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Encyclopedic Dictionary of Photography

Formula
Formula. — The Term Is Used In Chemistry To Denote A Collection Of Symbols Representing A Compound. The Formula Of A Compound Is Written By Placing Side By Side The Symbols Of The Elements Which It Contains, And Also The Small Figures Indicating The Number Of Combining Proportions Of Each ...

Frauniiofer
Frauniiofer Lines.—certain Dark Lines In The Solar Spectrum Discovered By Fraun Hofer. If A Ray Of Light Be Admitted Through A Narrow Slit In A Dark Room, And This Slit Examined Through A Prism Of Flint Glass, Besides The Spectrum Band Of Colors, A Number Of Lines Will Be Observed ...

Gas Light
Gas Light Is Used In Photography, Chiefly For Exposing Bromide Prints In Contact Print Ing. Its Steadiness Makes It Preferable To Ever-changing Daylight. Gas Light May Also Be Used In The Isochromatic Process, Especially For Copying Oil Paintings, Etc. It Is But Little Used For Portraiture, As The Light Obtained ...

Gelatino Chloride Emulsion
Gelatino-chloride Emulsion Paper.—a Paper Coated With A Gelatino-chloride Emulsion, Containing A Large Quantity Of Citrate. It Prints Out In The Same Manner As With Albumen Paper, Although Much Quicker. The Image Should Be A Little Darker Than Required For The Finished Paper. The Prints Are First Washed In Two Or ...

Glass Paper Or
Glass Paper Or Cloth Is Made By Powdering Glass More Or Less Finely, And Sprinkling It Over Paper Or Calico Still Wet With A Coating Of Thin Glue. When It Is Dry The Powdered Glass Adheres Firmly, And Can Then Be Used For Polishing Woodwork, Etc. Glass Plates.—glass Plays Such ...

Glycerine
Glycerine (formula H, (oh), ; Molecular Weight, 92 ; Synonyms Glycerin, Glycerol, Pro. Phenyl Alcohol). Discovered By Scheele In 1779. It Is A Colorless, Viscid, Neutral, Inodorous Fluic Having A Very Sweet Taste. It Is Soluble In Water And Alcohol In All Proportions, But Insoluble Ir Ether And In Chloroform. ...

Glycin
Glycin (formula C,h,(oh), Nh. Ch„ Co. Oh. Synonym, Hydroxyphenol Obtained By The Action Of Chloracetic Acid On Amidophenol. It Takes The Form Of A Light Lustrous Powder Soluble In Water In Presence Of A Caustic Alkali Or Alkaline Carbonate, Forming A Colorless Solution Which Can Be Rendered Stable By The ...

Gratime
Gratime Is The Standard Unit Of French Measures Of Weight, And Is The Weight Of A Cubic Centimetre Of Distilled Water At 0 Deg. Centigrade (32 Deg. Fahrenheit). It Equals 15.42348 Grains. The English Equivalents For The Other French Weights Corresponding To The Number Of Grammes They Contain Is Easily ...

Ground Glass
Ground Glass Plates.--dry Plates Used Principally For Making Positive Transparen Cies. The Emulsion Is Spread Upon Ground Glass Instead Of Plain, And This Obviates The Necessity Of Framing A Piece Of Ground Glass With The Picture, A Protective Glass Only Being Required. Group.—in Art, The Term Is Used To Signify ...

Hydrochloric Acid
Hydrochloric Acid (formula, Hci; Molecule Weight, 36.5; Synonyms, Chlorhydric Acid, Hydrogen Chloride, Muriatic Acid, Spirits Of Acid Is Found In Nature Among The Gases Emanating From The Active Volcanoes, And Occasionally In The Spring And River Waters Which Take Their Rise In Volcanic Districts, Especially In South America. It Is ...

Hydrofluoric Acid
Hydrofluoric Acid (formula, Hf; Molecular Weight, Zo; Synonyms, Fluorhydric Acid, Hydrogen Fluoride Acid Obtainable Either In Liquid Or Gaseous Form. It Is Prepared By Decomposing Calcium Fluoride By Sulphuric Acid, And By Heating Acid Potassium Fluoride. Its Chief Use Is In Etching Glass, As It Decomposes And Dissolves Silicates. Glass, ...

