A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Daylight Paper (Printing Out Paper)
Daylight paper is a generic name for any type of photo paper that is printed out, that is the image appears and darkens to a desirable value after being exposed to sunlight. After the image is properly exposed it is then taken out from the light and fixed in a bath. Daylight papers were only used for contact printing.

Dear Doctor Card
A Dear Doctor card is a continental sized advertising card published by Abbott Laboratories during the mid 1950’s to promote the Barbiturate Sodium Pentothal. Each card’s salutation began Dear Doctor, and hundreds of thousands were sent out to health professionals and institutions. They were mailed from various locations throughout the world with images of exotic places; and their messages can be found in Arabic, Dutch, French, German, Greek, Italian, Portuguese, Spanish, and Swedish in addition to English.

Deckle Edge
The uneven edge of a hand made paper is called a deckle. When pulp is poured onto a paper making screen and left to dry, the area that overlaps the frame’s inside bevel form a thin deckle. A sheet of paper with four deckle edges indicates it was made on a small mold, possibly by hand. If only two sides of a sheet of paper have deckle edges it means it was factory made in a long role and then cut into smaller sheets. In commercial printing the entire deckle is cut off to facilitate its passage through a press and insure proper registration. Papers with deckle edges are usually reserved for fine art printing that is done by hand. When the edges of paper are die cut or torn off in a manner that gives the illusion of a deckle, it is called a false deckle. This method was used on some postcards to impart an association with a fine art print.

Defender
Defender is a brand name of a photo paper and the Company that produced it. In 1896 Frank Wilmot founded the Defender Photo Supply Company in Rochester, New York. They had manufactured paper under the names Argo and Defender for real photo postcards from 1905 up until 1945 when the DuPont Company purchased them. Defender paper continued to be made until 1973 but it was of poorer quality.

Delft Blue
Delft blue is a very distinguishable hue placed on tin glazed ceramics from Holland, first used in the city of Delft in the 17th century. Its origins come out of the porcelain trade with China that was begun by the Dutch East India Company after 1602. Though a highly coveted commodity the Europeans had little the Chinese wanted in trade so they refused to give up the secret of porcelain production and it remained a luxury import. Eventually the potters in the city of Delft developed a blue and white, low cost substitute for Porcelain. It became so popular that it still creates associations with Holland today. Both printed and real photo postcards were manufactured in delft blue. While some publishers only used it with Dutch themes, others just incorporated the name to describe their monochrome color.

Deltiology
Deltiology, taken from the Greek logos (science), and deltion (writing tablet) is the study of postcards. The term was coined by Randall Rhoades of Ashland, Ohio in the 1940’s during a period of renewed interest and research into postcards. The term is meant to impart dignity to the act of postcard collecting so it is looked upon as something more than a hobby. It is not an internationally accepted term and is not used by most postcard collectors (deltiologists).

Density (Optical Density)
The optical density of a material refers to its ability to absorb light. The less reflective, the higher the density and the more dark and opaque it appears. Early postcards such as those printed in chromolithography had high density because light had to pass through many layers of ink.

Develop Out (DOP)
Developing out refers to the processing of any type of photosensitive emulsion, where the image only begins to appear after interaction with a chemical developer. Developing out photo papers were not popular when first introduced because their correct exposure time came down to guess work that would cost time and money with every mistake. This process was mainly used when photographs were being reproduced in large quantities within the controlled settings of a processing machine. As negatives grew smaller with more compact cameras enlarging became a necessity forcing the switch to developing out paper as the slower printing out papers could no longer be used.

Dextone
Dextone is a trade name for the early photochrome postcards printed by Dexter Press in the 1950’s. The poor optical blending in these cards tended to create a flat unnatural appearance. While individual colors might appear bright the overall effect was a dull look.

Dialect Cards
A dialect card is a postcard with a caption printed in a local or stereotyped dialect rather than with the proper spelling and grammar of the language. Under the guise of offering local color they were often used to disparage the group represented on the card by associating their unconventional speech patterns to ignorance.

Diapositive
A diapositive is a transparency. The term is sometimes specifically used in reference to lantern slides.

Dichromate Colloid
A dichromate colloid is a gelatin or albumen that has been made photosensitive by the addition of a dichromate, most commonly potassium dichromate. These emulsions harden when exposed to light and become insoluble in water. This reaction is the foundation of most photographic processes. The Scott, Mungo Ponton discovered the effects of light on dichromate in 1839, while working in France, Alphonse Poitevin also noted the hardening effect of light on dichromated colloids in 1855.

