Glossary

Acetate

Is made from a cotton or wood pulp that has undergone processing, defining it synthetic. It reacts to high concentrations of alkalis or acids. Therefore at John Jones we use archival Polyester film which is often referred to by the brand names ICI Melinex or Mylar.

Back to Index

Acid Free

This can be a very misleading phrase, sometimes used to describe materials that have acidic content but which have in reality been highly buffered to raise the pH value. We use 100% cotton mount boards that contain absolutely no Lignin.

Back to Index

Acid

Acid attacks cellulose fibres causing paper to discolour, become brittle and breakdown. Acid comes from the lignin in wood. It can also be contained in chemicals used in paper manufacture, lower grade picture framing materials and atmospheric pollution.

Back to Index

Acrylics

Plastic glazing material that is lighter than glass, ideal for larger artworks. We mainly use Perspex, Optium and Artshield. With these products you can select whether you need Ultra Violet light filtering (UV), low glare (LG) or low abrasion properties included. The drawback to this product is that due to holding a static charge it is not suitable for glazing pastels charcoals or fine lightweight papers.

Back to Index

Adobe RGB (1998)

The RGB working space created by Adobe Systems. Adobe RGB’s gamut is reasonably large; it encompasses most of the colours that can be reproduced by common output devices today, and is considered the standard colour space for converting and storing images.

Back to Index

Alkaline

Materials with a pH level more than 7.0 will contain alkali, neutralising (but not removing) acidic content.

Back to Index

Artwork Present. Template

This headlines how you want the artwork to appear in the finished frame. There are twenty three different options of presentation and they will all fall into one of the following option groups… To Edge, Mount or Lay-On.

Back to Index

Ancillary materials

Any materials within the microclimate in which an artwork is stored (e.g. newspapers included within a frame, or the wooden backboard of a frame without interleaving vapour barriers)

Back to Index

Archival

Archival quality is a non-technical and unenforced term that suggests that a material or product is permanent, durable or chemically stable

Back to Index

Artist’s Proof

Artist's Proofs are a special subset of the regular limited edition. In the modern day, they are usually created to view how the final image is going to print and are typically the same in quality as the numbered prints. Artist's Proofs usually sell for 10-30% more than the regular edition.

Back to Index

Art Sorb

Art Sorb (R) is a hygroscopic silica material, similar to silica gel, that is ideal for slowing fluctuations in relative humidity within a microclimate in which it is included (e.g. inside a frame).
John Jones stocks Art Sorb (R) in sheet form.  It can also be sourced as beads or blocks upon request.

Back to Index

Bleed

When an image is printed to the edge of a piece of paper, it is said to bleed to the edge.

Back to Index

Burnished

A high shine, smooth finish applied to gold leaf frames by hand polishing with an agate quartz stone.

Back to Index

Backboard

Exterior backing must be chemically inert or acid free and ideally should be puncture proof.

Back to Index

Backing

Internal backboard, usually visible (but not always), used to protect or help display the artwork.

Back to Index

Bevel

Angled edge cut into a mount aperture or into part of a frame profile.

Back to Index

Baguette Frame (Tray Frame)

Box solution to float a canvas or a work on board (usually oils). Always unglazed.

Back to Index

Buffering

The addition of an alkaline substance usually Calcium carbonate in order to help neutralise, prevent (or even disguise) acids.

Back to Index

Box Frame

Frame designed to house an artwork using fillets (spacers). Generally quite contemporary and glazed.

Back to Index

Bracketing

Practice of making additional images varying exposure to insure accurate exposure of a given subject; e.g., additionally exposing “one stop under” and “one stop over.” Automated feature in recent camera models.

Back to Index

Buffered Mount Board

Buffered mount boards contain an alkaline filler which raises the pH value of the product from 7.0 (neutral) to 9.5 (high alkaline) to reduce the possibility of acids forming within the adhesive layers.

Back to Index

Board

Board is composed of layers of compressed paper
e.g. 8-ply board is made up from 8 layers of paper

Back to Index

Blind-stamp

Letters or an emblem embossed into paper or board without ink being used  e.g. the K (within a square) of Kelpra Studio (print studio)

Back to Index

Blue-black ink

An iron-gall ink variant, containing both a dye and a metal ion/organic acid ink

Back to Index

Bromoil print

A type of pigment-based photograph. producing unique images.
Production involves bleaching away a silver-based image in order to selectively harden the gelatine.  It is wet-out using water to create a partially oil-rejecting surface, and oil-based ink is then applied using brushes.

