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)
A photo paper used for contact printing that is exposed with sunlight, making the image visible. After the image is printed out, that is the image has appeared and darkened to a desirable value, it is taken out from the light and fixed in a bath.

Dear Doctor Card
An advertising card published by Abbott Laboratories during the mid 1950’s to promote the Barbiturate Sodium Pentothal. The 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. When pulp is poured onto a paper making screen and left to dry, the area that overlap the frame’s bevel form a thin deckle. A sheet of paper with four deckle edges indicates it was made on a small screen, possibly by hand. If only two sides of a sheet of paper have deckle edges it means it was factory produced in a long role and then cut into sheets. For commercial printing the entire deckle is cut off to facilitate its passage through a press and proper registration. Papers with deckle edges are usually reserved for fine art printing that is done by hand. The edges of paper may be torn off in a manner that gives the illusion of a deckle. This method was used on some postcards to impart an association with a fine art print.

Defender
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 of poorer quality.

Delft Blue
A very distinguishable hue used on tin glazed ceramics from Holland, first used in the city of Delft in the 17th century. After 1602 when the Dutch East India Company began substantial trade with China, porcelain became a highly coveted commodity. But since the Europeans had little the Chinese wanted in trade they refused to give up the secret of porcelain production and it remained so expensive only the wealthy could afford to import it. Eventually the potters in the city of Delft developed a blue and white, low cost substitute for Porcelain. It became so popular it still creates associations with Holland today. Both printed and real photo postcards where manufactured in a delft blue. While some cards used it on Dutch themes, others just used the name to describe their monochrome color.

Deltiology
The study of postcards, taken from the Greek logos (science), and deltion (writing tablet). 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 postcard collecting so it is looked upon as more than a hobby. It is not an internationally accepted term and is not used by most collectors.

Density (Optical Density)
The ability of a material to absorb light. The less reflective, the higher the density and the more dark and opaque it appears.

Develop Out (DOP)
The processing of various types of photosensitive emulsions, where the image only begins to appear after interaction with a chemical developer. Developing out photo papers were not very popular when first introduced because the correct exposure time they needed was guess work that cost time and money with every mistake. It was only when photographs were being reproduced in large quantity in a controlled setting that its use made sense. But as negatives grew smaller with more compact cameras, enlarging became necessary and the slower printing out papers could no longer be used.

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

Dialect Cards
A postcard with a caption printed in a local or stereotyped dialect rather than with the proper spelling and grammer of the language.

Diapositive
A transparency. The term is sometimes specificaly used to refer to lantern slides.

Dichromate Colloid
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 forms the basis of most photographic processes. The Scott, Mungo Ponton discovered the effects of light on dichromate in 1839, while in France, Alphonse Poitevin noted the hardening effect of light on dichromated colloids in 1855.

Die Cutting
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 not as precise. Die cut postcards were most often made for advertising and are considered novelties.

Digital
The use of a binary code, zeros and ones, to record any type of information such as text, images, sound, or video. Information recorded digitally can easily be manipulated and transmitted.

Dithering
A process by which a computer program fills in missing color or pattern information on an image. Different digital recording systems may not record information in the same way, so a computer will add or subtract pixels of an image to simulate the missing parts according to a formula its program dictates. Dithering occurs most often when an image is resized. 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 postcard whose back is divided in two, segregating the left side for a message, from the right side for the address and postage. Great Britain was the first country to issue divided back postcards in 1902, followed by France and Germany. 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 inovation greatly increased the popularity of postcards.

Dot
The individual element of a halftone. Its size is in 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.

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

Double Toning
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.
To designate a discontinued Post Office cancel (postmark). Many small Post Offices in rural America were run out of other small businesses such as a general store where the owner would act as postmaster for a few minutes of the day. But as our population grew and shifted many of these small Offices were closed down or combined to create new Federal facilities with full time employees. In other places whole towns have since disappeared leaving only postmarks behind.

D.R.G.M.
An abbreviation for Deutsche Reichsgebrauchmuster meaning Design Registration. It is found on some German printed cards as a type of copyright notice.

Druckchrome
A trade name for a type of postcard distributed by the American News Company that was printed with a black halftone, and then overlaid with continuous toned bright lithographic colors. These cards were manufactured in Germany.

Dry Plate
A clear glass plate coated with a silver bromide gelatin emulsion that is used when dry 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 just before the picture was taken, then developed immediately afterwards. Because these new plates had a 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)
An image created by the photo engraving process invented by Louis Levy in 1914. Two plates of the same image would be made with halftone patterns placed at different angles. One plate would print a black or dark color, and 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 consistancy. Traditionally made from vegetable matter, most now are synthetically based providing more variety and perminence, 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.