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Photography Theory and Practice

Non Actinic Lighting Dark Room Lamps
Non-actinic Lighting Dark-room Lamps And Safelights 246. General Principles. The Choice Of Illumina Tion To Be Used When Handling Sensitive Material, Either (luring Manufacture Or During The Various Operations Prior To And Including Fixation, Must Be Guided On The One Hand By The Distribution Of The Spectral Sensitivity Of The ...

Organic Developers 347
Organic Developers 347. The Developing Function. With The Exception Of Certain Derivatives Of Hydroxyl Amine And Hydrazine Already Mentioned (§ 345), And Of Which None Is Used In Practice, All Organic Developers Belong To The Aromatic Series (deriva Tives Of Benzene, Toluene, Naphthalene, And Other Coal-tar Substances). Laws Making It ...

Papers 625
Papers 625. Cyanotype Paper. Cyanotype Paper (h. Pellet, 1878) Yields Copies Consisting Of Blue Lines On A White Ground When Printed Under A Tracing. This Paper, Which Is Impregnated With A Mixture Of Ferric Salts And Gum Arabic, Has A Sensitivity Comparable With That Of The Fastest Ferro-prussiate Papers, And, ...

Perspective Monocular Andbinocular
Perspective : Monocular And Binocular Vision 22. Geometrical Perspective. The Perspective Of An Object Or Of A Group Of Objects (from The Latin : To See Across) Is The Trace Of All The Points Of Intersection Of All The Straight Lines From A Fixed Point (the Viewpoint Or Centre Of ...

Photo Mechanical Processes In Brief
Photo-mechanical Processes In Brief 911. Generalities. The Various Processes Which Are Used On A Commercial Scale At The Present Time For The Photo-mechanical Reproduction Of Drawings In Line Or Wash, Paintings And Photo Graphic Originals May Be Classified Into Three Main Groups— Typographic Or Letterpress Processes—among Which Are Line Photo-etching ...

Photographic Images Theideal
Photographic Images : The Ideal Scientific Image ; The Aesthetic Image 18. Negative And Positive. The Image Obtained. By The Usual Photographic Processes Is A Nega Live (fig. 2), In Which The Lights In The Subject Are Reproduced As Opacities And The Shadows As Transparencies. The Photographic Reproduction Of This ...

Physical Development Before Or
Physical Development Before Or After Fixing 395. Physical Development Before Fixing. Physical Development, Which Consists In The Deposition Of Nascent Silver Formed In The Developer On The Nuclei Of The Latent Image, And Which Is The Normal Method Employed For Exposure Test The Effect Of Bromide On A Developer. This ...

Pigment Processes 635
Pigment Processes 635. Advantages Of The Carbon Process. The Carbon Process Is Unquestionably The Most Beautiful Printing Process That A Photographer Can Employ When He Is Not Aiming At A Personal Modification Of The Negative. It Is One Of The Most Flexible In Regard To Choice Of Colour And Of ...

Plates Papers
Papers, Plates, And Films For Positive Prints By Development 547. Different Kinds Of Emulsions And Their Characteristic Qualities. The Different Emulsions To Be Considered Are : Gelatino-bromide For Black Tones ; Gelatino-chloride For Black Tones—these Sometimes Contain A Small Proportion Of Silver Bromide ; And Gelatino-chlorobromide Of Very Fine Grain ...

Platinum Iron Printing Papers 630
Platinum-iron Printing Papers 630. Platinum Papers. Pictures Consisting Of Reduced Metallic Platinum May Be Obtained By Methods Similar To Those Indicated In The Two Preceding Paragraphs By Using Potassium Chore Platinite Instead Of Silver Nitrate. The Com Mercial " Platinum " Papers Are Similar To Kallitype Paper In That They ...

Practical Enlarging 765
Practical Enlarging 765. Fixing The Sensitive Paper In Position. With Vertical Enlargers The Placing Of The Paper Is Usually Done By Metal Squares Or Strips Which Act Both As Masks With Variable Openings And As Pressure Plates, Holding The Paper Fiat. Failing These, The Paper May Be Held Down By ...

Preparation And Properties Of
Preparation And Properties Of Negatives-gelatino-bromide Emulsions 192. Preparation Of Emulsions. Rapid Negative Emulsions Are Usually Prepared By Pouring A Neutral Or Ammoniacal Solution Of Silver Nitrate Into A Slightly Warm Solution Of Gelatine Con Taining Potassium Bromide With A Small Propor Tion Of Iodide. The Mixing Requires To Be Done ...