Back to Index

Bleaching using light

Using visible wavelengths of light in alkaline conditions to lessen discolouration within paper by oxidising colour-causing carbonyl groups on the cellulose chain to acid groups co-ordinated to alkaline-earth-metal ions.  De-acidification is also required afterwards.

Back to Index

Blotting paper

European paper with very little or no sizing, making it very absorbent

Back to Index

Conservation level framing

The Fine Art Trade Gild is the UK trade association for the fine art framing industry and has defined five professional levels of framing which are recognised around the globe. Conservation level is the 2nd highest level designed to visually enhance artwork and offer a high level of protection for approximately 20 years under normal conditions. John Jones no longer offer framing at conservation level and concentrate solely on Museum standard.

Back to Index

CMYK

Acronym for Cyan (process Blue), Magenta (process Red), Yellow and Black, the primary colours of ink used in professional printing process to which Black is added for enhancement or for true Black. Not to be confused with the primary colours of light which are Red, Green and Blue (RGB).

Back to Index

C-type Print

A colour print in which the print material has at least three emulsion layers of light sensitive silver salts. Each layer is sensitized to a different primary colour - either red, blue or green - and so records different information about the colour make-up of the image. During printing, chemicals are added which form dyes of the appropriate colour in the emulsion layers. This is the most common type of colour photograph. It is now possible to produce C-type prints digitally while still maintaining the chemical processing.

Back to Index

Calcium Carbonate

The buffering agent most commonly used in the manufacture of paper. The higher pH achieved by buffering is not permanent and the alkaline reserve will eventually drop over time.

Back to Index

CCD

Charge Coupled Device: one of the two main types of image sensors used in digital cameras. When a picture is taken, the CCD is struck by light coming through the camera's lens. Each of the thousands or millions of tiny pixels that make up the CCD converts this light into electrons. The number of electrons, usually described as the pixel's accumulated charge, is measured, and then converted to a digital value. This last step occurs outside the CCD, in a camera component called an analog-to-digital converter.

Back to Index

CD-R

CD-Recordable. A compact disc that holds either 650 or 700 MB of digital information, including digital photos. Creating one is commonly referred to as burning a CD. A CD-R disc can only be written to once, and is an ideal storage medium for original digital photos.

Back to Index

Coated Glazing

Glazing and Acrylic can be coated with either a fine film or spray to increase UV filtration, abrasion resistance or reduce glare.

Back to Index

Colour Profile

A representation of the colour properties of a device's colour space. Today, virtually all profiles conform to the ICC specification.

Back to Index

Colour Space

A visual representation of a device or colour model's colour gamut used for colour management.

Back to Index

Conservation boards

Conservation boards are made from wood pulp that has all of the Lignin removed. They contain a small amount of a buffering to protect the board from acidic pollutants. The pH level achieved will fall in time and the board will turn acidic eventually so 100% Cotton Museum is the preferred option.

Back to Index

Conservation/Museum Glass

Glass that contains enhanced UV filtering to reduce the damage caused by Ultra Violet light. Traditional “float glass” will only filter 40% where as Conservation/Museum glass can filter as high as 98%.

Back to Index

Cotton Museum Mountboard

Superior to Conservation Mount board because it is made from pure 100% cotton fibre so does not contain acidic lignin like boards made from wood pulp. This board will be buffered in the main to prevent acidic content forming within its adhesive layers.

Back to Index

Corrosion intercept

Containing highly reactive copper particles bonded into a polymer sheet it neutralises corrosive gasses and is not affected by moisture, humidity and temperature. This material can be used as an additional barrier sheet between your artwork backing board and the frame backing. Once the copper colour changes to black you will need to replace it with a new one, this colour change will be identified upon regular “health” checks of your framed artwork.

Back to Index

Cromalin

Often misspelled as Chromalin. Cromalins are a well known photo-mechanical proofing method from DuPont'. They are capable of producing CMYK proofs as well as spot colour and Pantone Matching System proofs.

Back to Index

Carbon print

A type of pigment-based photograph.  The image is composed of pigment in localised gelatine. 
Production involves exposing the pigment-containing gelatine layer sensitised using dichromate salts.  The non-hardened areas are then washed away leaving an image with a distinctive relief surface.
Carbon prints have also been used as printing matrixes.
Pigment-based digital prints have sometimes mistakenly been called carbon prints.

Back to Index

Chromogenic print (Chromogenic dye coupler print) (C-Print)

A colour photograph based upon three colour dyes.
The standard colour photograph.  In production, three separate colour dyes are bonded to couplers of the silver contained in the paper’s emulsion. The silver is then removed to leave the remaining colours.