Hydrometer Or
Hydrometer Or Areometer.—an Instrument For Determining The Specific Gravities Or Relative Densities Of Liquids. The Principle Upon Which It Works Is That When A Body Floats On A Liquid, And Thus Displaces A Quantity Of The Liquid, The Weight Of The Solid Body Is Equal To The Weight Of The ...

Hydroxylamine Hydrochloride
Hydroxylamine Hydrochloride (formula, Molecular Weight, 69.5; Synonym, Oxyammonium Tubular Crystals, Very Soluble In Water And Alcohol. The Best Method Of Preparing It Is Probably The Following, Given By Ruschig:— Hydrogen Sulphite In Concentrated Aqueous Solution Is Added To An Alkaline Nitrate At A Temperature Not Exceeding Freezing If The Soda ...

Hydroxyphenol
Hydroxyphenol Olycin.—see Glycin. Hygrometer.—an Instrument For Measuring The Degree Of Moisture Of The Atmo Sphere. The Principle Of These Hygrometers Depends Chiefly Upon Absorption Or Condensation. An Instrument Of This Kind Is Often Useful In The Photographic Laboratory To Detect The Amount Of Moisture In The Atmosphere. A Very Simple ...

Iiydroquinoni3
Iiydroquinoni3 (formula ; Molecular Weight, Ito ; Synonyms, Quinol, Hydro Kinone, Hydrochinone, Pyroguinol, Pyrogentisic Constant Product Of The Action Of Reducing Agents On Quinone. The Most Convenient Method Of Preparing It Is By Passing Sulphur Dioxide (sulphurous Acid Gas) Through A Warm Saturated Solution Of Quinone. It Is Also Prepared ...

Illuminating
Illuminating Lens.—a Large Lens, Which Has For Its Purpose The Concentration Of The Light From The Sun Or A Lamp At The Focus, Is Sometimes Termed An Illuminating Lens. Condenser Is, However, The More General Term. Illumination.—the Illumination Of A Surface Varies Inversely As The Square Of Its Dis Tance ...

Ink
Ink Process.—a Method Of Obtaining Positive Prints In Ordinary Writing Ink. A Good Quality Of Paper Is First Immersed In A Nearly Saturated Solution Of Potassium Dichromate, And Dried In The Dark. When Dry, The Paper Will Have A Bright Yellow Color. It Is Then Placed Under The Negative In ...

Instantaneous
Instantaneous Photooraphy.—in The Very Earliest Days Of Photography This Term Was Applied To What Would Now Be Considered Very Slow Work Indeed. We Now Usually Apply This Term When The Exposure Does Not Exceed One Second. In Some Cases This Only Amounts To The One-thousandth Part Of A Second. This ...

Ivorine
Ivorine. —imitation Ivory, A Compound Of Caoutchouc, Sulphur, And Some White Ingredi Ents, Such As Gypsum, Sulphate Of Baryta, Oxide Of Zinc Or Pipeclay. A Good Formula For Making Artificial Ivory Is As Follows : White Shellac Zo Ounces Acetate Of Lead 4% Ounces Ivory Dust 8 Ounces Camphor 5 ...

Kallitype
Kallitype Process.—a Printing Process Giving A Dull Matt-surfaced Picture, Similar To Platinotype Of Bromide Paper. The Formula For The Manufacture Of The Paper Is Not Published The Paper Is, However, Sold Commercially. The Paper Is Much More Sensitive Than Ordinary Albuminized Paper ; It Will, Therefore, Be Necessary To See ...

Latent
Latent Image.—the Name Given To The "latent " Or Invisible Image, Resulting From The Impact Of Light Upon The Sensitive Photographic Plate. This Image, Although Invisible To The Eye, Quickly Becomes Perceptible When Treated With A Reducing Agent Termed A Developer. The Theory Of The Latent Image Is Surrounded In ...

