hormones, ADH and aldosterone.
Use for Colorimetric and Turbidimetric Determinations. These photometric colorimeters use specific light filters to give readings on a unique KlettTM scale. The readings are directly proportional to the concentration or optical density of a solution, in accordance with Beers Law.
What about using photo corners? As far as pressure-sensitive (sticky) tape goes, Filmoplast P90 and Filmoplast P are much better than most, but photo corners don't leave adhesive residue on the photo. Gummed tape (linen or archival paper) is a good option too, as long as it's not too wet for the photo paper.