Back to Index

Chelating agent

A large soluble molecule with several available, co-operating reaction sites, making them particularly good at bonding with certain metal ions, and so making the metal ions more soluble.  Chelating agents can also sometimes have a detergent-like effect

Back to Index

Chine-collé

A technique in printmaking where, during printing, thin paper is placed between the printing matrix and a larger, heavier sheet of paper.  This creates an artwork where all the papers present are integral to the work.  The thin paper is usually selected for its colour or smooth surface texture (capable of accepting very fine detail), and adhesives are usually used between the papers.  The term ‘India-laid’ has also been used to describe some chine-collé prints.

Back to Index

Consolidation

Adding a substance to increase the binding of the media to the support.

Back to Index

Cibachrome / Ilfachrome

Making color prints directly from a transparency (a “slide”) is known as the Cibachrome process. Unlike chromogenic processes, the dyes are built in to the paper’s emulsion and selectively bleached out during development. These prints are valued for their saturated colors and increased archival stability (60-80 years) over traditional chromogenic processes.  They are very easily damaged and often presented without glazing – a recipe for disaster. Water is like acid to them and they are easily scratched or marred. Very few printers provide cibachromes anymore.

Back to Index

Cross-linking

One of the many reaction routes that many polymers undergo as they age.  Cross-linking between molecules can make the substance less soluble and can cause them to change shape, causing shrinkage

Back to Index

Digital Images

These are created using a gridded mosaic of light sensitive picture elements, called pixels, embedded on a computer chip. The pixels emit electrical signals in proportion to the amount of light they receive and these signals are converted to numbers and then stored electro magnetically - in a computer or on a disc, for example. Digital images can be manipulated and altered by computer and regenerated in many ways: on computer or television screens, on film, printed or projected. The technology for producing digital images is evolving rapidly with new possibilities constantly emerging.

Back to Index

Diasec ®

This process makes it possible to glue images double-sided between various types of materials. In this is way the Diasec ® process is also called a “sandwich”.

Diasec ® uses a specialized liquid glue which guarantees that no air bubbles, dust or residue will interfere with the quality or presentation of the art work.

No heating is used in the process and therefore the integrity of the image is not endangered.

Back to Index

DPI/PPI

Dots Per Inch/Pixels Per Inch. The resolution of an image or how many pixels are defined in the boundary of a square inch. The more correct term is pixels per inch, however dots per inch is often used instead.

Back to Index

Deckled edge

Paper with uneven, feathered edges which should be float-mounted so that the whole sheet is on view.

Back to Index

Distilled Water

Distilled water is highly-purified water produced by condensing the steam from boiling water.  Such highly-purified water should always be used in connection with Museum level framing, for example, on preparing reversible adhesives for applying Japanese paper hinges.

Back to Index

Dry Mounting

Bonding paper entirely to a substrate keeping it permanently flat, using a heat activated adhesive on acid free tissue with a flat bed press or rollers. This is very effective on Cibachrome photographs with a 1.5mm Aluminium sheet acting as the backing.

Back to Index

Duratran

Duratran is a trademark name used to describe a large format, backlit transparency, presented in a display lightbox. They are popular with photographers and artists working with digital images. The surface is delicate and should be handled with white cotton gloves.

Back to Index

De-acidification

Using an alkali to neutralise acids within an artwork and to impart a protective alkaline reserve which will continue to be neutralise acids in the future.  The alkalis used are molecules containing atoms of alkali earth metals (Group II of the Periodic Table).

Back to Index

Detergent

Long-chained molecules which, by the different properties of the different regions on the chains, can make it easier to suspend some substances in solution e.g. lifting dirt particles from an artwork into water used during washing

Back to Index

Digital C-Print /  Lamda /  LightJet /  Luminage Direct Digital Prints

A digital print structurally identical to a photographic C-print, incorporating three colour dyes.

They are made by computers and lasers printing with light on regular chromogenic photo papers, which are then chemically processed the in the same way as a standard enlarger-exposed c-print.
 

Back to Index

De-ionised Water

De-ionised water is highly-purified water, the production of which includes a filtration stage where any ions or charged particles are removed.  Such highly-purified water should always be used in connection with Museum level framing, for example, on preparing reversible adhesives for applying Japanese paper hinges. 

Back to Index

Dibond®

Dibond® sheets are made using a polyethylene core faced front and back with powder-coated aluminium.  Rigid, chemically stable, and an effective vapour barrier, it is often used as a backing within frames to provide support and protection for artworks.  It can be covered using paper or textiles, and lends itself to specialist slot-mounting techniques used to prevent distortions, rips and tears.