Die Cutting
Die cutting is a method of using metal blades formed into a shape (Die) to cut designs into products that straight cutting tools cannot accomplish. Most dies have a male and female part. The male part cuts the design while the female part provides support for the substrate. This process is performed on a flatbed press after the product is printed. Die cutting was eventually adapted to rotary presses but they are less precise. Die cut postcards were most often made for advertising purposes and are considered novelties.

Digital
The term digital refers to the reduction of any type of information such as text, images, sound, or video in to a binary code of zeros and ones. Information recorded digitally can easily be manipulated and transmitted as there are no unique components.

Dithering
Dithering is a process by which a computer program fills in missing visual information on an image. Different digital recording systems may not record information in the same manner, so a computer will add or subtract pixels of an image to simulate the missing parts of a color or decorative pattern according to a formula that its program dictates. Dithering occurs most often when an image is resized for there can be no optical conversion just the manipulation of data. Since digital images are stored in lines, the recording of non-linear patterns can result in a moiré pattern when dithering is employed.

Divided Back
A divided back postcard is one whose back is divided in two segregating the left side for a message from the right side reserved for the address and postage. Great Britain was the first country to issue divided back postcards in 1902, followed by France and Germany. To keep its cards uniform with that of other nations the United States released new postal regulations on March 1, 1907 that divided the back of its postcards in half. This date is often referred to as the birth of the modern postcard for it created the same card format that we use today. Prior to this date only the address and postage was allowed on the back of postcards. The divide was first accomplished by printing a line down a card’s back. On some of the earliest cards of this period the dividing line is left of center, often accompanied by printed instructions of what could be written and where. Another later variation eliminates the line but the words Correspondence and Address are printed in the appropriate places. Many undivided back cards continued to be used after 1907 and one may need to look closely to see if the dividing line has been drawn in when dating cards. As time went on the concept of the divided back was so accepted that they could be properly used with nothing at all printed on their backs. By permitting messages to be written on the back of postcards, the entire front could then be dedicated to holding an image. This innovation greatly increased the popularity of postcards.

Dot
A dot is the individual element of a halftone image. Its size is determined by its relation to the density of the original image used to create the halftone. The dot may consist of several shapes, round, square, or elliptical, all dependent on the type of screen used. A dot can also be the individual component of a Ben Day pattern.

Doubletone Sepia
Doubletone Sepia is a trade name for a type of sepia colored postcard distributed by the American News Company that were printed in gravure. These cards were manufactured in Germany.

Double Toning
Double toning is the practice of toning a photo paper with both a gold and platinum solution. This yields a neutral black rather than the brownish hue rendered by each toner individually.

D.P.O.
The initials D.P.O. are used to informally designate a discontinued Post Office cancel (postmark). Many small Post Offices in rural America were run out of small businesses such as a general store where the owner would take on the responsibilities of a postmaster for a only few minutes of the day. As our population grew and shifted to more urban areas many of these small Post Offices were closed down or combined to create new Federal facilities with full time employees. In other places whole communities have since disappeared leaving only postmarks behind. There are many who collect postcards just for their D.P.O. cancel.

D.R.G.M.
D.R.G.M. is a German abbreviation for Deutsche Reichsgebrauchmuster meaning Design Registered. It can be found on some German printed cards usually in connection with a number. It offers similar protections as a copyright notice for non utilitarian designs but only effective for a shorter period of time, 25 years in Germany.

Dry Plate
A dry plate is a clear glass plate coated with a silver bromide gelatin emulsion that is used after it has dried to create a photographic negative. Dry plates, invented by the English photographer Richard Leach Maddox in 1871, replaced the wet collodion process, where the emulsion had to be applied to the glass plate just before the picture was taken, then developed immediately afterwards. Because these new plates had a long shelf life they could be manufactured in quantity and sold as needed, and also developed at a convenient time. Dry plates were replaced when a way to coat flexible film with the same emulsion was invented and put into mass production by George Eastman in 1889.

Duograph (Duotone)
A duograph is a printed image created by using two photo engraved plates. This process, invented by Louis Levy in 1914 requires each of the two plates to be made from halftones of the same image only with each halftone screen placed at a different angle. One plate would be used to print a black or a dark color, while the second plate would print a lighter tint, often of the same color over it.

Dyes
Dyes are soluble colorants that have a tendency to soak into their substrates because they are used in a watery consistency. Traditionally made from vegetable matter, most dyes are now synthetically based providing more variety and greater permanence, but they are still particularly susceptible to the ultraviolet photons of the electromagnetic spectrum. In some cases this light will interact with the dye’s simple molecules causing them to decompose and fade. Other dyes are capable of turning certain wavelengths of the invisible spectrum into the visible, and transmit them back out. This is the basis of florescent colors and why the dye based inks of linen postcards look so bright.