Chemistry

Photography, Publication in the Diário da República - Despacho n.º 8645/2020 - 08/09/2020

6 ECTS; 1º Ano, 1º Semestre, 30,0 PL + 30,0 TP + 10,0 OT

Lecturer
- Maria Teresa da Luz Silveira

Prerequisites
Not applicable.

Objectives
Students should understand general chemistry topics and its application to photographic processes as well as the chemical reactions associated with developent processes.

Program
Theoretical component:
1-Structure of matter: properties of matter; extensive and intensive properties; density and temperature (scales). Classification of matter: mixtures and pure substances. The atoms. The discovery of subatomic particles. Atomic number and isotopes. Ions. Periodic table. Periodic variation of metals, non-metals and metaloids. Electronic configurations and the periodic table: variation of atomic properties.
2-Chemical bonding: Octet rule. Covalent bonds, ionic and metal. Nomenclature of ionic compounds.
3-Stoichiometry: atomic mass, mole, molar mass and chemical reactions. Hit chemical equations; solutions and molarity. Preparation of solutions for weighing, diluting and from concentrated solutions.
4-Acids and bases: acid-base systems Bronsted-Lowry and Ahrrenius. The auto-ionization of water. The concept of pH. PH measurement: indicators and meters. PH electrode sensor. The reference electrode. Operation of the combined electrode. Temperature effect on the pH measurement. Calibration of the pH meter.
5-Oxidation-reduction: Oxidation-reduction reactions; Redox reaction adjustment; Electrochemical cells; Standard reduction potentials.
6-Organic Chemistry: Alkanes and Cycloalkanes. Nomenclature of saturated hydrocarbons. Nomenclature of cycloalkanes. Functional groups: Alcohols and ethers; Aldehydes and ketones; Carboxylic acids; Esters; The amines; Amides; polymers.
7-Chemistry of black and white photography: BW film Constitution. photochemical mechanisms of image formation; Formation of the latent image; Variation of the photosensitivity of silver salts with the wavelength of the radiation; Mechanism of spectral sensitization; Orthocromia, pancromia and infrared sensitization ; most common sensitizers. Revelation; Chemical agents of revelation (reducers); Acid-base balance of Hydroquinone; redox balance of hydroquinone; metol; the development mechanism; The shape of the grain metallic silver after development; physical development and chemical development; The superaditivity; alkali agents; antioxidants; Restrainers; Other agents; The particular case of sodium sulfite; Examples of the developing solutions. Stop bath. Fixation; Fixation mechanism; Composition of the fixing bath. Turning. Washing.


Practical component:
Practical work 1- ab work for the ambiance of students to chemistry laboratory, knowledge of commonly used material, the use of analytical balances.
Practical work 2-laboratory work for the implementation of the stoichiometry of knowledge in the preparation of solutions for weighing, dilution and from concentrated solutions.
Pratical work 3-Practical work of production and optimization of the operating conditions of a solution of developing agent. The optimization is performed by studying the following process variables on the development of a paper positive:pH, development time and concentration of the developing solution.

Evaluation Methodology
Continuous assessment:
To pass the course students have to complete all assignments and respective reports (P, corresponding to 40%) and two written tests on theoretical content (T, correspondig to 60%).
End-of-term assessment:
1 written test

Bibliography
- Chang, R. e Goldsby, K. (2013). Química. New York: McGraw Hill
- Atkins, P. (1989). General Chemistry. New York: Scientific American
- Stroebel, L. e Compton, J. e Current, I. e Zakia, R. (2000). Basic Photographic Materials and Processes.. Boston: Focal Press

Method of interaction
Lectures, theoretical-practical classes and laboratory work involving experimentation with development processes.

Software used in class
Not applicable.