Librarian Of Congress
Librarian Of Congress, Washington, D. C., To Perfect The Copyright. The Freight Or Postage Must Be Prepaid, Or The Publications Inclosed In Parcels Covered By Printed Penalty Labels, Furnished By The Librarian, In Which Case They Will Come Free By Mail (not Express), Without Limit Of Weight, According To Ruling ...

Luminous
Luminous Paint.—a Phosphorescent Luminous Paint, Consisting Of Roo Parts By Weight Of Carbonate And Phosphate Of Calcium, (obtained By Calcining Sea Shellst) Mixed Well Together, Too Parts Of Pure Lime And 25 Parts Of Calcined Sea Salt, Both Measured By Weight. Half The Amount Of The Whole Weight Of Sulphur ...

Magic
Magic Photographs.—a Process For Making These Was First Pointed Out By Sir John Herschel. Prints On Albumenized Paper Were First Made And Fixed Without Any Toning. They Are Then Washed Thoroughly And Immersed In A Saturated Solution Of Perchloride Of Mer Cury. The Action Of This Solution Is To Bleach ...

Metol
Metol. (formula: H„ No.) Metol Is The Trade Name Given To The Sulphate* Of Methyl Paramidometacresol. It Takes The Form Of A Whitish Powder Soluble In Water. A Solution Of It With Alkalies In Presence Of Alkaline Sulphites Will Remain Colorless For A Great Length Of Time. Employed With Alkaline ...

Metric
Metric System.—the System Adopted By The French Convention In 1879, But Which Is Gradually Coining Into Use In This And Other Countries. The Theory Of The System Is That The Meter Is A '0,000,000th Of A Quadrant Of The Earth Through Paris, The Liter Is A Cube Of Meter, The ...

Military
Military Photography.—photography Was, Employed For Military Purposes As Far Back As 1854, When, During The Crimean War, Two Army Officers Were Specially Instructed For The Purpose In The Wet And Dry Collodion Processes. The Results Obtained Are Said To Have Been So Satisfactory As To Lead To The Establishment Of ...

Mirror
Mirror Photography.—quite A Num Ber Of Novel Effects Can Be Obtained By The Aid Of One Or More Mirrors. If Two Mirrors Are Taken And Placed Parallel To One Another, And A Person Placed Between, The Effect Obtained Is As Shown In Fig. 277, Where One Soldier Appears As A ...

Moonlight
Moonlight Photography.—with Gel Atine Dry Plates Of Extreme Sensitiveness It Is Possible To Make Photographs By Moonlight, Only A Very Long Exposure Is Required. Fig. 284 Is A Good Example Of Moonlight Photography. It Was Made By Mr. F. A. Demuth With A Bausch & Lomb R. R. Lens F8, ...

Motion
Motion, Photooraphino.—the Representation Of Motion By Photography Is By No Means An Easy Task. Artists Manage To Give Us Pictures In Which We Get Motion Depicted, Yet Some Will Tell You That These Are Wrong En Tirely. The Artist Has Made A Horse Galloping; It Ap Pears To Our Ey ...

Mounting Canvas
Canvas, Mounting On.—albumen, Or Other Prints Can Be Mounted On Canvas. First Soak The Canvas In A Gelatine Or Glue Solution, Then Sketch Upon A Wooden Frame. When Dry And Perfectly Tight, The Prints Can Be Readily Mounted With Starch Paste. This Is A Convenient Method When Large Prints Are ...

Natural Color
Natural Color Photography.—see Heliochromy. • Naturalistic.—the Dictionary Meaning Of This Term Is—in Accordance With Nature. The Term Has Recently Been Applied To Photographs Made Slightly Out Of Focus. This Was First Advocated By Sir W. J. Newton, A Miniature Painter, About The Year 2856. Later On, In The Year 1874, ...

Neatsfoot
Neatsfoot Oil—an Oil Obtained From The Feet Of Neat Cattle. Negative.—the Term Applied To The Image Of An Object Or Objects, And In Which The Lights And Shades Are Reversed. A Negative Is Usually Made By Direct Action Of The Light On The Camera. The Image Shining Upon The Sensitive ...

