CLAY Clays are minerals composed of hydrated aluminum silicates, often containing large amounts of crystalline silica. Other impurities may include organic matter or sulfur compounds. Sometimes, grog (ground firebrick), sand, talc, vermiculite, perlite, and small amounts of minerals such as barium carbonate and metal oxides are added to modify clay properties. Clays can be worked […]
Read MoreMixing Photo Chemicals can be bought in liquid form, which only needs diluting, or powder form, which needs dissolving and diluting. Hazards Developer solutions and powders are often highly alkaline, and glacial acetic acid, used in making the stop bath, is corrosive by skin contact, inhalation and ingestion. Developer powders are a potential skin and […]
Read MoreHAZARDS Oil-based inks contain treated linseed oils. While linseed oil is not considered a hazard by skin contact or inhalation, it is also not recommended to ingest any amounts of linseed oil. Oils are flammable when heated, and rags soaked in these will ignite by spontaneous combustion. PRECAUTIONS Know and understand what materials are used. […]
Read MoreHazards Rubber cement, a common adhesive used with collagraphs, is extremely flammable and most rubber cements and their thinners contain the solvent n-hexane, which can cause damage to the peripheral nervous system (hands, arms, legs, feet) from chronic inhalation. Epoxy glues can cause skin and eye irritation and allergies. Spraying fixatives on the back of […]
Read MoreHazards See the developing section of black-and-white processing for the hazards of standard black-and-white developers. In general, color developers are more hazardous than black and white developers. Paraphenylene diamine, and its dimethyl and diethyl derivatives, are known to be toxic by skin contact and absorption, inhalation, and ingestion. Recent color-developing agents such as 4-amino-Nethyl-N-[P-methane- sulfonamido […]
Read MoreAcid Etching Etching involves use of dilute nitric acid, Dutch mordant (hydrochloric acid plus potassium chlorate) or ferric chloride to etch the zinc or copper (respectively) metal plate. Unetched parts of the plate are protected with resists such as stop-out varnishes containing ethyl alcohol, grounds containing asphaltum or gilsonite and mineral spirits, rubber cement, and […]
Read MorePlate and Stone Preparation A variety of drawing materials with high wax and fatty acid content are used to make the image, including tusche and lithographic crayons. Airbrushing liquid drawing materials or using spray enamel or lacquer is also common. Other materials used in stone or plate processing include etch solution containing acids and gum […]
Read MorePhotolithography Photolithography involves transferring graphic images to stones or metal plates that are coated with a light-sensitive emulsion. One can coat the stone or metal plate, or use pre-sensitized metal plates. Lightsensitive emulsions used on stone consist of a mixture of powdered albumin, ammonium dichromate, water, and ammonia; commercial emulsions are usually based on diazo […]
Read MoreHazards Some woods used for woodcuts can cause skin irritation and/or allergies. This is particularly true of tropical hardwoods. Accidents involving sharp tools can result in cuts. Caustic soda (sodium hydroxide) is sometimes used for etching linoleum. It can cause skin burns and severe eye damage if splashed in the eyes. Eating, drinking or smoking […]
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