Principles Of Three Colour Methods
Principles Of Three-colour Methods 865. General Notes. The Concept Of Ducos Du Hauron, As Set Out In His Publications, May Be Summarized As Follows (e. Wallon). Any Colour, Natural Or Artificial, Is A Combina Tion Of The Elementary Rays Contained In White Light And Which The Spectrum Shows Us Dis ...

Printing Papers And Printing
Printing Papers And Printing Methods 491. The Principal Printing Processes. A Great Number Of Photo-chemical Reactions Are Known On Which Processes For Producing Photographic Positives Can Be Based. There Arc Also Various Reactions By Means Of Which The Substance Of The Image Produced By The Action Of Light Can Be ...

Prints 881
Prints 881. Tricolour Transparencies. It Is Not Pos Sible In This Volume To Describe In Detail The Numerous Working Methods By Which Tricolour Transparencies Can Be Obtained By Superposing In Register Three Images On Film. We May Men Tion, As Very Suitable For Obtaining The Three Elementary Monochromes For This ...

Professional Stand Cameras Commercial
Stand Cameras : Commercial, Professional, And Semi-professional 148. General Notes. The Photographic Camera No Longer Inherits The Primitive Simplicity Of The Daguerreotype Box, To Which The Familiar Term " Camera Obscura " Could Be Strictly Applied, And Which Consisted Of A Box Into Which Light Was Admitted Only Through The ...

Projection Lanterns 784
Projection Lanterns 784. Parts Of The Lantern. A Projection Lan Consists Essentially Of A Light-source Of High Power Enclosed In The Lantern Proper Or Light-box, A Condenser, A Slide Carrier, Enabling The Slides Tb Be Changed Rapidly, And A Lens. The Lantern Is Usually Placed On A Stand, Bringing The ...

Quantity Of Light 12
Quantity Of Light 12. Intensity And Brightness. The Luminous Power Of The Source Is Determined By Its Intensity And Indirectly By Its Brightness. The Intensity Is Measured In Decimal Candles, Or, For Short, In Candles, Of Perfectly Definite Intensity, Which Differs Only Slightly From That Of The Candles Ordinarily Used ...

Reduction 457
Reduction 457. Choice Of A Reducer. The Usual Reducers Act By Gradually Dissolving The Silver Which Forms The Photographic Image, But Widely Different Results Are Obtained According To The Substance (or Mixture Of Substances) Which Is Used For This Purpose. Uniformity Of Action Of A Reducer Is Obviously Only Possible ...

Reduction Methods Of After Treatment
Methods Of After-treatment : Intensification, Reduction, Working-up, Retouching 444. General Considerations. Of The Various Corrective Operations Described In This Chapter, Intensification And Reduction Are Purely Chemical Manipulations, Whilst The Others, Retouching, Etc. (including The Local Application Of Intensifiers And Reducers), Arc Processes Requiring Manual Skill, And Presuppose Some Artistic Knowledge ...

Retouching 473
Retouching 473. The Purpose Of Retouching. As A Rule, The Term " Retouching " (negative Retouching) Is Used To Describe Work Done On The Gelatine Of A Negative With A Pencil And Scraper. Retouch Ing Corrects Certain Technical Faults In Negatives And, Above All, Faults Of Modelling. It Is An ...

Reversal Processes Methodsfor
Reversal Processes : Methods For Obtaining Direct Positives 437. General Considerations. We Will First Men Tion A Method Which Cannot, Properly, Be Con Sidered As A Reversal Process, But Which Is Some Times Employed For Obtaining Positive Images Directly. By Developing So As To Obtain Silver, Which Is Whitish By ...

Salted Paper And Albumen
Salted Paper And Albumen Paper 523. Salted Paper. Salted Papers Are Sized With Starch 1 Paste Containing A Suitable Quan Tity Of Chlorides And Other Soluble Salts, Which Are Sensitized After Drying By Floating On A Solution Of Silver Nitrate And Again Drying (de Brebisson, 1854). The Keeping Qualities Of ...

Self Toning Papers 545
Self-toning Papers 545. Types Of Self-toning Papers. The Addi Tion To The Emulsion Of The Gold Salts Necessary For Toning Prints On Print-out Paper Was Sug Gested Before 1860, But It Was Not Until 1896 That P. E. Schocnfelder And E. Kehle Worked Out A Commercial Process. For Some Years ...

Shutters 127
Shutters 127. Preliminary Remarks. Although In The Earliest Days Of Photography The Word Shutter Was Used To Signify The Cap Of A Lens, And Then At A Later Date The Different Arrangements (flaps, Etc.) Worked Directly By Hand, The Word Is Now Used To Describe Any Mechanism By Means Of ...