Negative
Negative Dryer.— Many Attempts Have Been Made To Devise A Machine By Which Negatives May Be Dried In The Shortest Possible Time. The Most Successful Have Been Those Which, By A Centrifugal Motion, Create A Strong Current Of Air Which Takes Away The Moisture Much Sooner Than By Applying Heat. ...

Negative_2
Negative, Enlarging.— —the Crudest And Least Recommendable Method Of Enlarging A Gelatine Negative Is, To Simply Soak It In Water Containing About One-twelfth Of Its Volume Of Strong Liquid Ammonia. It Two Or Three Hours The Film Will Be Found To Have Frilled From The Plate And Extended To A ...

Negative_3
Negative Numberer.—an Arrangement For Numbering Negatives. The Most Ingeni Ous Form Is That Devised By Kruse, Of Berlin, And Which Is Thus Described :—a Small Benzine Light (or Candle) Is Placed In A Metal Lantern, So Constructed Both With Regard To The Admission Of Light And The Letting Out Of ...

Nh 2nh
+ 2nh, = Nh,c1. If Ammonium Sulphide Be Used Instead Of Ammonia The Mercurous Chloride Will Be Split Up Into Mercuric Sulphide And Finely Divided Mercury, And The Silver Chloride Will Become Converted Into A Form Of Silver Sulphide. By This Means We Get A Very Dense Negative, The Process ...

Nicols
Nicol's Prism—an Instrument For Polarizing Light, Named After The Inventor. It Is Formed From A Rhombohedron Of Iceland Spar Thrice As Long As Its Diameter. This Is Bisected In The Plane, Which Passes Through The Obtuse Angle. The New Faces, Being Polished, Are Cemented Together Again By Canada Balsam. A ...

Nitric Acid
Nitric Acid (formula, Hno,; Molecular Weight, 63 ; Synonym, Aqua Fortis). A Heavy, Colorless Liquid Prepared By The Action Of Strong Sulphuric Acid Upon Potassium Or Sodium Nitrate. The Strongest Obtainable Possesses A Specific Gravity Of About 1.5, But A Large Proportion Of What Is Now Sold As Nitric Acid ...

Nomenclature
Nomenclature, Photooraphic.—the Nomenclature Of The Various Photographic Inventions And Processes Seems To Have Been Carried Out Without The Slightest Regard To Law Or Order. The Most Absurd And Meaningless Words Have Been Adopted, And Which Are In Many Cases Liable To Lead The Student Astray. At An International Photographic Congress ...

Non Actinic
Non - Actinic Fledia.—media For The Transmission Of Non-actinic Rays Of Light. The Color Of This Depends Greatly Upon The Nature And Sensibility Of The Material To Be Handled. It Vanes From A Deep Ruby To A Pale Orange. Abney Recommends Bookbinders' Red Cloth Combined With Stained Red Glass. It ...

Obscure
Obscure Rays.—invisible Rays Above And Below Those Of The Visible Spectrum. (see Spectrum.) Oil.—the Term Oil Is Generally Applied To All Neutral Fatty Substances Which Are Liquid At )rdinary Temperatures. They May Be Divided Into Two Great Classes,* Fixed Oils And Essential Oils. • Rodwell's " Directory Of Science." Oils ...

Opal Glass
Opal Glass Is Made By Fusing One Of The Oxides Of Tin Or Zinc With The Metal. It Is Sold For Photographic Purposes In Two Different States, I.e., "plain" And "smoothed," The Former Possessing The Natural Polished Surface Of The Glass, And The Latter Being Very Finely Ground. The Latter ...

Optical
Optical Center.—every Lens Possesses A Cer Tain Point, Situated On Its Principal Axis, Termed The Optical Center. At This Point Every Incident Ray Which Passes Through It Does Not Undergo Deviation, But Pursues A Path Parallel To Its Original Course. Only Single Lenses Have Perfectly True Optical Centers In An ...

Optical
Optical Lantern.—an Apparatus Employed For Projecting Magnified Images Upon A White Screen. The Rays Emanating From An Artificial Source Of Light Are Collected Together And Passed Through A Transparent Positive Picture, Which By The Divergence Of The Rays Through A Lens Is Thrown Brilliantly Illuminated And Magnified On A Screen. ...