Back to Index

Fillet

Sometimes referred to as spacers, these strips traditionally made from wood or mount board are placed within a frame chamber to separate the artwork/mount from the glazing to prevent adhesion, a common problem with photographic papers. John Jones use a revolutionary acid free paper covered Perspex fillet (Patent’s pending) which unlike the wood version will not contaminate the frame chamber over time.

Back to Index

Float Glass

Traditional picture frame glass normally supplied in 2mm thickness upwards. However glass technology has come a long way in recent years and we supply a low iron glazing as our base product, which eliminates the slight green tint associated with traditional float giving a clearer view of the object.

Back to Index

Formaldehyde

Is a substance used in the manufacture of MDF, textiles, leather and paper. It occurs naturally in some plants and contains formic acid which is a corrosive.

Back to Index

Giclee

Pronounced zhee-klay the French word giclee is a noun that means a spray or a spurt of liquid. The term giclee print connotes an elevation in printmaking technology. Images are generated from high resolution digital scans and printed with archival quality inks onto various archival substrates including canvas, fine art rag paper, and photo-base paper. The giclee printing process provides better colour accuracy than other means of reproduction.

The quality of the giclee print rivals traditional silver-halide and gelatin printing processes and is commonly found in museums, art galleries, and photographic galleries.

Back to Index

Gesso

Made from a mixture of plaster, chalk and glue, gesso is the base onto which gold leaf (gilding) is applied. It can be carved and moulded enabling it to be used to make decorative frame mouldings.

Back to Index

Gamma

The values produced by a monitor from black to white are nonlinear. If you graph the values, they form a curve, not a straight line. Gamma defines the slope of that curve at halfway between black and white. Gamma adjustment compensates for the nonlinear tonal reproduction of output devices such as monitor tubes. Gray Gamma 1.8 matches the default grayscale display of Mac OS computers. Gray Gamma 2.2 matches the default grayscale display of Windows computers.

Back to Index

Gamut

The total range of colours produced by a device. A colour is said to be “out of gamut” when its position in one device's colour space cannot be directly translated into another device's colour space. For example, the total range of colours that can be reproduced with ink on coated paper is greater than that for uncoated newsprint, so the total gamut for uncoated newsprint is said to be smaller than the gamut for coated stock. A typical CMYK gamut is generally smaller than a typical RGB gamut.

Back to Index

Gilding

The highly skilled and delicate application of laying gold-leaf onto a surface.

Back to Index

Glass (WW)

Water white glass (WW) has a low iron content. As a result, the glass appears whiter, losing the slight green tint associated with traditional glazing. The main benefit is a greater clarity when viewing your artwork within the frame.

Back to Index

Glass (WW LG)

In addition to being a water white (WW) glass with a low iron content, this variety has a low glare (LG) coating that reduces light reflection from a standard 8% down to 1% making it difficult to detect.

Back to Index

Glass (UV LG)

This option has the addition of a ultraviolet light (UV) filter, as well as incorporating low glare (LG) properties. Standard float glass has a natural filter in the region of 44% which can be increased to 99% by using UV coated or laminated products. However, this version of glazing is not low iron like water white (WW) glass, and retains the usual tint of standard glass.

Back to Index

Glass (WW UV LG)

As a water white (WW) glass with low iron content, an Ultra Violet light filter (UV) and a low glare coating (LG) all combined, this glazing option has proven to be our most popular choice. This glass also comes in a laminated variety, which is more suitable for large-scale artwork.

Back to Index

Grey Scale

An image made up of varying tones of black and white, containing no colour, so greyscale is synonymous with black and white. The 256 grey levels system divides the grey scale into 256 sections with black at 0 and white at 255.

Back to Index

Gelatine

A substance derived from animal skin and bone.  Various grades of purity are available, and the animal source can be selected to fit in with cultural traditions.
Its uses include; as an adhesive, a sizing agent, and a pigment-bearing emulsion in photography.
Gelatine might be able to bind with transition metal ions, lessening their catalytic effects.

Back to Index

Humidity

In order to ensure its longevity artwork should be hung in a stable atmosphere where the temperature and humidity levels are not susceptible to rapid change. Temperature should ideally be within 65 & 75°F (18 & 24°C) with humidity ranging 45% - 55%

Back to Index

Hinges

Used to secure an artwork into a mount along one edge only, so that the artwork can be lifted and the back inspected

Back to Index

Hygroscopic

Used to describe a material that releases and absorbs moisture to and from its environment (as dictated by conditions)

Back to Index

Hysteresis

The lag in the response of an object to a change in its environment, making its current state dependent upon past as well as present conditions

Back to Index

Image Resolution

The number of pixels in a digital photo is commonly referred to as its image resolution.

