Introduction
Utilizing extensive industry knowledge and 30 plus years of expertise,we have found a helpful guide to assist with various aspects of hot dry mounting and surface presentation for photographs, posters and other forms of artwork. This text should be combined with practical application of the techniques described, so that a reasonable level of competence is achieved before any important work is attempted. I/e Practice.. Practice..
Two general principles should be remembered at all times:
Cleanliness is next to Godliness. CLEANLINESS is vital to achieve top quality results. At each stage, always check for dust,board particles etc., trapped in the artwork assembly.Before putting the assembly into the press, always make sure that any exposed adhesive (whether facing upwards or downwards) is covered by a release paper or film.
Important points regarding specific pieces of equipment and associated items:
Mechanical presses (hard and soft beds) have a narrow throat or opening, which can make it difficult to insert work and ensure all items keep their relative positions. The use of a flat, rigid carrier board (e.g. 5mm MDF) on which to prepare work and slide it in and out of the press will assist greatly; mounting siliconised paper onto it (silicone side up) makes it non-stick and increases its life. All equipment is different…This is just a guide.
It is often beneficial to pre-dry mounting board and sometimes prints by putting them into the warmed-up press, separately, for a couple of minutes before processing. This is especially important where the relative humidity (dampness) of storage conditions can vary considerably even over short periods of time. Please note: prints should be dried between two pieces of matte absorbent paper (i.e. Kraft paper).
Silicone release paper and silicone release film are available as release agents; the film is double-sided. The silicone paper is cheaper, but the film lasts longer. However, silicone has a greater tendency to migrate onto the surface of glossy prints from silicone film than from silicone paper. When used in conjunction with a glass topped vacuum press, CLEAR silicone film allows the user to view work during dry mounting.
A print with any degree of gloss surface will show “orange-peeling” or dimpling when mounted onto card, even a good quality lined product such as white display board; this simply reflects the unevenness of the card’s core and cannot be totally avoided. Foam centered board is growing in popularity due to its flatness and smoothness, and acid free forms are available for the fine art market.
Dry Mounting with a HEAT PRESS or Vacuum Press
PERMANENT MOUNTING USING DRY MOUNT TISSUE
Set the press between 80°C and 90°C. Place the Dry Mount Tissue (DMT) between the print and the mounting board. It is usually important to maintain accurate placement of all these items prior to processing; although use of a glass top vacuum press with its combination of easy access and visibility can make it unnecessary. The initial assembly (known as “tacking”) can be done in various ways: All machines are different.
Tacking Using an Iron
Using the special heated tacking iron, tack the tissue lightly to the print at one end, and then tack the tissue to the board at the other end. This will hold the assembly in place but still allow creases or ripples to flatten naturally during processing. Tacking each component in more than one place can cause a crease to develop during the mounting process. The method of tacking described above is commonly known as “Z” tacking because when the board and print are moved apart the components (board, tissue, print) look like a “Z”.
Special Note - always place a small piece of silicone paper between the tissue and iron head to keep the iron clean.
Tacking Using Spray Adhesives
This method uses a spray adhesive. Spray a very small amount onto the middle of the mounting board, and place the dry-mount tissue in position. Then spray a similar amount onto the back of the art work, and place print in position. This holds the assembly in place whilst it is being put into the press. The spray adhesive disappears during the bonding process with no apparent detrimental effects, although too much spray mount may show through on thin prints.
Tacking Using Tape
Where a subject is to be centrally mounted onto a larger board and decorated with a window mount, the tissue can be cut to an intermediate size (larger than the print and smaller than the board). The assembly can then be held in place with a strip of masking tape during mounting. The indentation this will leave can then be hidden by the window mount.
Note - after tacking the tissue to the print (using any of the tacking methods), the tissue can be trimmed to size if desired, e.g. when center mounting or making a montage or collage of images.
Print and Heat Press Protection
Before placing the assembly into the press, please consider the following: It is usually desirable to protect your print from direct contact with the heated platen and also protect the heat press from any exposed adhesive which will stick to it.
Silicone Film or Silicone Release Paper will perform both functions; however the silicone can tend to offset onto some surfaces, particularly high gloss finishes, giving a blotchy appearance. When using glossy prints or photographs, tack the print and tissue together, trim off any excess dry-mount tissue, then cover the print with gloss acetate foil.
Processing the Work
Place the prepared and protected work in the press and process it under heat and pressure for 1 to 3 minutes. The precise time required will depend on various factors such as:
· Format - smaller items need less time
· Temperature - higher temperatures activate the adhesive quicker
· Heat Press Efficiency - how accurate the temperature indicator is
- how well temperature is maintained
- how evenly heat is distributed
- the amount of pressure applied
Please Note - When mounting a large imporous print such as a photograph in a vacuum press there is a possibility the tissue can be partly activated before all the air has been extracted, resulting in bubbles of trapped air. Cover the assembly with foam plastic. This provides a temporary heat insulation that allows time for all the air to be extracted.