Optical Instruments
Optical Instruments, Preserving.— All Optical Instruments, If Required To Be Kept In Good Working Order, Should Be Carefully Preserved From Light And Moisture, Which Have A Peculiarly Ruinous Effect Upon The Glass. Lenses, When Not Required For Use, Should Be Kept In Small Chamois Leather Bags Made To Fit. If ...

Optics
Optics Was Defined By Sir David Brewster As That Branch Of Knowledge Which Treats Of The Properties Of Light And Vision As Performed By The Human Eye. The Modern Divisions Of This Science May Be Stated To Be As Follows :—(i) Light And Its Sources ; (2) Transmission, Velocity, And ...

Oreenlaws
Oreenlaw's Process.—a Modification Of The Old Calotype Paper Negative Process. It Is Thus Described : Thin Negative Paper Is First Selected, Quite Free From Holes And Of Equal Thickness. Then Make Up A Solution Of Potassium Iodide ',boo Grains Potassium Bromide 300 Grains Distilled Water 40 Ounces Then Add Enough ...

Orthoc1iromatic Or Isochromatic
Orthoc1iromatic Or Isochromatic Process.—a Process Of Obtaining Photo Graphic Images Of Colored Objects In True Relative Tone Values. To Obtain This, By Counteracting The Opposite Effect That Colors Have Upon The Photographic Plate To That Upon The Retina Of The Eye Certain Dyes Are Used. The Facts Are These*, That ...

Orthochromatic
Orthochromatic Screen.—all Orthochromatic Plates Prepared By Any Of The Methods At Present Known Still Remain Far Too Sensitive To The Blue And Violet Rays. It Therefore Becomes Necessary To Interpose Between The Object And The Plate A Yellow Transparent Screen Which Has The Power Of Cutting Off A Certain Portion ...

Orthochromatic Collodion
Orthochromatic Collodion Emulsion.—a Collodion Emulsion Rendered Ortho Chromatic By The Addition Of So•called Color-sensitizers, The Effect Of Which Is To Produce Photo Graphic Negatives More Correct With Regard To The Color Gradations As Apparent To The Eye. Mr. J. M. Eder's Formula Is As Follows : The Emulsion Is Prepared ...

Orthochromatic Or Isochromatic
Orthochromatic Or Isochromatic Plates.—photographic Plates Prepared With A Dye, Either Added To The Emulsion Previous To Coating The Glass, Or Applied In Solution To The Ordinary Gelatino-bromide Dry Plate. By This Means Better And Truer Color Gradation Is Obtained. These Plates May Be Obtained Commercially, And Are Equally Adapted For ...

Orthociiromatic Or Isociiromatic
Orthociiromatic Or Isociiromatic Photography.—synonymous Terms Applied To A Process Of Obtaining Photographic Images Of Objects In, Or Nearly In, Their True Respective Tone Values. Ordinary Gelatine Plates Do Not, As Is Well-known, Represent Objects In Their True Relative Degrees Of Light And Shade As Apparent To The Eye, For The ...

Oxygen
Oxygen (symbol, 0 ; Atomic Weight, I6).—the Most Abundant Element. It Is Present In The Air We Breathe, It Forms :ths (by Weight) Of Water, And Is Present, To A Great Extent, In The Solid Part Of The Earth. Oxygen Can Only Be Obtained From Something That Contains It. For ...

Panoramic Camera
Panoramic Camera. — A Camera Specially Constructed As To Enable Photographs Embodying A Very Large Angle Of View To Be Taken, Usually Upon A Curved Surface. The First Camera Of This Kind Was Constructed By Mr. Martens, Of Paris, In The Year 1847, For Cylindrical Daguerreotype Plates. Then Followed The ...

Papyrotint
Papyrotint Process.—a Photo-lithographic Process Invented By Husband. It Is A Modification Of Captain Abney's Improved Method Of Papyrotype. It Is Specially Suitable For The Reproduction Of Subjects In Half-tone. The Advantage It Possesses Over Other Methods Are That A Transfer Can Be Taken In Greasy Ink, For Transfer To Stone ...