Back to Index

ICC Profile

The International Colour Consortium, a group that sets standard guidelines for colour management in the imaging world. Most printers, monitors and scanners as well as digital cameras, usually come with a driver disc for Windows and Mac systems that includes ICC profiles for the particular device.

Back to Index

Image Size

This refers to the “actual picture” not paper size or any plate line/borders. Borders, plate lines and paper sizes are all recorded separately for accuracy and are used dependant on the artwork presentation template chosen.

Back to Index

Inter-negative

An inter-negative is made by duping a positive slide or transparency onto colour negative film. The inter negative can then be printed on colour negative (Type “C”) paper. Negative printing materials have lower contrast than do positive papers, but the inter-negative process will reduce overall sharpness and colour saturation.

Back to Index

Inkjet prints

These are printed using small drops of ink sprayed from a printer.
Archival inkjet prints and digital pigment prints specifically refer to prints with inks based upon pigment suspensions rather than soluble dyes
Another term for inkjet prints is Gicleé prints, which may be either pigment or dye based.

Back to Index

Inclusions

Debris and fibre knots incorporated in paper as the sheet was formed

Back to Index

Infrared light (IR)

The type of ‘light’ (electro-magnetic radiation) that is in the region immediately after the ‘visible light’ region in the spectrum (i.e. it has a longer wavelength).  Because of resonance effects it is an important factor in heat transfer, and it is essential to consider the IR emissions of exhibition lighting.
The ability of different pigments to reflect, transmit absorb different IR wavelengths can be used in the examination of artworks.

Back to Index

In-fill (noun)

A shaped piece of paper used to fill a loss in a support

Back to Index

Inlay

Securing an artwork within a wider paper support, often with an aperture behind the artwork, allowing the back to be inspected

Back to Index

Interventive treatment

Work carried out to improve the appearance or stability of an artwork through changing it in some way

Back to Index

Iron-gall ink

A traditional ink made from iron salts and tannins/gallic acids processed from oak galls (alongside other ingredients such as gum Arabic).  The inks often begin black and fade to brown as they age.  There are several variations on the metal ion/organic acid recipe.  The inks can be associated with localised paper deterioration as they are acidic and contain transition metal ions

Back to Index

Japanese Paper (hinges)

Japanese papers are lightweight, strong and long fibred which is important when attaching artworks to the substrate. Once torn and feathered for soft edges, the likelihood of the hinge creating a ridge that shows through to the front of the artwork is much reduced. Paper will always react to moisture addition however Japanese hinging is the ultimate attachment method for museum standard framing. It is important that the paper selected is of a lighter weight than the artwork paper, so if by any chance the frame was to fall from the wall, on impact the hinge would tear and not the artwork.

Back to Index

Joining

Term used to describe fixing the corners of a frame together - splicing, screw plug, underpinning, butt join are a few references.

Back to Index

JPEG

Acronym for Joint Photographic Experts Group that describes a digital image file format standard in which the size of the file is reduced by compression. A JPEG image file name carries the extension “jpg”. JPEG compression is “lossy”, meaning it loses some image information as opposed to other formats like TIFF. A “high quality” JPEG file looses less than a “low quality” JPEG file.

This is a common standard on the WWW, but the data loss generated in its compression make it undesirable for printing purposes.

Back to Index

Japanese paper

These are often used in conservation treatments as they have very long-fibres, giving them good strength relative to their thickness

Back to Index

Laminated Glass

By inserting a plastic laminating film between two sheets of glass and bonding them together, a thicker and much larger sheet of glass is instantly available widening the usage of glass containing WW UV LG properties. In the unlikely event of being broken, laminated glass will not detach from the film thereby keeping your artwork much more protected from damage than it would if single sheet glass is used. By using a laminated product you also instantly introduce a 99% Ultra Violet light filter.

Back to Index

Lay-on

Artwork presentation template. The object is placed onto a backing usually larger than the paper size so that it is made visible, then it is secured using Japanese Hinges.

Back to Index

Lining (noun)

A material adhered overall to the back of an artwork, usually to add support.  Japanese paper is commonly used as a lining for art on paper.  Natural fibre textile linings adhered to paper artworks can present a number of problems

Back to Index

Lignin

A naturally occurring polymer in wood-pulp paper (e.g.newsprint) that rapidly degrades, typically turning yellow and producing significant levels of acids and other VOCs. Lignin is removed from conservation level mount boards and other conservation framing materials.