When using a vacuum press, the phenomenon of “false vacuum” needs to be avoided. This can occur when two smooth surfaces are pressed together sufficiently tightly all around the edge of the assembly preventing air being extracted. The machines gauge will register that a full vacuum has been pulled, but the trapped air can result in a bubbled print.
Examples of this might be if siliconised paper or film is placed both above and below the assembly or when center mounting onto a large very smooth board (e.g. foam centered board), where the silicone seals itself onto the edge of the board and prevents air extraction. Foam plastic can be used on top of the assembly to help avoid this.
After Mounting/Laminating the photograph or image
Remove the assembly from the press, holding it flat. Place the work immediately on a cool flat surface under a weight to ensure adhesion and to help minimize bowing if using a foam mount board. This can occur over a period of time, but can be avoided by counter mounting onto the opposite side of the “bowed” board.
PERMANENT MOUNTING USING DRY MOUNT FILM
Set the press at 80°C to 90°C, as for Dry Mount Tissue. However, the work will require longer, usually 3 to 4 minutes to process fully. (it is usually desirable to pierce the film before use, although it is not absolutely necessary if mounting a porous print onto a porous substrate. The surface tack of the film avoids the need to tack the assembly into place prior to processing. However, avoid preparing work too near a heat source as this can cause problems removing and re-positioning the work).
Cut a sheet of film from the roll, either exactly to size or slightly larger, and pierce if appropriate. You will see that this film is protected both sides by release liners. Peel back about 25mm (1 inch) of one of the release liners and fold into a hard crease. (it is usual that when unrolled, the liner that was on the outside of the roll may tunnel away from the carrier. This is the side that should be peeled back first. Even if both liners tunnel, removing the outer liner first minimizes the chance of the carrier creasing and causing problems when mounting). Tape the roll up after use to avoid any undue tunneling.
Position the print accurately on the exposed film and press down from the middle to the edges. Then peel back the rest of the release paper, gently pressing the print onto the film as it is exposed - a cloth, squeegee or roller will help. When completed the dry mount filmcan be trimmed exactly to size.
Next peel back about 25mm (1 inch) of the second release liner and position the print onto the board. When in place, smooth down the exposed film (again from the middle to the edges) and gradually peel back the rest of the release paper as before.
Processing the Work
The assembly can then be put into the press with silicone paper or film over the top to protect the print from direct heat contact and to avoid any excess adhesive sticking to the press.
A heatseal film can also be applied at the same time if desired. If the work is to be heat-sealed using pre-pierced film (i.e. if the print is imporous) or if a stippled finish imparted by foam is required, then a sheet of foam plastic should be placed over the assembly in the press. If a porous print is being heat-sealed, foam may not be necessary. The film can then be covered with gloss acetate overlay foil for example.
After Processing
As with most mounting procedures, place the processed work on a cool flat work surface and position a weight on top to help minimize any bowing of the finished work.
REVERSIBLE MOUNTING
USING ARCHIVAL DRY MOUNT TISSUE
As the title suggests, this method of mounting can be reversed (see section below). Follow the instructions for permanent mounting using Dry Mount Tissue with regard to tacking, trimming and general processing. However, please note the following:
· Press temperature can be lowered (75°C - 80°C)
· Archival Dry-mount Tissue bonds as it cools (rather than as it heats up) and so great care needs to be taken when removing work from the press. The assembly should immediately be placed under a weight to allow it to cool down flat. DO NOT remove any protective covering until it has cooled completely.
REVERSIBLE MOUNTING
USING ACID FREE MOUNT FILM
Follow previous instructions for mounting but please note:
· This product cannot be tacked using a tacking iron; follow other suggested methods
· It does not always lie flat, so can be difficult to trim exactly to size. Therefore, it is often best left slightly over-sized if possible.
· Press temperatures are similar to Archival Tissue
· When removed from the press allow the assembly to cool completely as the film may still be easily removable. If it is not kept flat, problems may occur with the edges or corners of the work lifting.
REVERSING ARCHIVAL TISSUE & ACID FREE FILM
This is best achieved using a hairdryer, hot air blower or a domestic iron. A lot will depend on how vulnerable the subject is to a direct heat source.
Carefully reheat one corner of the print and gently lift it from the substrate (board). As the surfaces come apart, the tissue or film will remain stuck to either the print or the board (which one, depends on the relative porosity of each). Continue applying the heat to the area of de-lamination (the breaking point between the adhesive and the print or board), steadily and carefully pulling back the print. To help remove the print successfully, begin to roll it over a cardboard tube as it is eased from the board. Place some silicone paper or film over the adhesive as it is exposed to prevent re-bonding.
This process will need to be repeated if the adhesive has remained attached to the print.
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