Perforating
Perforating Glass.—to Make A Hole In Glass, An Ordinary Well-tempered Steel Drill Is The Best Tool. The Drill Must Be Kept Moistened With Turpentine In Which Some Camphor Has Been Dissolved, Or With Diluted Sulphuric Acid, Or With Ordinary Kerosene Oil. Perrianency.—the Question Of The Permanency Of Photographic Images Is ...

Photo Crayon
Photo Crayon Process.—a Process Introduced By Sarony About The Year 187o. It Contained In Making A Photographic Transparency On Glass, Which Was Afterwards Backed Up With Paper, On Which A Number Of Lines, Hatchings, Or Stippling Were Lithographed, Giving The Portrait The Appearance Of A Crayon Work. A Similar Process ...

Photo Galvanographic
Photo-galvanographic Process.—a Photo-mechanical Process Now No Longer Used, Although Many Of The Present Secret Processes Are Based Upon It. Pretsch's Photo-galvanographic Process May Thus Be Briefly Described. A Glass Plate Was First Coated Over With Gelatine Containing Potassium Dichromate Or Silver Salt And Other Chemicals. When Dry It Was Exposed ...

Photo Mechanical
Photo-mechanical Processes.—the Term Photo-mechanical Is Applied To All Pro Cesses In Which The Action Of Light Upon Chemical Substances Becomes The Means Of Preparing Printing Surfaces From Which Many Impressions Can Be Made Without Any Further Assistance Of Light. The First Photo-mechanical Process Known Was That Invented By Nicephore Niepce ...

Photo Relief
Photo-relief Enoravino.—processes In Which, By Photography And Subsequent Man Ipulation, A Printing Surface Is Obtained, Which Stands Above The General Surface, And Receives The Ink In The Same Manner As Type. Wood-cuts Come Under This Heading. The Woodbury Pro Cess Is Often Termed A Photo-relief One, Although Here The Image ...

Photographic
Photographic Cheriistry.—the Number Of Chemical Changes That Take Place In Pho Tographic Operations Is So Great That It Will Only Be Possible To Mention The Most Important. The Process That Is Now Almost Universally Adopted Is The Gelatino-bromide Dry Plate Process. This Has Taken The Place Of A Large Number ...

Photographing Wood
Wood, Photographing On.—there Are A Variety Of Processes For Photographing Upon Wood, And For Ordinary Decorative Processes Any Of Them Can Be Used, Such As The Carbon Transfer Process, The Powder Process, Transferrotype, Etc. But The Principal Object Of Producing Images Upon Wood Is Now Usually For The Purpose Of ...

Or Alto Alto Relievo
Alto Relievo, Or Alto Rilievo.—a Term Used Principally In Photo-sculpture. The Term Should Only Be Applied When The Figures Project More Than Half Their True Proportions. When They Project, Exactly One-half, The Term Used Is Mezzo Relieve, And If Less Then Half, Basso Relieve, Or, In English, Alum.—the Name Given ...

Or Astronomical Photography
Astronomical Photography, Or Astro-photography.—in The Very Earliest Days Of Photography Attempts Were Made To Photograph Celestial Bodies. In 1838 Daguerre Attempted To Photograph The Moon, But Was Unsuccessful. In 1840 Some Experiments By Dr. Draper, Of New York, Resulted In The Production Of Lunar Photographs 1 Inch In Diameter. In ...

Or Bleaching Powder
Bleaching Powder, Or Calcium Hypochlorite, Is Prepared By Passing Chlorine Over Slaken Lime. It Decomposes Rapidly And In Different Ways By Keeping. Its Uses In Photography Are Based Upon The Fact Of Its Containing Chlorine In Such A Loose Form That Any Acid Will Liberate It. See Calcium Hypochlorite. Blind ...

Or Film Negative Process
Film Negative Process, Or Film Photography, Is A Term Applied To Processes In Which Flexible Films Are Used Instead Of Glass Plates. As Far Back As 1855 Scott Archer Patented A Method Of Coating Collodion Negatives With A Solution Of Gutta-percha In Benzole. When Dry The Film Was Separated From ...