Back to Index

Light-damage

Light can provide energy that increases reaction rates (and so speeding up damage) or a portion of the light may be at  the specific wavelength to have a resonance effect with bond lengths within the molecules affected.

Back to Index

Lining (verb)

The process of adding a lining

Back to Index

Lithograph

A printing process in which the image to be printed is rendered on a flat surface, as on sheet zinc or aluminum, and treated to retain ink while the non image areas are treated to repel ink.

Back to Index

MDF

Medium Density Fibreboard. Although used by many as a frame backing, for purity reasons we do not. MDF is made from various scrap wood fibres including sawdust and is bound together with an agent that contains formaldehyde, incorporating formic acid which is a corrosive.

Back to Index

Microchamber technology

Has the ability to delay the deterioration of objects longer than buffered 100% cotton alone. Containing molecule traps called Zeolites, mount boards and paper impregnated with this technology allow airborne pollutants into the very fibre of the material but will not release them, rendering them harmless in the process. We offer a selection of 100% cotton boards with Microchamber technology within our mountboard range.

Back to Index

Moulding

The name given to describe the shape of a wood profile used to create a frame.

Back to Index

Migrating acid

Acid contained within a poor grade mountboard or frame component for example will eventually move into the artwork. Similarly should an artwork already contain acid this will infect a poor grade mountboard.

Back to Index

Mount (Bleed)

Bleed refers to the amount of artwork paper you wish to see around the artwork image through the aperture when overlaying it with a mount.

Back to Index

Mount

A mountboard cut to the rebate size of a frame with a central aperture (window) created through which to view the artwork image only.

Back to Index

Mount (Book)

All mounts created by John Jones come with a backing attached, hinged together like a book. It is to this backing that artwork should be attached and never to the underside of the cut mount.

Back to Index

Mount (Float)

Float refers to displaying the whole artwork paper for view within the mount aperture.

Back to Index

Museum boards

The highest and only grade of Mountboard available at John Jones offering maximum artwork protection. Made from 100% cotton which does not contain Lignin the question of acid in the product does not arise. Some of these boards are Unbuffered making them ideal for use with papers & mediums that are not suited to a high alkaline environment.

Back to Index

Museum Level framing

The Fine Art Trade Guild is the UK trade association for the fine art framing industry and has defined five professional levels of framing which are recognised around the globe. Museum is the ultimate level designed to visually enhance artwork and offer the maximum level of protection for up to 35 years under normal conditions. John Jones not only meets these standards but exceeds them where possible; work to improve our standards by continual research into new framing methods and materials is permanently ongoing.

Back to Index

Monoprint /  Unique print

A unique print produced in such a way that part of the process cannot reproduced (e.g. it may contain an element of monotype)

Back to Index

Monotype

A print made by drawing or painting on a smooth surface and transferring the image, creating a unique image.  Monotypes are one kind of monoprint

Back to Index

Negative

The developed film that contains a reversed tone image of the original scene.

Back to Index

Non-Reflective Glass

Non-reflective glass should not be confused with the low glare (LG) glass that John Jones offers. Non-reflective glass is a sheet with one etched side that breaks up the reflection. Although this looks fine when placed directly onto the artwork with nothing in between, once lifted 2mm or more the clarity of the artwork begins to suffer. John Jones therefore do not offer this glazing as it breaks museum standard rules. We believe that artwork must always be separated from the glazing.

Back to Index

Non-aqueous

Not involving water. 

Back to Index

Oxidising bleach

A bleach that lessens discolouration in paper by oxidising colour-causing carbonyl groups on the cellulose chain to carboxylic acid groups.  De-acidification is required afterwards to neutralise these acids.

Back to Index

Patina (Patination)

With our aluminium and brass frames we can create many different colour/finish effects with patination. It is achieved by the application of corrosive chemicals on the surface of the frame which are left for varying timescales before being removed once the desired effect has been realised. To seal and protect the finished surface an Ercelene Lacquer is added as a final step. In accordance with our strict codes of practice all chemical residue is erased before fitting the frame and artwork together.

Back to Index

PH Scale

The pH scale measures whether materials are high alkaline, acidic or neutral. The neutral measurement is 7.0 any result below that figure will indicate acidity. Likewise readings above will indicate alkalinity.

Back to Index

Perspex and Plexiglas

These are brand names that are generally used mistakenly when asking for Acrylic.

Back to Index

Profile (1)

The name given to describe the shape of a wood moulding used to create a frame.

Back to Index

Polaroid

An instant film, giving an almost immediate positive print.

Back to Index

Profile

An ICC description of a particular imaging input or output device that allows the Colour Management Software to apply the proper colour transformations to the image file to match the specific limitations of the device.

Back to Index

PVA neutral pH adhesive

Based on Polyvinyl Alcohol, it is used for securing wood frame corners and some forms of artwork presentation. PVA is also used to laminate paper sheets to make mountboard as is EVA (ethylene-vinyl acetate)

Back to Index

Platinum prints and Palladium prints

A photograph in which the image is composed of finely divided platinum or palladium particles (or a mixture of the two) imbedded into the paper fibres.

Back to Index

Photomechanical reproduction

An image printed from a photographically produced matrix

Back to Index

Planar distortion

Distortions pulling a support out of plane, e.g. cockling

Back to Index

Plasticiser

A volatile compound incorporated into some plastics to adjust their physical properties (increasing flexibility). 
The loss of plasticers from an object can lead to embrittlement and changes in shape and appearance.
Plasticers migrating out of an object can adversely effect nearby materials.

Back to Index

Preservation / Preventive conservation

Work carried out to improve the appearance or stability of an artwork without directly changing the artwork

Back to Index

Pressure-sensitive adhesive

An adhesive that is formulated to stick on contact, at room temperature, and with no drying or curing time (e.g.the adhesive on masking tape, magic tape, or sellotape).

Back to Index

Primary support

The support upon which an artwork is executed (e.g. paper with watercolour paint on it)

Back to Index

Photo Corners

Shaped half-open enclosures of polypropylene or 100% cotton, unbuffered paper that are used to hold each corner of a photograph (or other artwork), holding it securely without directly applying any adhesive to the artwork

Back to Index

RAW

The RAW image format is the data from a digital camera as it comes directly off the CCD, with no in-camera processing performed.

Back to Index

Rabbit Skin Glue

An ingredient that is traditionally used in Gesso as a gilding base, Acrylic Gesso is available but it does not perform as well.

Back to Index

Raised Lay-on

The difference between this and a regular Lay-On is the addition (usually 100% cotton) of an extra platform on which to lay the artwork. Cut smaller than the paper size, it gives the illusion that the artwork is floating in front of the backing.

Back to Index

Rebate Size

The rebate of the frame is the inside of the frame where all of its components rest. Rebate size is the internal measurement which will tell you how big the glazing, backing, fillets etc need to be.

Back to Index

Recto

Front (Face) of an artwork.

Back to Index

Reversible

All methods of artwork hinging should be fully reversible. That is to say, if they are removed the object should be able to be returned to its original state prior to application.

Back to Index

RGB

Red, Green and Blue. The three colours to which the human visual system, digital cameras and many other devices are sensitive; the colours used in displays and input devices. They represent the additive colour model, where 0% of each component yields black and 100% of each component yields white.

Back to Index

Recto

Front of an artwork, or right-hand page in a book

Back to Index

Reducing bleach

A bleach that lessens discolouration in paper by reducing colour-causing carbonyl groups on the cellulose chain to hydroxyl groups, the groups that predominate in undamaged cellulose.

Back to Index

Split Batten

This is a corresponding length of wood used to marry a sub frame to the wall, providing a secure hanging system

Back to Index

Self Adhesive

Self adhesive tapes or hinges should never be applied directly to artwork under any circumstances whether it is for hinging or repair purposes.

Back to Index

Sight Size

This refers to the measurement telling how much of the object is visible once framed. When used this will differ to the image or paper size measurements. It is often more applicable for framed canvas’s or panels that are framed To Edge.

Back to Index

Sub frame (strainer or support frame)

Internal frame construction devised to add durability to a frame, as well as to provide a secure hanging method, by using a Split Batten.

Back to Index

Substrate

Is the backing onto which an artwork is applied or created.

Back to Index

Secondary support

A support to which an artwork is directly attached (e.g. thick board onto which a watercolour painting is adhered)

Back to Index

Shofu / Sho-fu / Shoufu

Purified Japanese wheat starch paste, containing only starch and no gluten

Back to Index

Silver-gelatine photograph

A photograph in which the image is composed of finely divided silver particles in a geltaine emulsion layer

These are chemically sensitive and the surface should not be touched unless wearing gloves.
 

Back to Index

Salted paper prints

A photograph in which the image is composed of finely divided silver particles imbedded into the paper fibres.

Such photographs are particularly chemically sensitive and the surface should not be touched unless wearing gloves.
 

Back to Index

Silver-albumin photograph

A photograph in which the image is composed of finely divided silver particles in an albumin emulsion layer.

Such photographs are particularly chemically sensitive and the surface should not be touched unless wearing gloves.
 

Back to Index

Silvering out

A deterioration process affecting silver/emulsion photographs.

It occurs when acids react with the finely divided silver particles that make up the image; the resulting soluble salts migrate out of the emulsion layer (a process encouraged by elevated levels of moisture), and on reaching the surface again react to form characteristic silvery surface deposits
 

Back to Index

Size

A substance added to adjust the working properties of paper by increasing its moisture resistance.  Traditionally European papers have been sized by dipping new sheets into gelatine.  Several modern papers now use synthetic sizes (e.g. alkyl-ketene dimer sizes) that are added to the stock before the sheet is formed.

Back to Index

Spot varnish

Localised areas of varnish, applied by printing, that form part of the design of an artwork

Back to Index

Surface cleaning

Using dry methods to remove dirt from a surface, e.g. by using a soft brush, or shards of eraser

Back to Index

Temperature

In order to ensure its longevity artwork should be hung in a stable atmosphere where the temperature and humidity levels are not susceptible to rapid change. Temperature should ideally be within 65 & 75°F (18 & 24°C) with humidity ranging 45% - 55%

Back to Index

To Edge

Artwork Presentation Template. This implies framing straight to the edge of the paper/canvas, some of which can then be obscured under the frame rebate. What’s left to view is called the sight size.

Back to Index

TIFF

Tagged Image File Format. An uncompressed non loosy image format.

TIFF can handle colour depths ranging from one-bit (black and white) to 24-bit photographic images with equal ease. Once the resolution has been determined, either by scanning or by saving in an image-manipulation software package, it cannot be upgraded or increased to improve quality.

Back to Index

Transparency

Basically, slide film. A positive photographic image on film, viewed or projected by transmitted light (light shining through film).

Back to Index

Tertiary support

A support attached behind a secondary support onto which an artwork is attached (i.e. it is the third layer present)

Back to Index

Tabs

‘Hinges’ used to secure an artwork along more than one edge, restricting its movement

Back to Index

Transition metal ions

Several metal ions with variable oxidation states catalyse the (sometimes quite rapid) deterioration of cellulose, and so are damaging to paper.  Of most frequent concern are iron ions and copper ions.  Although not strictly ‘transition metal’ ions, aluminium ions can also in some circumstances cause rapid paper deterioration

Back to Index

Unbuffered Boards

A category of Museum board that has no alkaline buffering added. Certain photographic processes react with alkaline-based materials, so it is important that un-buffered board is used for mounting certain types of papers or medium.

Back to Index

Ultraviolet light (UV)

The type of ‘light’ (electro-magnetic radiation) that is in the region immediately before the ‘visible light’ region in the spectrum (i.e. it has a shorter wavelength).  It is more energetic than visible light and so has a greater ability to speed up reaction rates (see light damage).  As some substances appear different in UV (e.g. by fluorescing a characteristic colour), UV examination is an important technique in investigating artworks. Ultraviolet light can be highly damaging to sensitive artwork. Even if your frame includes special UV-filtering glass, it should never be hung in direct or bright indirect sunlight. Ultraviolet rays are found in artificial light sources as well as in sunlight.

Back to Index

Verso

The back (reverse) of an artwork or left-hand page in a book

Back to Index

VOCs / Volatile Organic Compounds

Airbourne compounds that may cause deterioration in artworks e.g. acids from wood, solvents

Back to Index

Window/Aperture size

The dimensions of the central aperture (window) created in a mount through which to view the artwork.

Back to Index

Washline

A decorative line drawn around a mount aperture, using a special ruling pen with watercolour paint or ink.

Back to Index

Water White Glass

Water white glass has a low iron, high lead content that makes it virtually colourless in comparison to traditional Float Glass which has a green tint.

Back to Index

Window Mount

A mountboard cut to the rebate size of a frame with a central aperture (window) created through which to view the artwork image only.

Back to Index

Wetting agent

A substance used to lessen the surface tension of water, usually used to increase the rate at which an artwork absorbs water during washing

Back to Index

Wet-stamp

Letters or an emblem printed using a hand-stamp and dye-based ink

Back to Index

Zeolites

Microporous minerals capable of adsorbing, and effectively trapping, volatile organic compounds

Back to Index