LINGUA FRANCA – Chapter 2: Condition issues

Chapter 2: Condition Issues. Image of a landscape image of a burnt building. A man in a top hat in the centre and a woman sitting on the ground off to the left. This photograph has a finger mark in the top left corner.

Condition issues

Weeping glass

This condition is caused by an inherent fault in the chemical composition of the original glass formula. Exposure to high levels of relative humidity during storage or display causes salts to hydrate and leach out of the glass. Alkaline droplets then form on the surface and appear as if the glass is crying or weeping.

A woman sitting with her arm resting on a table. Glass is deteriorated and appears to be weeping. Close-up of someone removing the cover glass of a daguerreotype.


Photographs on metal supports are subject to corrosion and degradation caused by oxidation of the metal. The surface of a daguerreotype is susceptible to tarnish. Tarnish on daguerreotypes is composed of silver sulphide, silver oxide and silver chloride. Tarnish may appear at the edge of the brass window mat opening or over the entire plate. It can be characterized by a series of interference colours and/or pale grey, blue, green, brown or black.

A brass locket of a man with blue and brown tarnish around the edges.


Minute organisms known as mould spiders grow and feed on organic matter in high relative humidity, high temperature and stagnant air. Mould can be identified by white or beige tendrils with a well-defined elevated centre growing on the surface of photographic material.

Three young girls; two are seated on either side, while one stands between. Mould is exhibited around the edges. A close-up of mould along the edge.


A missing fragment of the support or emulsion layer on a photograph.

A view of the rooftops of Parliament. Loss of photographic support along the edges. A close-up of emulsion loss.


A split in a photograph support or emulsion caused by it having been pulled apart forcefully.

A paper negative of a rail track in a barren landscape exhibiting a diagonal tear. A close-up of a diagonal tear.


A line, groove or ridge made by folding or crushing where the surface of a photograph remains unbroken. It can be caused unintentionally when a substrate bends over itself.

A woman seated by a window with face turned away. Above are antlers. A close-up: exhibiting a crease along the bottom edge.

Credit: Yousuf Karsh


A bend in a material that may result in a crack or break in the emulsion / support, as one part of the emulsion or support is laid over itself.

A young man seated with waterfalls in the background. Image is horizontally bent along centre. A close-up of hands rotating a tintype. Horizontal bends can be seen


The physical process of scraping, roughening or wearing away an object's surface due to repeated friction or contact with other surfaces.

Image of a woman standing at a fence with waterfalls behind. Image appears to be scraped or abraded along the top. A close-up of vertical abrasion.


Physical damage which causes an indentation. The term usually implies that there has been some loss to the support or emulsion layer of a photograph.

A double image of a man walking on a tightrope, holding onto a horizontal pole and with a ring around his ankles. The image exhibits a small scratch, on the right image at the bottom edge. A close-up of a small scratch.

Silver mirroring

Silver Mirroring is a bluish-metallic deposit or sheen cause by a physical alteration of the colloidal surface of a photographic emulsion. It can change in reflective light and appear iridescent, even bronze in colour if severe. Over time, air pollutants in the presence of heat and moisture can create a sustained migration of silver ions in all directions.

Profile of a woman holding a dragon sculpture against her face. The photograph exhibits blue silver mirroring along the edges.


A mark left on the surface of a photograph caused by the oil, dirt or salt from perspiration found on a fingertip.

A landscape image of a burnt building. A man in a top hat in the centre and a woman sitting on the ground off to the left. This photograph has a finger mark in the top left corner. A close-up of a finger print.


Wrinkling or puckering in a wave-like manner that occurs when a photograph or a support dries unevenly or due to an extreme change in relative humidity.

A close-up image of a man with a turtleneck. A close-up: cockling is exhibited along the top edge.

Credit: Yousuf Karsh

Yellow discolouration

A change in colour of a photographic emulsion or a support, usually to a darker, more yellow or brown appearance. May be caused by light damage or exposure to acidic substances.

A snowy winter view of small hill with three people snowshoeing. This photograph exhibits yellow discolouration along the edges. A close-up of yellow discolouration along the edges.


Physical damage caused by a sharp object, resulting in a loss of the photographic emulsion and/or support.

Profile of a young girl sitting on a stool with a fluffy skirt. This photograph exhibits a small puncture along the top right edge. A close-up of a small puncture.


A discolouration that is caused by chemical or physical interaction between different materials.

An image of a very large tree with a hole, with a woman looking into the hole. A horse and cart are in the background. This photograph exhibits scattered staining along the edge. A close-up of yellow staining along the edge.

Flaking of emulsion

A small piece or fragment of emulsion that peels or falls away from the photographic support resulting in physical damage.

Close-up of flaking emulsion
Date modified: